Managing water for waders

blog L sittingYour task, should you choose to accept it, is to turn farmland into a haven for breeding waders. The only tools you have at your disposal are tractors and cows and we will give you permission to pump water out of nearby rivers when conditions allow. That’s how it started. These days the diggers look big enough to use on a motorway construction site!

If your aim is to maximise the number of pairs of breeding waders on your lowland wet grassland farm or nature reserve, then one of the key issues is to get the water levels right. This blog focuses on providing an appropriate mix of ditches, pools and grassland for species such as Lapwing, Redshank and Snipe and then keeping everything wet enough (but not too wet) during the important chick-rearing season.

This blog is not just about maximising the number of breeding waders on a nature reserve. It’s also about working with neighbouring farmers, in order to secure fresh water supplies for the future and to reduce the risk of salt-water inundations, associated with sea level rise. In the long-term, stakeholder engagement has proved far more important than habitat management, as you will read below.

Understanding water levels

When developing lowland wet grasslands for waders, an extra five cm of late-winter rain can make a huge difference, especially if you can capture as much as possible of the rain that falls or can draw water from a swollen river. Mark Smart, the Senior Site Manager for the RSPB’s Berney Marshes and Breydon Water reserve in East Anglia, understands grazing marshes and how to capture and distribute water, in order to provide the muddy edges where wader chicks find insects. An aerial photograph of Berney Marsh shows how Mark has designed a special landscape to capture winter rain – one that is ideal for Lapwings and other waders.

Mark has taken the lessons he has learnt on RSPB nature reserves and shared them widely, a contribution to conservation that earned him one of the 2018 Marsh Awards for Wetland Conservation from the Wildfowl & Wetland Trust.

From wheat and barley to ducks and waders

blog cow eatingThe marshes of the Norfolk Broads have been drying out for 2000 years. By the 1970s, and after over 400 years of farming, the Halvergate Marsh complex was on the point of being fully drained and by 1985 much of the wet grassland in which waders formerly bred had already been lost and turned into arable fields. At this point, the RSPB made its first purchase of land, as they tried to retain at least some of the threatened habitat which is so important to winter wildfowl and summer waders. At the same time, campaigning by local and national conservationists secured legal protection for the unique Broadland scenery and the species that rely upon the habitats it contains, thereby halting the advance of the combine harvesters.

The importance of Halvergate Marshes for wildlife has long been known, and in 1987 it became the site of the UKs first Environmentally Sensitive Area – the prototype for subsequent agri-environment schemes. Lowland wet grasslands are traditionally drained using ‘footdrains’ – narrow, shallow channels that connect low-lying parts of the fields with surrounding ditches, in order to drain them.

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The muddy edges of a footdrain

These same footdrains can be used to hold and manage surface water levels within fields, by blocking the ditch connections with sluices. In the 1990s, Mark pioneered the design and deployment of footdrains on lowland wet grasslands, and the kit needed for their construction. Through his skills, enthusiasm and collaborations with grassland managers throughout lowland England, footdrains and the water that they can contain are now a common sight. Many generations of wader families have enjoyed the invertebrate food that footdrains support.

The breeding season for waders is very short – with the first Lapwing claiming territories in March and most chicks fledged by the end of July. Outside these months, these wet grasslands provide excellent grazing for geese and ducks in the winter and cattle in the summer. The task of nature reserve managers is to work with graziers to try to ensure that cattle deliver appropriate sward heights for winter wildfowl and summer waders.

Not just water

fence 2By creating a hot-spot for nesting birds, within an intensively-farmed landscape, land-managers also produce a food-rich area for predators, attracted in by concentrations of eggs, chicks and sitting adults. Restricting the activities of species such as foxes and crows is an important part of the role of an RSPB warden, carried out through site management and active control measures. By focusing these activities in the winter period, the RSPB’s Halvergate Marshes team are able to stop corvids and foxes from setting up territories within the area that is managed for breeding waders. Electric fencing can help to prevent foxes moving onto the site in spring, while changing the way that core wader areas are managed helps to reduce fox/nest interactions by, for instance:

  • Adding shallow ditches in the right places can break up the site into compartments and reduce the likelihood that nests will be predated.
  • Leaving areas with long grass, that is good for small mammals and the mustelids and foxes that prey upon them, can change the focus of hunting activities.
  • Erecting temporary fencing, during at least the early part of the nesting season, can both provide protection and potentially increase the synchronicity of nesting attempts and hence the ability of birds effectively to mob predators.

blog L chickThere is more about these measures in these blogs, with links to papers from the RSPB and University of East Anglia team of conservation researchers:

There is annual management of the Berney site too, with foot-drains to be re-cut, spoil to be spread in ways that can provide a mix of water-levels and more muddy edges, and rotovation of some areas to increase the diversity of habitats. These techniques might seem rather different to the ones that are used by farmers but many of the other operations at Berney are the same as would be seen outside nature reserves, with fences to mend, stock to manage and creeping thistle and rush to ‘weed-wipe’.

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Rotovation, carried out in dry conditions, adds heterogeneity and creates bare, muddy areas

Measuring success

The development of Berney Marshes has been hugely successful. Back in 1987, there were only 13 pairs of wader breeding on the site – nine pairs of Redshank and four of Lapwing. The total for 2019 looks like being about 270 pairs – over twenty times as many.

blog RK graphRedshank: The graph alongside illustrates how Redshank numbers have changed across the decades. At the same time as Breeding Bird Survey (BTO, JNCC & RSPB) for England results revealed huge declines, with a loss of nearly half in the period 1995-2017, Redshank pairs on Berney Marshes have been increasing. Even on this site, there is a suggestion that the peak number of pairs may be in the past. Given the pressures on breeding Redshank on saltmarsh habitats (blog: Redshank – the ‘warden of the marshes’), providing breeding habitat in coastal marshes, inside sea-walls, may be particularly important. Hopefully, the latest earthworks (see later) will create more space for Redshank.

Left image below shows Redshank nest in a clump of grass. The right image shows a Lapwing nest in a newly-rotovated patch. 

 

blog L graphLapwing: Between 1988 and 1998, the number of pairs of Lapwing rose from 14 to 79, reaching a peak of 157 in 2010. Numbers vary, according to spring weather and water levels, with between 83 and 130 pairs in the years 2011 to 2019. The national decline in England was 28% between 1995 and 2017 (Breeding Bird Survey) – not quite as drastic as for Redshank but still worrying. Intensive studies at Berney have shown that productivity is only high enough to boost numbers in some years. The latest project by UEA and RSPB conservation scientists involves trialling temporary electric fences to provide protection for first clutches and broods. Hopefully Berney can become a net exporter of Lapwings in most years.

Oystercatcher: There were no Oystercatchers breeding at Berney back in 1997. The peak number of pairs was 18 in 2009, with an average of ten pairs in subsequent years. Nationally, numbers in England have increased but with major declines in Scotland, which is the species’ heartland within the UK. This is discussed in an earlier WaderTales blog.

Avocet: The RSPB’s logo species has been hugely successful, nationally, with the help of protection and habitat creation. The first pair of Avocets bred at Berney in 1992 and pairs have bred in most years since then, with over thirty pairs in nine years but no pairs in 2013 or 2014. The 2019 count is 35 pairs and there is potential for further growth in numbers across the site, with the creation of more island homes (see below).

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Combined harvesters have been replaced by nesting Avocets

Snipe: Despite all of the excellent habitat creation work, there have never been more than 8 pairs of Snipe recorded on Berney and only between 0 and 3 pairs in each of the last ten years. The underlying soils at Berney are clay-based, which may not suit this species.

Sharing the knowledge

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Redshank chick: science is an important feature of the work at Berney

Although it’s great that the RSPB has been able to buy and develop land for breeding waders in the Yare Valley, the impact of their work has been far larger, thanks to management agreements with other landowners. Mark Smart and the RSPB have set up Broads Land Management Services, to deliver wet grasslands that attract the top tier of conservation payments for farmers working in the Broads. Much of the recent work has been part of the Water Mills and Marshes Project, funded by HLF and led by the Broads Authority. Using specialist ditch-cutting and spoil-spreading equipment, the team has been able to create wet features within top-quality grazing fields. This is not just a local initiative; the kit and the advice have had impacts on farms and nature reserves across the country.

For his work for wetland conservation, Mark Smart received a Marsh Award for Wetland Conservation from the Wildfowl & Wetland Trust in 2018. “Mark Smart received his award for his 17 years managing RSPB Berney Marshes in the Norfolk Broads. Over this period, he brought together landowners, conservationists, local authorities and scientists to improve the marshes for wildlife. Today more than 300 pairs of wading birds nest there each spring, and more than 100,000 waterbirds return to it each winter.”

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Illustrations above shows work that has been completed at Somerleyton in Suffolk and a newly-fledged Lapwing.

blog DutchWorking with his wife, Jen Smart, who is a Principal Conservation Scientist at the RSPB’s centre for Conservation, Mark has added a Dutch dimension to the RSPB’s advice work by co-authoring Meadowbirds on the horizon of southwest Friesland.  This report has just been published by the International Wader Study Group.

Climate – ‘the new normal’

Fresh water is an increasingly important commodity in East Anglia – for farmers and for nature reserve wardens, looking to maximise agricultural and wader chick production. More extreme weather patterns are already producing periods of drought and intense periods of rain, while a rising sea-level is increasing the salinity of rivers and limiting extraction opportunities. Broadland farmers are looking for a reliable water supply, the Environment Agency is looking for ways to reinforce sea defences and for places to store fresh water, in order to avoid flooding, and the RSPB wants to hold more water in the late winter that can be used to keep areas wet in the early summer. With some lateral thinking, many of the needs of these key stakeholders can be met in partnership projects, as shown below

The Environment Agency’s need for material to raise sea defences provided Mark Smart with an opportunity to provide more pools and scrapes for breeding waders. It was a win-win solution; free habitat creation work for the RSPB and minimal movement of the clay and top-soil that the Environment Agency needed. In the images below, you can see this work in progress and the islands that are now being used by nesting Avocets.

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The most recent project is an ambitious water storage and flood reduction scheme for the whole of Halvergate Marsh. This will keep salt water out of these important grazing marshes and store fresh water for summer use. The £2 million Halvergate Marshes Water Level Management Improvement Scheme is a joint initiative, funded by DEFRA and delivered by the Water Management Alliance. The project involves a large number of stakeholders, including the Broads Internal Drainage Board, RSPB and neighbouring farming estates.

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The Water Level Management Improvement Scheme is a huge undertaking, with 8 km of new ditches, 240 piped culverts and 12 big sluices, that will create storage for 60,000 cubic metres of fresh water and systems to distribute this water over the course of a dry East Anglian summer. One of the most impressive features of the project, illustrating the imagination of the design team, is the Higher Level Carrier, a ‘flyover’ ditch system that passes over the top of existing wet grazing land to get water to some of the driest part of Halvergate Marshes (left picture below). This high-level water transportation route was constructed using locally-sourced clay, thereby creating shallow pools around which yet more waders are already nesting.

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When designing this project, the opportunity was taken to develop opportunities for birdwatchers to see the birds that will be drawn into the wettest areas, by making sure that the ‘best bits’ are close to public access points on the Weavers’ Way, the 61 mile (100 km) long-distance path running from Cromer to Great Yarmouth.

Aspirations

Mark Smart has not finished yet! Plans are afoot to develop the RSPB’s land that is closest to Great Yarmouth, recently purchased using a WREN grant. If agreed, this can provide an alternative, safe high-tide refuge area for tens of thousands of waders and wildfowl that roost on the mud and saltmarsh at the mouth of the Yare. Their current high-tide refuge is threatened by sea-level rise and developments proposed for the outskirts of Great Yarmouth.

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This proposed roosting area will be part of an extension to the Halvergate Marshes Water Level Management Improvement Scheme, which will add another 10,000 cubic metres of water storage. Alongside flood alleviation and fresh-water conservation, this scheme will create fifty hectares of additional shallow wader and waterfowl scrapes adjacent to Breydon Water.

blog Wood spThe new scrapes should not only attract wintering and breeding birds but also many passage waders, such as the Wood Sandpiper pictured to the right. The whole scheme has the potential to be another win-win-win-win, for the owners of low-lying properties, for Broadland farmers, for internationally important bird populations and for local and visiting birdwatchers.

Read more

Information about the RSPB’s Berney Marshes & Breydon Water reserve can be found on the RSPB’s website. Click here

There is information about the Water, Mills and Marshes project here.

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GFA in Iceland

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton

 

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Redshank – the ‘warden of the marshes’

blog nesting RKAre subsidies that are designed to protect the biodiversity of Britain’s saltmarshes, delivering the planned, conservation benefits? In particular, is this investment supporting populations of amber-listed Redshank?

About 25,000 pairs of Redshank are thought to breed in the United Kingdom (link to APEP), with about half of these nesting in coastal saltmarshes. In recognition of the importance of saltmarshes, agricultural grants are available to support their management, with a focus on providing an appropriate level of grazing for a range of plants, birds and insects. In their 2019 paper in the Journal of Applied Ecology, Lucy Mason and her RSPB colleagues ask some serious questions – are these agricultural subsidies being well spent?

Saltmarsh grazing is an important conservation prescription that is used to try to boost, or at least maintain, populations of breeding waders, particularly Redshank, as well as to conserve the unique herb-rich habitats in which they hide their nests and raise their young. This study follows on from an earlier paper that showed that more than 50% of saltmarsh-nesting Redshank in Great Britain were lost between 1985 and 2011, and three papers by Elwyn Sharps on the impacts of cattle that graze saltmarshes during the Redshank breeding season (about which there is more below).

Why worry about Redshank?

The latest population estimate for Redshank in the United Kingdom is 25,000 pairs, as many as 50% of which are birds nesting on saltings. Redshank is an amber-listed species of conservation concern in the UK, with the most recent population changes showing a drop of 44% between 1995 and 2017 (Breeding Bird Survey) and a larger decline over the period since 1990.

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What are saltmarshes?

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Rich plant communities

Saltmarshes are intricate, dynamic habitats, where land meets sea. They are highly productive ecosystems, rich in plants, birds and insects. Traditionally, they would have been grazed by herbivorous mammals and waterfowl but, in the absence of free-roaming animals, the only way to maintain the short but diverse swards favoured by specialist plants and animals is to employ the services of cattle and sheep. Although saltmarsh still covers large areas, it is estimated that over 50% has been lost or degraded globally, thanks to reclamation and erosion. Further losses are occurring, as saltmarshes get squeezed between rising sea levels and the hard sea defences that protect coastal settlements and farmland.

The structure of saltmarsh is created by the way that water moves, as waves dissipate their energy and deposit silt during higher, spring and storm tides and the water then runs back off the salting. The latter process creates branching creeks that drain the marsh, from small meandering ditches, that are just big enough to catch a foot and twist an ankle, to waist-deep, fast-flowing channels with slippery, muddy sides.

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Deep creeks of outer marsh

Anyone who has been out on a marsh will know that, with some local knowledge, it is possible to make your way from the sea-wall to the edge of the saltmarsh along a route that lies between two creek systems. On the other hand, travelling along the muddy, salting edge parallel to the sea-wall is difficult, as it involves crossing creeks. Grazing animals face the same navigation problems; it’s a lot easier to graze wide expanses of the upper marsh than the outer areas that are dissected by deep creeks. As discussed below, these upper areas, with a mixture of short grass and clumps of longer grass, are also the ones that are favoured by breeding Redshank.

How many Redshank breed on saltmarshes?

A 2013 paper by Lucy Malpas (now Lucy Mason) in Bird Study brought together evidence of declines in saltmarsh-breeding Redshank over a 26-year period. An estimated total of 21,431 pairs were found to be breeding on British saltmarsh in 1985 but this had dropped to 11,946 pairs in 2011, with the highest proportion of the remaining population found in East Anglia. The 2011 survey showed that there were regional variations (see table), with the biggest declines in Scotland. Looking at the way that saltmarshes were managed, Lucy found that Redshank declines were less severe on conservation-managed sites in East Anglia and the South of England, where grazing pressures remained low, but more severe on conservation-managed sites in the North West, where heavy grazing persisted.

tableAt the end of this Bird Study paper, Lucy and her colleagues suggest that saltmarsh-breeding Redshank declines are likely to be driven by a lack of suitable nesting habitat. Conservation management schemes and site protection, implemented since 1996, appeared not to be delivering the grazing regimes and associated habitat conditions required by this species, particularly in the northwest of England. Although habitat changes may not be linked to unsuitable grazing management in all regions, they suggested the need for a better understanding of grazing practices and consideration of potential long-term management solutions.

Grazing levels and Redshank numbers

Intensive grazing leads to a very short uniform sward, lighter grazing produces a more uneven patchy sward with diverse heights, whilst no grazing can leave saltmarshes with dense communities of coarse grasses. For Redshank, that need clumps of grass in which to hide their nests and more open areas in which chicks can feed, light grazing is a key management tool.  Elwyn Sharps and colleagues, working on the salt marshes of the Ribble Estuary in northwest England, were interested to see how grazing regimes worked for the local Redshanks. Elwyn showed that the risk of Redshank nest predation increased from 28% with no breeding-season grazing to 95% with grazing of 0.5 cattle per hectare per year, which is still within the definition of light grazing.

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In follow-up work, Elwyn showed that livestock play an important role in creating the clumps of Festuca rubra habitat preferred by Redshank nesting on the Ribble Estuary but that even low-intensity conservation grazing can create a shorter than ideal sward height, potentially leaving Redshank nests more vulnerable to predators. There is more about this in the WaderTales blog: Big Foot and the Redshank Nest.

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Grazing the higher saltmarsh

One of the missing elements from Elwyn’s first two papers about grazing levels was an understanding of the behaviour of cattle on saltmarsh. In the next piece of work, Elwyn and colleagues tracked the movements of individual cattle, using GPS collars, and assessed the vulnerability of nesting Redshank, using dummy nests. In a 2017 paper in Ecology & Evolution, they showed that cattle spend their time in the same areas of saltmarsh as the ones in which Redshanks like to nest. Their conclusion is that “grazing management should aim to keep livestock away from Redshank nesting habitat between mid-April and mid-July, when nests are active, through delaying the onset of grazing or introducing a rotational grazing system”.

Do conservation payments deliver?

To assess whether conservation grazing is being achieved, and whether agri-environment schemes are effective in delivering this management, Lucy Mason and her colleagues conducted a national survey of English saltmarshes, scoring the management on each site as optimal, suboptimal or detrimental, based on five aspects of grazing (presence, stock type, intensity, timing and habitat impact). They surveyed 213 saltmarsh sites in three regions during 2013, representing 50% of the vegetated saltmarsh in England. Of the study sites, 114 (54%) received payments for saltmarsh management and/or conservation grazing options through Higher Level Stewardship, or the Countryside Stewardship Scheme. The annual cost of saltmarsh and grazing management options in the marshes that were studied was £543,075 for 10,218 ha of saltmarsh, equating to over £5 million spent on saltmarsh management options over the course of 10 years.

blog muddy creekTo assess grazing levels, the team visited each site up to four times during the core grazing period (April–October), to count cattle. They also assessed the longer-term impact of grazing on saltmarsh habitat, by measuring sward height and heterogeneity. Combining the measurements of site condition and analysing the results produced the following key findings:

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    Nest hidden in clump of grass

    Although most saltmarsh sites in England that are capable of supporting grazing are grazed by livestock, conservation grazing is not being achieved.

  • Nationally, the biggest management failings relate to the timing of grazing and the way that grazing impacts upon habitat structure.
  • There were regional differences in scores relating to stock type, grazing intensity, grazing timing and habitat impacts, but no single region scored higher than others overall.
  • Sites with Agri-Environment Scheme (AES) agreements were no more likely to be grazed than sites without AES – some subsidies were being paid without any active grazing taking place.
  • AES reduced grazing pressure but not sufficiently to achieve optimal conservation grazing requirements, indicating that AES has been an ineffective conservation mechanism on saltmarsh.
  • In the East, older AES sites scored substantially higher and approached optimal levels, suggesting that managers and advisers can improve outcomes by working together over longer periods.

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Improving the system

The authors argue that, although there is sound scientific evidence as to how saltmarshes should be managed, to provide positive conservation outcomes, there are problems when it comes to the translation of evidence into recommendations for hands-on management. It is also difficult to encourage land managers to implement recommendations when these go against traditional farming practices and economic gain. To improve the situation, Lucy and her colleagues suggest that:

  • When establishing agreements, it is helpful to provide detailed prescriptions that can guide land-managers.
  • AES payments need to take account of the costs of grazing a complex environment, which means thinking about the availability of cattle of appropriate ages at the right times of year, provision of fresh water and high-tide refuges, and the use of fences to divide up the saltmarsh, in order to provide a rotational grazing system.
  • Prescriptions that focus on numbers of cattle and timing of grazing are easier to follow than ones that focus on intensity and habitat condition.
  • Additionally, a more detailed and reliable system of auditing would be beneficial, to ensure that management activities take place to the necessary standard prior to payments.
  • Moving to a results-based scheme, where payments are made based on desirable outcomes, rather than on evidence of management, may improve the overall conservation value and economic efficiency of saltmarsh AES options.

Blog JoshIn conclusion

Raising cattle on saltmarsh is hard work, in terms of stock control, but requires no fertiliser inputs.  These ‘mobile mowing units’ stop saltings from becoming long and rank, thereby creating spaces in which a rich plant and grass community can flourish, where geese and waterfowl can graze during the winter months, and potentially providing nesting spaces for breeding waders, such as the amber-listed Redshank, breeding numbers of which are still declining.

Lucy and her RSPB colleagues conclude that Agri-environment Schemes are the only mechanisms through which saltmarsh conservation grazing can be implemented on a national scale, so it’s important to make sure that they are as effective as possible. By working together, it is hoped that policymakers, researchers and managers can refine conservation guidelines which are used to create management schemes that attract subsidies. They suggest that better value could be achieved through more sensitive use of current management activities or perhaps by linking payments to conservation outcomes, rather than on evidence of management.

blog cr RKThe noisy warning calls of a pair Redshank, as they encourage their chicks to hide, have earned the species the title ‘warden of the marshes’. Their calls also appear to be a warning cry about the state of Britain’s saltmarshes, despite the large amount of money being provided through agricultural subsidies and the good intentions of conservation organisations, agricultural advisers and graziers.

You can read more here:

Are agri-environment schemes successful in delivering conservation grazing management on saltmarsh? Lucy R. Mason, Alastair Feather, Nick Godden, Chris C. Vreugdenhil & Jennifer Smart. Journal of  Applied Ecology. May 2019.

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GFA in Iceland

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton

Ireland’s wintering waders

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There’s still space for a few Knot

The island of Ireland is a great refuge for wintering waders, washed as it is by the warm waters of the Gulf Stream. It’s just a quick hop across the Atlantic from Iceland for Black-tailed Godwits, Golden Plovers, Redshanks and Oystercatchers. For birds travelling from Siberia, such as Bar-tailed Godwits and Grey Plovers, it’s a longer journey but one that’s well worth making.

If Ireland is such a great destination for shorebirds, why do the latest population estimates reveal a decline of nearly 20% in wader numbers in just five years?

This blog summarises the wader information, published in Estimates of waterbird numbers wintering in Ireland, 2011/12 – 2015/16 in Irish Birds. The totals in the report are split into counts for the Republic of Ireland and Northern Ireland but, given that waders don’t recognise borders, most of the comments in this blog relate to the whole of Ireland. The results for 2011-16 have been compared to the equivalent figures for 2006-11 and set in the context of the totals of wintering waders throughout the East Atlantic flyway, as combined by Wetlands International. The Irish data were collected by the amazing volunteers who make monthly, winter counts for I-WeBS (BirdWatch Ireland & National Parks & Wildlife Service) and WeBS (BTO/RSPB/JNCC in Northern Ireland).

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Headline figures

Fifteen species are considered in this report. The most numerous are Lapwing and Golden Plover, which account for an estimate over 170,000 individuals between them, whilst the smallest contributions are made by Purple Sandpiper (662) and Greenshank (1317). In total, the average estimated number of waders in the winters during the period 2011-16 is 429,170 birds but it should be noted that this total excludes two widespread and common species – Woodcock and Snipe – as well as the enigmatic Jack Snipe. To update previous estimates for these three species, which were last made using distribution and abundance data collected during Bird Atlas 2007-11 fieldwork, it would be necessary to run a special inland survey. There is also some question about Lapwing and Golden Plover numbers, simply because so many of these birds are found in areas that are not covered by monthly waterbird counts.

Biggest changes

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The Irish Sanderling population has increased by 13.2% in five years

The combined average winter maximum count of the 15 wader species examined in the report declined by 102,310 birds (19%) in the five-year period between 2006-11 and 2011-16. This is extremely worrying. If Lapwing and Golden Plover are excluded from consideration, as there is uncertainty about the completeness of counts, there are five species that are of particular concern; Knot numbers dropped by more than 40% and Oystercatcher, Dunlin, Redshank and Turnstone numbers by more than 20%. The Purple Sandpiper population estimate dropped by over 30% but relatively small numbers of this species are encountered around the rocky coast of Ireland. The only species to show increases were Sanderling, Bar-tailed Godwit, Black-tailed Godwit and Greenshank.

In a previous WaderTales blog, there is detailed information about population estimates for Great Britain: Do population estimates matter? In Great Britain there were similar rates of decline for Redshank and Turnstone (measured over an eight-year, rather than five-year period) but much smaller falls for Knot, Oystercatcher and Dunlin. The possible causes of the changes in Ireland are discussed in the paper in Irish Birds. They include flyway-scale declines (e.g. Knot and Curlew) and the possibility that more birds from the east are now wintering on the coasts of mainland Europe (e.g. Dunlin and Grey Plover).

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European context

Blog tableThe table alongside gives an indication of the relative importance of Ireland, Great Britain and, together, the British Isles to the birds that use the East Atlantic flyway during the winter period. The three columns show the percentage of each species found in each of the three regions. Summarised international counts, as used in the paper, were kindly provided by Wetlands International. In the case of four species, Ireland is host to a significant proportion of the Icelandic breeding population (Oystercatcher, Golden Plover, Black-tailed Godwit and Redshank).

Notes: As mentioned earlier, there are questions about the precision of estimates for Lapwing and Golden Plover, although the population trends are reliable. The Ringed Plover percentage seems high (98% for British Isles) but this may well reflect the fact that the Non-estuarine Waterbird Survey has uncovered significant numbers of the species on the open shores of Great Britain. These extra birds are included in the new totals for GB but not in the flyway total. The percentages for Black-tailed Godwit seem low, as discussed further down.

Ireland is particularly important for Golden Plover, Ringed Plover, Bar-tailed Godwit and Black-tailed Godwit, as well as for the Icelandic subspecies of Redshank. Greenshank is excluded because the percentages are below 1% of the flyway population for Ireland and for Great Britain.

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11% of Bar-tailed Godwit on the East Atlantic Flyway spend the winter in Ireland

Although there are important populations of breeding waders in Ireland, the shores and wet fields of the island really come into their own during July and August, when the first ‘winter’ waders arrive, and they only become quiet again in April and May, when the last birds head north and east to nest. A successful breeder is likely only to be away for four or five months, meaning that these waders will spend by far the largest part of the year in Ireland. The island is even more important for immature birds. Young Oystercatchers that arrive from Iceland, Scotland or perhaps Norway when just a few months old are likely to spend the next 30 months in Ireland before making their first trip north. There is a WaderTales migration blog about the Oystercatchers that fly from Iceland: Migratory decisions for Icelandic Oystercatchers.

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Curlew in the Republic

Curlew numbers in the Republic of Ireland illustrate the relative importance of the country for breeding and non-breeding populations. The winter population estimate for Curlew in the Republic is 28,300 but the most recent survey conducted by BirdWatch Ireland and NPWS, as summarised in the WaderTales blog Ireland’s Curlew Crisis, reveals that the number of breeding birds has crashed to just 138 pairs. Accounting for young Irish birds that have not started to breed, and even if we assume that all Irish birds stay in the country for the winter, then the total number of home-grown Curlew seen in non-breeding flocks is at most about 400. This means that every winter flock of 70 Curlew will contain an average of just one Irish bird. Far more deliver their curl-ew calls with a Scottish, Finnish or Swedish ‘accent’. The map below shows the migration pattern for Curlew ringed in or found in Britain & Ireland.

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Black-tailed Godwit

In the table above, it looks as if 18% of Iceland’s Black-tailed Godwits spend the winter in Ireland. This is probably an underestimate of the importance of the Republic of Ireland and Northern Ireland to the species. The flyway total for Black-tailed Godwit is given as between 98,000 and 134,000 in the Irish Birds paper and the percentage figure is based on 110,000. These three figures are almost certainly too high, as they build upon country-based estimates that have subsequently been revised. The true figure is likely to be around 60,000 to 65,000 (J. Gill pers. comm.), which would suggest that the maximum winter count in Ireland of 19,800 represents at least 30% of the islandica Black-tailed Godwits. Add in extra birds that moult in Ireland in the autumn, before moving further south to countries such as Portugal, and other birds that spend spring months on the island, and Ireland becomes even more important for Black-tailed Godwits!

blog BTMost birdwatchers might associate flocks of waders with estuaries but Black-tailed Godwit is an excellent example of a species that also relies on inland fields, either close to estuaries or along river valleys. Whilst undertaking PhD research on Black-tailed Godwits in south-east Ireland, Daniel Hayhow showed that there is insufficient time to find enough estuarine food during the mid-winter tidal cycles, with birds topping up their resources on grassland. You can read more about the energetic consequences of choosing to winter in eastern England, Portugal and Ireland in this blog: Overtaking on migration. Site designation and planning decisions need to take account of the grassland feeding requirements of Black-tailed Godwits and other waders that do not spend all of their time on estuaries, particularly Curlew.

Conservation implications

Some of the issues facing waders may be related to threats that species face in the breeding grounds. However, it may be easier to introduce measures that provide better protection and feeding opportunities in the wintering area, as ways of maintaining populations through the non-breeding season, than it is to deal with problems in the High Arctic. (Although we can all help by reducing carbon emissions, in order to minimise global warming, of course).

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Reading the report, I was reminded of the need to consider a range of conservation issues:

  • Care needs to be taken when considering shoreline developments. These can directly remove habitat or squeeze the width of the intertidal zone.
  • Increased harvesting of shellfish can affect species such as Oystercatcher and Knot and brings risks of introducing alien species and diseases.
  • In the drive to cut carbon emissions, tidal, wave and wind power developments need to be sited in appropriate places.
  • Off-shore harvesting of growing kelp beds has been suggested, as a way of producing fertiliser and biofuels. This process could reduce protection for beaches and change the availability of resources for species such as Turnstone and Sanderling.
  • Grassland areas need to be considered (and not just estuaries) when planning protection for species such as Curlew and Black-tailed Godwit.

blog RKPaper

Estimates of waterbird numbers wintering in Ireland, 2011/12 – 2015/16. Brian Burke, Lesley J. Lewis, Niamh Fitzgerald, Teresa Frost, Graham Austin, and T. David Tierney. Irish Birds No. 41, 1-12.

There is a complementary paper in British Birds, covering Great Britain. The wader information is summarised in this blog: Do population estimates matter?


GFA in Iceland

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton

Do population estimates matter?

blog top godwitsThis month (March 2019) saw the publication of Population estimates of wintering waterbirds in Great Britain, which includes all the wader species from Little Stint to Curlew. Given that the Wetland Bird Survey already covers about 2000 wetlands and provides annual monitoring, why do we need to know the total number of birds in Great Britain?

I suggest four reasons:

  • If we count the number of Curlew and we have a figure for the European population then we know that Great Britain is responsible for nearly 20% of Europe’s Curlew each winter, thereby strengthening the case for national conservation action;
  • If we have a national figure, then we know that a flock of 2000 Black-tailed Godwit represents (as it turns out) over 5% of the British total, which is a useful criterion when assessing the conservation importance of individual sites;
  • blog GKPopulation totals help to put annual percentage changes into context;
  • And simply because people ask questions such as “how many Greenshank are there in the country during the winter?”

So, here’s the bottom line. In their 2019 review of waterbird numbers in British Birds, a team from BTO, WWT, JNCC & RSPB reveal that an estimated total of 4.9 million waders spend the winter in Great Britain. That’s about one third of all waders on the East Atlantic Flyway. Impressive!

Please note that Northern Ireland figures are included in an upcoming report for the island of Ireland.

Making the counts

The population estimates owe a lot to those who undertake monthly Wetland Bird Survey (WeBS) counts on estuaries, lakes and waterways, during the winter months, year in and year out. Counts from the period 2012/13 to 2016/17 are used in the population estimates that form the basis for the 2019 review. WeBS data have many other uses, as you can read here: Wetland Bird Survey: working for waders.

blog CUFor species of wader that also make use of the open coast, the Non-estuarine Waterbirds Survey of 2015/16 (or NEWS III) provided additional data, updating the NEWS II figures from 2006/07. The vast majority of our wintering Purple Sandpipers are found on open beaches and rocky shores, as well as large numbers of Turnstone, Ringed Plover and Sanderling, together with significant numbers of Oystercatcher, Curlew and Redshank. There’s more about NEWS in this slightly dated blog: NEWS and Oystercatchers for Christmas.

The last assessment of winter wader populations was made by the Avian Population Estimates Panel and published in British Birds in 2013 as Population estimates of birds in Great Britain and the United Kingdom (APEP3). In here, estimates for waders were largely based on WeBS data for the period 2004-09 and NEWS II. The new assessment is presented as Population estimates of wintering waterbirds in Great Britain and also published in British Birds. It uses WeBS information for the period 2012-17 and NEWS III data. Effectively, there is an 8-year or 9-year difference between the two sets of figures.

The biggest losers

blog graphicGreat Britain is extremely important in the context of the East Atlantic Flyway, as is obvious from the fact that the area holds nearly five million waders. The WeBs counts already monitor the ups and downs on an annual basis but this review provides an opportunity to turn the percentages into actual numbers. It is concerning that, over a period representing less than a decade, the average maximum winter count for six of the species that were surveyed dropped by a total of over 150,000. These big losers were Knot, Oystercatcher, Redshank, Curlew, Grey Plover and Dunlin, ordered by number of birds lost, with Knot seeing the biggest absolute decline.

In preparing the new estimates for the British Birds paper, an opportunity was taken to refine the way that populations are calculated, based on Use of environmental stratification to derive non-breeding population estimates of dispersed waterbirds in Great Britain, by Verónica Méndez et al. The new methodology explains some of the differences between percentage changes reported by WeBS and the percentage changes obtained by comparing the latest population estimates to those in APEP3.

blog KN graphic

The Knot estimate dropped from 320,000 to 260,000. This figure is higher than might be expected from the counts that take place at sites covered by WeBS, being larger than the ten-year decline of 14% reported in the last WeBS report. Knot are mobile species within the North Sea and Atlantic Coast wintering area and it is possible that British losses may be explained, at least to some extent, by redistribution.

blog oyc graphThe drop in Oystercatcher numbers from 320,000 to 290,000 appears to be less than 10%, compared to a ten-year decline of 12% on WeBS. Improved analysis of NEWS data helped to add some more birds to the open-coast estimate so the 10% fall may underestimate the seriousness of the Oystercatcher situation. The 25-year Oystercatcher decline on WeBS is 26%, which is not surprising if you look at the changes to breeding numbers in Scotland, where most British birds are to be found. There’s more about this in: From shingle beach to roof-top.

blog RKThe Redshank decline of 26,000 is higher than would be predicted from WeBS figures, suggesting a drop of over 20% since APEP3, rather than ‘just’ 15% for the ten-year WeBS figure. This is a species that also features strongly in the Non-estuarine Waterbird Survey and that might explain the difference. Wintering Redshank are mostly of British and Icelandic origin, with the Breeding Bird Survey (BBS) suggesting a ten-year decline of 24% in our British breeding birds.

The Curlew is now globally recognised as near-threatened. The latest winter estimate is 120,000, down from 140,000 in APEP3. The new total represents between 14% and 19% of the European population, which means that we have a particular responsibility for this much-loved species. Only the Netherlands holds more wintering Curlew than Great Britain. Is the Curlew really nearly-threatened? is one of several blogs about Curlew in the WaderTales catalogue at www.wadertales.wordpress/about .

blog 2 DNIt has been suggested that the long-term declines of Grey Plover and Dunlin  may be associated with short-stopping, with new generations of both species wintering closer to their eastern breeding grounds than used to be the case. WeBS results indicate a 31% drop in Grey Plover and a 42% drop in Dunlin, over the last 25 years. There was a loss of 10,000 for both species between APEP3 and the new review, representing declines of 23% and 3% respectively.

The biggest winners

There are four big winners in the period between APEP3 (2004-09) and the new review (2012-16), although, even here, not all as it seems.

The Avocet has seen further dramatic gains. with the estimated wintering population rising to 8,700. The increase is not quite as big as might have been expected, based on the 43% rise seen in ten years of WeBS counts, but it is still a dramatic continuation of a 40-year trend.

The numbers of Bar-tailed Godwit and Ringed Plover are both substantially higher but at least a proportion of each of these changes is linked to the better coverage and more sophisticated sampling methods that were discussed earlier. Bar-tailed Godwit increases may also reflect redistribution around the North Sea.

blog BW graphOne of the consequences of improved statistical techniques, as used this time around, is the apparent decline in the estimated population of Black-tailed Godwit. The new figure of 39,000 is 4,000 smaller than in APEP3, despite the fact that the WeBS graph clearly shows an increase. Interpolation using WeBs figures suggests that the earlier population estimate should have been 31,000, rather than 43,000.

There are other winners too, as you can read in the paper. At the start, I posed the question “how many Greenshank are there in the country during the winter?”.  The answer is 810, representing an increase of 200 since APEP3.

Game species

The estimates for the three wintering waders that are still on the UK quarry list have not changed since APEP3 (published in 2011) as there are no new data available.

Golden Plover: The winter estimate remains as 400,000, as there has been no comprehensive, winter survey since 2006/7. Large numbers of Golden Plover arrive from Scandinavia, Europe and Iceland in the late summer, joining the British birds that choose not to migrate south or west. The GB breeding population is probably less than 50,000 pairs. Most breed in Scotland which has seen a breeding decline of 23% in the period 1995 to 2016 (BBS). Golden Plover is still ‘green listed’.

snipe-headerSnipe (Common): The winter estimate remains as 1,100,000 – a figure that was acknowledged in APEP3 as being less reliable than that of most species. At the same time, the GB breeding population was estimated as 76,000 pairs, indicating at least a 4:1 ratio of foreign to British birds, and that does not take account of the number of British birds that migrate south and west. Snipe are ‘amber listed’ but BBS suggests a recent increase of 26% (1995-2016). There is a WaderTales blog about  Snipe and Jack Snipe.

Woodcock: The winter estimate remains as 1,400,000 – another figure that is not considered to be particularly precise, with much variation between years. The diminishing breeding population is dwarfed by winter numbers, as you can read in this WaderTales blog, with increased attention being given to ways to afford better protection of red-listed, British-breeding birds.

January counts

blog BTThe paper in British Birds also includes a table of January population estimates, to provide data that are comparable to mid-winter counts in other countries. These figures are used in waterbird monitoring for the International Waterbird Census for the African Eurasian Flyway. The main table (and figures mentioned above) are average maximum winter counts (in the period September to March). Black-tailed Godwit is one species that illustrates the difference, with a mean of 30,000 in January and a mean peak count of 39,000. Having moulted in Great Britain, some Black-tailed Godwits move south to France and Portugal in late autumn, returning as early as February. January counts are therefore substantially lower than early-winter and late-winter counts. There is more about the migratory strategy employed by Black-tailed Godwits that winter in southern Europe in Overtaking on Migration.

Looking forward

blog BB coverThe authors have done a tremendous job. They have refined the way that estimates are calculated, they have combined the results from WeBS and NEWS III, and they have delivered population estimates for 25 wader species and many more other species of waterbirds. These population estimates will be used in conservation decision-making until the next set of numbers becomes available. Meanwhile, thousands of birdwatchers will count the birds on their WeBS patches in each winter month, every year. Without them, this paper could not have been written.

Before the next assessment, there will need to be another NEWS survey, to check up on species that use rocky and sandy shore birds, such as Purple Sandpipers, Turnstone and Curlew. Hopefully, there will also be a dedicated survey to assess Lapwing and Golden Plover numbers and perhaps we might find a way to refine the old estimates for Woodcock, Snipe and Jack Snipe.

Paper

Population estimates of wintering waterbirds in Great Britain. Teresa Frost, Graham Austin, Richard Hearn, Stephen McAvoy, Anna Robinson, David Stroud, Ian Woodward and Simon Wotton. Published in British Birds Volume 112. March 2019.

British Birds is a subscription journal. The issue containing this paper can be purchased separately. At some stage, the paper will become free-to-view.

blog flying godwits

 


GFA in Iceland

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton

The waders of Northern Ireland

blog CU postNorthern Ireland is a great place for wintering waders but the same can no longer be said for its breeding species. There are far too few places left in which Curlew bubble and Snipe drum.

Waders provide some of the best birdwatching spectacles in Northern Ireland, as flocks swirl around coastal estuaries, when the tide rises on a winter’s day. Birds fly in from as far away as Canada and Russia but there are particularly strong links to Iceland, about which there will be more later. Every year, winter counts by volunteers, who help with the Wetland Bird Survey, alert us to the ups and down in wintering populations on loughs and estuaries. Unfortunately, we know much less about breeding species such as Lapwing, Redshank, Snipe and Curlew – four species that feature in a new Northern Ireland survey in the summer of 2019. Although the annual Breeding Bird Survey monitors birds such as Song Thrush and Willow Warbler, waders are just too thinly spread in Northern Ireland for it to be possible to pick up any year-to-year changes. That’s why they need a special survey.

blog L flightWe know that there were some great wader hot-spots in the years 1985 to 1987, when a major Northern Ireland survey took place, and that large drops in numbers were reported in 1999 and again in 2013, after other dedicated surveys, but what is happening now? Are there still places where Snipe drum and Curlew bubble? The BTO in Northern Ireland is asking local and visiting birdwatchers to revisit some of the best places that were identified in previous surveys, to look for breeding waders and to assess the habitats that remain. This work complements work being undertaken by RSPB Northern Ireland. If you think that you may be able to help click here to find more information.

Not looking good?

Although it would be nice to be proved wrong, the expectation is that breeding wader numbers will have declined still further. This means, of course, that any remaining sites that still hold species such as Redshank and Lapwing, are going to be even more important than they were thirty years ago. Pessimism is based on trends elsewhere; numbers of breeding waders are falling throughout the UK and increased agricultural intensification within the Republic of Ireland has caused sharp declines in the focal species of this survey – Lapwing, Redshank, Snipe and Curlew. The following notes give some highlights about Northern Ireland’s waders and point out some of the things that we don’t know (yet).

Lapwing

blog Lap mapThe Lapwing has quietly disappeared from much of Northern Ireland over the last fifty years. The black triangles in the map alongside represent 10-km squares that lost their breeding Lapwings between the two atlases of 1968-72 and 2008-11. Previous Northern Ireland surveys of breeding waders in 1985-87 and 2013 suggest that the number of pairs dropped from an estimated total of 5250 to a total of 860 – that’s a loss of 5 out of 6 pairs. The new survey this summer will update breeding numbers in the species’ heartland areas, as long as sufficient volunteers step forward to help with coverage. (Here’s a link to the results of the 2013 Northern Ireland wader survey.)

Redshank

blog RKThere is no recent estimate for the number of breeding Redshank in Northern Ireland. Across the UK, the Breeding Bird Survey suggests that we have lost 41% of breeding birds since 1995, and the decline was well underway by then. The survey this year provides a good opportunity to learn as much as possible about this threatened species.

In the late summer, the tiny Northern Ireland population is joined by Redshank from Iceland and Scotland. There are also small a number of movements linking Northern Ireland with Wales and England; some of these might be of birds from further east in Europe that were ringed in Britain. Strangford Lough peak counts of over 2000 in October illustrate just how much of an influx there is each autumn.

Snipe

blog SN mapThe lowland wader survey in 1985-87 suggested that the Northern Ireland population of Snipe was about 5725 pairs. By the time of the next survey in 1999, that number had dropped to 3993 and then to 1123 in 2013. That’s a drop of 80%. Snipe seem very sensitive to habitat change, especially drainage. The map alongside shows the change in abundance between 1988-91 and 2008-11 across Britain & Ireland. There is an interesting mix of losses (grey) and increases (orange) in Northern Ireland. It will be great if the 2019 survey picks up some new Snipe hot-spots. One of the key elements of the fieldwork this year is to record habitat data and field-use. What habitats do Snipe still breed in and can these be expanded and replicated elsewhere within Northern Ireland?

blog SN groundThere’s a WaderTales blog about Snipe & Jack SnipeMany of the birds that are seen in Northern Ireland in the winter have flown across the Atlantic to escape the snow and cold of Iceland but there are also large numbers from Scandinavia and continental Europe

Curlew

The Curlew is in huge trouble across the whole island of Ireland. Surveys of random squares in 1985-87, 1999 and 2013 suggest that the number of breeding pairs in Northern Ireland dropped from 5000 to about 500 over the period. There is talk about potential extinction as a breeding species in Ireland and Wales. This may seem ridiculous when you can see flocks totalling 2000 birds around Lough Foyle, on a winter’s day. However, these are almost exclusively migrants, from Finland, Scandinavia and Scotland. One of the hopes is that the new survey will pinpoint new hot-spots for Curlew. There is already concerted action to try to bolster numbers through the Lough Erne Landscape Partnership.

blog CU box

Other Northern Ireland waders

Oystercatcher: Many wintering Oystercatchers leave Northern Ireland in the spring, heading for Iceland, Scotland or perhaps Norway (more in this wader migration blog). By that time, resident adults will already have moved inland or onto beaches to breed and other birds will have returned from southern wintering areas.

blog RPFlocks of young birds are found on estuaries in the summer, as Oystercatchers typically don’t breed until three years old. We know that the number of breeding Oystercatchers in Scotland dropped by 38% between 1994 and 2017 but English numbers rose by 49% (read more here). We don’t know what’s happening in Northern Ireland.

Turnstone: Wintering birds are mostly thought to come from Greenland and Canada but a December capture of a bird from Sweden suggests that there might be a link to the east as well.

Ringed Plover: The new survey in Northern Ireland is not designed to monitor beach-nesting Ringed Plover. The most recent UK-wide survey of the species was in 2007, when the Northern Ireland population estimate was 147 pairs, similar to the estimate at the time of the previous survey, in 1987. In the same period, numbers dropped in Scotland (-42%) and England (-29%). Link to summary of paper.

blog GP mapGolden Plover: Ireland is a winter destination of choice for many Golden Plover that breed in Iceland. The recovery of a Belgian-ringed bird in 2006 suggests that some birds may arrive from the east as well. Wintering numbers are half what they were 25 years ago, according to WeBS data for Northern Ireland. A few breeding birds can still be found in the western parts of Northern Ireland but they have been lost from most other areas.

Grey Plover: It’s a long way from Siberia to Northern Ireland, so perhaps it is not surprising that not many Grey Plover make it this far west!

Knot: The best place to see Knot is in Strangford Lough, where numbers peak at over 4000 in some winters. The only two foreign-ringed birds were shot wearing Icelandic rings in 1957 and 1975 (when shooting them was legal). Northern Ireland’s wintering Knot probably breed in Greenland or Canada and migrate via Iceland.

Sanderling: The Sanderling that are seen around the coast in winter months, in small numbers, will almost certainly breed in Greenland. Numbers are higher in spring, when birds from further south stop off on their way to Iceland and then Greenland.

blog DN

Dunlin: This year’s survey of Lapwing, Redshank, Snipe and Curlew should really include Dunlin, as they share similar breeding habitat. However, it will be a very lucky volunteer who finds a displaying adult. Birds of the schinzii (green arrows) and arctica (yellow) race pass through in spring and autumn but the wintering birds are of the alpina race (orange).

blog WK mapWoodcock: The black triangles in the map opposite show the parts of Northern Ireland that have lost breeding Woodcock in the last 50 years. Data are from Bird Atlas 2007-11 (BTO, BirdWatch Ireland & SOC). In late autumn, birds fly in from counties such as Germany, Norway and Russia. See this blog.

Black-tailed Godwit: All is not gloom and doom in the world of waders; there are six times as many Black-tailed Godwits wintering in Northern Ireland as there were 30 years ago. Great views of these Icelandic visitors are provided at the RSPB reserve at Belfast’s Window on Wildlife. This blog explains why numbers have taken off in recent years.

Bar-tailed Godwit: The Bar-tailed Godwit that are seen in Strangford Lough and elsewhere are birds from northern Norway and Russia. There seems to have been little change in numbers, according to Northern Ireland WeBS counters.

blog Whimbrel box

Whimbrel: A few Whimbrel drop in during autumn passage but far more appear in spring. Most Icelandic Whimbrel can fly straight to West Africa in the autumn but 80% stop off on the way north, many in Northern Ireland (see graphic above). You can read more here.

From Avocet to Pectoral Sandpiper

There is a supporting cast of waders that visit Northern Ireland. This blog provides more information on wader migration: Which wader, when and why?

A call for help

blog habitatAs must be obvious by now, BTO Northern Ireland is looking for volunteers to help with wader surveys in 2019. Sites are discrete lowland wet grassland areas, small enough to survey in one morning. At least two or ideally three visits to each site are required between mid-April and mid-June, with at least two weeks between each visit.

Each field or sub-unit needs to be covered on foot and the number of Lapwing, Curlew, Redshank and Snipe are counted per field. Some additional habitat recording is required, e.g. recording grazing, rush cover and estimating dampness.

blog mapSites are located in five broad areas (see map):

  • Loughs Neagh and Beg
  • Blackwater Catchment
  • Tyrone Fairy Water Bogs
  • Upper Lough Erne
  • Lower Lough Erne (these sites will be covered by the RSPB)

More details are available here, on the BTO Northern Ireland website. There will be a free training session on 29 March. Contact shane.wolsey@bto.org if you have any questions or would like to volunteer.

blog CU banner


GFA in Iceland

Graham (@grahamfappleton) has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland. He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.

 

Designing wader landscapes

blog whimbrelMuch has been written about the negative impacts of agriculture on breeding birds – but farming can be good for some species. In Iceland, where high-input agriculture is relatively recent, breeding waders are commonly found in nutrient-rich environments that are associated with increased production. How can high breeding densities of waders be maintained, as farming continues to expand and intensification increases?

In her paper in Agriculture, Ecosystems & Environment Lilja Jóhannesdóttir investigates the distribution of breeding waders across landscapes with varying amounts of highly-cultivated fields and semi-natural areas. She discovers that, in some circumstances and at an appropriate level, adding cultivated land within a broader mosaic of habitats may benefit breeding waders. Is this a model system that provides clues as to how to design landscapes that can support sustainable breeding wader populations in other parts of the world?

The waders of Iceland

table

Breeding populations of waders in Iceland (AEWA report)

Iceland is a hot-spot for breeding waders, holding half or more of Europe’s Dunlin, Golden Plover and Whimbrel, in a country that is a bit smaller then England. The paper at the heart of this blog is written by Lilja Jóhannesdóttir, who worked with colleagues from the University of Iceland, the Agricultural University of Iceland, the University of East Anglia (UK) and the University of Aveiro (Portugal). They investigated how different ways of increasing agricultural productivity might impact upon these species, and others such as Black-tailed Godwit, Redshank and Snipe.

Much of Iceland’s upland interior is not suitable as farmland but there is still plenty of room for agricultural expansion. Only 7% of the area between sea level and an elevation of 200 m is currently under cultivation but it is estimated that it would be possible to increase this to 63% – an eight-fold extensification. Icelandic lowlands currently comprise a fine-scale mosaic of open semi-natural habitats and cultivated fields (primarily for silage production to feed animals), making most of the landscape much more heterogeneous than in countries with a longer history of commercial farming.

blog hay and semi-naturalTwo previous WaderTales blogs have already shown that:

Given that farm production is predicted to increase, that farmers like breeding waders and that some intensively-managed fields can be attractive to waders, is it possible to design farmed landscapes that will work for birds and farmers?

Increasing inputs and reducing heterogeneity

blog nice wetlandGlobally, the expansion and intensification of agriculture has altered landscapes and the associated homogenisation has greatly influenced bird abundance and reduced biodiversity. Populations of numerous species, particularly specialist species, have declined, as agriculture has expanded, while generalist species have often thrived in agricultural habitats.

There is no shortage of examples in which highly intensively managed farmland is shown to be bad for breeding waders. In the monoculture hay-meadows of the Netherlands, Black-tailed Godwit productivity is really low, for instance. These fields have been drained, fertilised and re-sown, in order to create easily-managed carpets of single-species grass that can be cut several times a year. There is more about this in this paper by Roos Kentie.

blog hay fieldAlthough there are some areas of Iceland in which farming is quite intensive, there are many others where farmers have a lighter touch. For instance, nutrient-poor dwarf birch marshes may occasionally be grazed by sheep in the summer but these areas have never received applications of artificial fertiliser. At this end of the intensification continuum, increasing agricultural operations may have benefits for breeding waders. When a patch of rough grazing is ploughed and turned into a hay meadow, the addition of fertilisers can potentially increase soil fertility and create an attractive place for waders to feed. A hay meadow within a local area that is dominated by dwarf birch marsh could effectively increase the heterogeneity (& nutrient-richness via spill-over) of the local area, albeit in an artificial way. In the UK, Golden Plovers breeding on moorland are known to travel up to 7 km to feed on fertilised hayfields with high earthworm densities. This paper by James Pearce-Higgins & Derek Yalden in IBIS provides a nice example of how low intensity agriculture can provide resources for waders in the wider landscape.

Researching waders and landscapes

blog dbmLilja’s work in the Southern Lowlands of Iceland focused upon understanding how agriculture influences breeding wader densities and how these relationships might influence future change. At its heart were counts of adult waders encountered along 200 transects (totalling over 100 kilometres) within semi-natural habitats, visited at several stages during the breeding seasons of 2011 and 2012.

As well as counting birds, Lilja categorised habitats within 500, 1000, 1500 and 2500 metres of the transects, which she called buffer area in the paper. Interestingly, and usefully for later analyses, the distribution of different habitat types is pretty uniform across these scales, in this part of Iceland, with little substantial difference according to elevation. In the diagram below, the 200 transects (a) have been split between those below 50 m above sea level (b) and those higher than 50 m (c).

buffers

Landscape-scale effects

To fulfill the various demands of parents and their offspring, waders need diverse resources on or near their territory. An adult can feed a kilometre or more away from its nest, between incubation bouts, and chicks are mobile from an early age. Tagging has shown that young Black-tailed Godwits can move up to 3 km in the first five days of life, just to give one example. In this open landscape, breeding success is likely to be a function of habitat availability at a broad scale. This is explored in a WaderTales blog about nesting Whimbrel.

blog redshankUsing data collected from these 200 lowland transects, Lilja was able to establish relationships between breeding wader densities and the amount of cultivated land and wetland in the surrounding landscape. These two habitat types were considered because future agricultural expansion is likely to take place on drained wetlands that have high conservation value. In her analyses she assessed the extent to which the amount of cultivated land in the surrounding landscape affects wader densities on semi-natural land, and then considered the potential effects of future agricultural expansion on wader populations. There was substantial variation in the density of all of the six most common wader species recorded on the transects, ranging from 0 to 284 birds/km2.

Lilja found that wader densities in semi-natural habitats were consistently greater when the surrounding landscapes had more wetland, at scales ranging from 500 m to 2500 m, indicating the importance of wetland availability in the local neighbourhood. However, the effects of cultivated land in the surrounding landscape varied with fertility and landscape structure, which was largely defined by altitude.

  • In fertile, low-lying coastal areas (from sea-level to 100 m altitude), wader numbers declined with increasing amounts of cultivated land (and the lowest densities occurred in areas dominated by cultivation). This suggests that further conversion of semi-natural habitats into farmland is likely to severely impact waders in low-lying areas.
  • In less fertile habitats at higher altitudes (between 100 m and 200 m), the lowest densities occurred in areas without cultivated land. This suggests that additional resources provided by cultivated land may have a more positive affect in the less-fertile, higher altitude areas.

blog blackwitThe relationships between the areas of wetland and agriculture in the surrounding landscape and the density of waders vary between species, as you can read in some detail in the paper. A few highlights are:

  • With increasing area of cultivated land, densities of Golden Plover, Dunlin and Whimbrel declined significantly at lower altitudes but increased at higher altitudes. These are the three species that would appear to respond most positively to the addition of pockets of cultivated land within a semi-natural matrix of less fertile land, that tends to be found at higher elevations.
  • Higher amounts of wetland were associated with increased densities of Dunlin and Black-tailed Godwit, but lower densities of Redshank. Golden Plover numbers were unaffected by amount of wetland in the surrounding landscape.
  • Whimbrel densities increased with wetland area, at higher altitudes. Wet patches have been shown to be very important to Whimbrel chicks, as you can read in this WaderTales blog about research in Shetland.
  • At lower altitudes, Snipe densities increased with the amount of wetland area in the local vicinity. This relationship was less pronounced at higher altitudes, which tend to be less effectively drained and hence generally wetter.

dunlin graphic

What now?

Changes in Icelandic landscapes are to be expected in the coming years, as most farmers intend to increase their areas of cultivated land. This expansion will inevitably have impacts upon the internationally important breeding wader populations of Iceland but the level of such impact will depend on where the expansion will occur. This paper shows that increases in the area of cultivated land at lower altitudes in Southern Iceland are more likely to result in declines in wader density than in less fertile areas, when tend to occur at slightly higher altitudes (still under 200 m above sea level). An important next step will be to identify the landscape structures and scales of management that can continue to support high densities of breeding waders.

blog coastal wetlandGiven the international importance of Iceland as a home for breeding waders it would be nice to think that this paper can be used to develop national land management policies that can prevent the unintended loss of species such as Golden Plover and Snipe, which landowners value and wish to preserve. At the farm and community level, the paper highlights the key importance of maintaining the complex and heterogeneous landscapes of lowland Iceland, retaining as many as possible of the remaining wetland patches and pockets of semi-natural land within even the most intensive of farming areas.

The paper may well be of interest to conservationists who are struggling to reverse wader declines in other parts of the world. In Southern Iceland, where 7% of the land is being farmed relatively intensively within a fine scale mosaic of both wet and dry semi-natural habitats, it is possible to support hundreds of waders per square km across the wider countryside. Can this situation be replicated across large tracts of land in other countries?

Take home message and paper

blog heterogeneousThis paper provides a useful reminder that the links between land use changes and biodiversity implications can be highly context-dependent. Further agricultural conversion of wetlands and rough grazing areas in the fertile low-lying areas of Iceland is likely to be detrimental for breeding waders, but such effects may be less apparent in less fertile, higher altitude areas. Here, the conversion of some land from rough-grazing to hay meadows may provide feeding opportunities off-territory for Dunlin, Golden Plover and Whimbrel. The scale at which the addition of cultivated areas is beneficial to breeding waders has yet to be determined.

This paper is published as:

Interacting effects of agriculture and landscape on breeding wader populations. Lilja Jóhannesdóttir, Jennifer A. Gill, José A. Alves, Sigmundur H. Brink, Ólafur Arnalds, Verónica Méndez and Tómas Grétar Gunnarsson https://doi.org/10.1016/j.agee.2018.11.024

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GFA in Iceland

Graham (@grahamfappleton) has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland.  He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.

 

Tool-kit for wader conservation

andyhayDecades of drainage and agricultural intensification have caused huge declines in numbers of breeding waders in the lowland wet-grasslands of Western Europe. Although we were already well aware of these problems by 1995, and farmland prescriptions have been used to try to arrest the declines since then, we have still lost nearly half of Britain’s breeding Lapwing in the last twenty years. Even on nature reserves and in sympathetically-managed wet-grassland, it has proved hard to boost the number of chicks produced. Why is this and what else is there that can be done?

bouThis is a summary of a presentation by Professor Jennifer Gill of the University of East Anglia and Dr Jen Smart of RSPB, delivered at the BOU’s Grassland Workshop (IOC Vancouver, 2018).

There are five key techniques in the tool-kit used by conservationists trying to support breeding waders:

  • Make the site attractive to waders
  • Manage predator numbers, particularly through lethal control
  • Manage habitat structure to make alternative prey available
  • Exclude predators, either permanently or temporarily
  • Invest in head-starting chicks, to boost productivity

Size of the problem

redshankThe decline in wader numbers in England has been happening for a very long time. In just the period 1995-2016, Lapwing numbers have fallen by a further 26% and Redshank numbers by 39%, according to Bird Trends, produced by BTO & JNCC. Within the English lowlands there has been a dramatic contraction into nature reserves, especially in the east of England.

The Breeding Waders in Wet Meadows survey showed that fields that are within nature reserves are much more likely to be occupied than other fields in wet grassland, particularly those that are included in wader-specific agri-environment schemes. The study is published in Ibis by Jen Smart et al.

smart 2014

Attracting breeding waders

Lowland wet grasslands in Broads

Creating shallow ditches. Mike Page/RSPB

Reserve managers and sympathetic landowners have become very good at creating the sort of habitats that attract breeding Lapwings. Autumn and winter grazing can be manipulated to produce short swards, whilst adding in shallow pools and foot-drains (linear features running through fields) increases feeding opportunities for chicks. See Restoration of wet features for breeding waders on lowland grassland 

The RSPB has invested heavily in time and equipment to deliver these lowland west grasslands, on their own land, on other nature reserves and on commercial farmland. By working with Natural England, they have helped to shape agri-environment schemes that can be used to deliver payments to farmers who are well-placed to create habitat that suits breeding waders.

Mark

wader pairsIn the east of England, there are now more than 3000 hectares of this attractive, well-managed wet grassland habitat, designed to be just right for species such as Lapwing. The graph alongside, drawn using RSPB data, shows the number of pairs of Lapwing (green), Redshank (red) and other waders (Oystercatcher, Avocet & Snipe: blue) in Berney Marshes RSPB reserve in eastern England for the period 1986 to 2016. There were early successes, as new areas were purchased and transformed, but growth in wader populations has not been sustained, despite ongoing improvements in land management. What is preventing further recovery?

Demographic processes

survivalIn a paper in the Journal of Ornithology, Maya Roodbergen et al  used demographic data collated across Europe to show that there had been long-term declines in nest survival and increases in nest predation rates in lowland wader species. One of the main focuses of management action at Berney Marshes is to maximise Lapwing productivity but nesting success is still below 0.6 chicks per pair in most years (see graph), which is the minimum estimated productivity for population stability (Macdonald & Bolton). Not enough chicks are being hatched, with the vast majority of egg losses being associated with fox activity.

Controlling foxes

The obvious solution for breeding waders must surely be to shoot foxes? It’s not that simple. In a multi-year, replicated experiment to assess the impact of controlling foxes and crows, RSPB scientists showed that there were no clear improvements in wader nesting success; effectiveness is very much site-specific. Much may well depend on how much fox control there is in the surrounding area.

foxIf fox impacts cannot be reduced sufficiently through lethal control, perhaps it is possible to reduce their effects on waders by understanding the ways in which foxes forage and to adapt the habitat appropriately? Work by Becky Laidlaw and others has shown that Lapwing nest predation rates are lower close to tall vegetation and in areas with complex wet features. However, Becky has also shown that management to create these features, even in areas of high wader density and effective predator mobbing, is only likely to achieve small reductions in nest predation. There is a WaderTales blog about this: Can habitat management rescue Lapwing populations?

Excluding foxes

malpasOne solution to the fox problem that does work is to exclude foxes (and badgers) from an area, by using electric fences. See paper by Lucy Malpas (now Lucy Mason). Fences may be deployed at different scales; just around individual nests, temporarily (around individual fields) or permanently (around larger areas).

  1. Nest-scale may be most appropriate for species such as Curlew, which have large territories and do not nest colonially. Finding nests is time consuming but relatively small lengths of fence could potentially be erected during the incubation period.
  2. Whole-site protection will suit semi-colonial species such as Lapwing. Although expensive to install, permanent fences can require relatively little maintenance and can potentially be powered by mains electricity. One disadvantage may be that the presence of large numbers of chicks can attract avian predators, such as birds of prey, which are themselves conservation priorities and hence difficult to manage.
  3. fence 2Field-scale fences usually rely on batteries, which need to be checked and changed, and fences need maintenance, as the grass grows and can short out the bottom strands. However, deployment at the field-level allows for dynamic use within a farming landscape and in accordance with agri-environment schemes. New research by RSPB and the University of East Anglia aims to see if fences need only to be deployed for relatively short periods. If pairs nest synchronously then groups of birds may be able to maintain the ‘fence-effect’ by mobbing predators, when a temporary fence is removed.

Head-starting

morgan 2018Although it might be possible to improve the habitat that is available for breeding waders and to reduce predation pressure, it is sometimes too late to boost numbers – simply because populations have shrunk to too low a level. At this point, head-starting (rearing chicks from eggs) may be appropriate. This blog celebrates the success of the first year of a joint initiative by RSPB and WWT (Project Godwit) to increase the local population of Black-tailed Godwits in the East Anglian fens: Head-starting Success.

In conclusion

In trying to boost breeding wader populations, land-managers and conservationists have developed techniques to increase site attractiveness and reduce predator impacts, through management, control and exclusion. The tools that are used will depend upon species, budget and conservation priorities.

This work was presented by Jennifer Gill & Jen Smart at a BOU symposium on the Conservation of Grassland Birds, in Vancouver, August 2018.

Blog adultWaderTales blogs about Lapwings and Redshanks

The work of RSPB and University of East Anglia scientists features strongly in these blogs, which focus on support for breeding wader populations in lowland wet grassland and on coastal saltings.


GFA in Iceland

WaderTales blogs are written by Graham Appleton (@grahamfappleton), who  has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland.  He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.

 

 

Scottish Wader Woes

The report on Scotland’s terrestrial bird species, covering the period 1994-2016, did not make easy reading for wader lovers. All but one species was contributing negatively to the upland bird indicator, with declines of over 40% for breeding Lapwing, Curlew, Dotterel, Oystercatcher and Golden Plover. In this short blog, there are links to information that helps to explain what might be going wrong for Scotland’s waders.

The figures from the report have been update in the Breeding Bird Survey for 2018 (published 2019) and these figures are now included below. Golden Plover is no longer part of the ‘over 40%’ club.

The full report is available on the SNH website (https://www.nature.scot/information-library-data-and-research/official-statistics/official-statistics-terrestrial-breeding-birds)

The updated Breeding Bird Survey results are available on the BTO website (https://www.bto.org/our-science/projects/bbs/latest-results)

One species has been increasing – Snipe up 22% *

snipe abundance change* BBS results for Snipe for 1995-2017 revise the change figure to show an increase of 32%.

The one spot of good news is that breeding Snipe numbers in Scotland have risen over the period 1994 to 2016. This is particularly encouraging, given declines in much of the rest of Britain and Ireland, as you can see in the map alongside and read in this WaderTales blog Snipe and Jack Snipe in the UK and Ireland.

In the map, produced for Bird Atlas 2007-11 (BTO, BirdWatch Ireland & SOC), pink colours show abundance increases and grey areas show decreases.

Lapwing declines largest – down 63% *

GHH picture* BBS results for Lapwing for 1995-2017 revise the change figure to show a decrease of 55%.

When a widespread species such as Lapwing is in decline this is bad news. Subtle difference in the way that lowland valleys are farmed may be part of the problem, as illustrated in this WaderTales blog, based on work by Mike Bell, written up with the help of John Calladine, of BTO Scotland: 25 years of wader declines.

Curlew down 62% *

Blog Jill P* BBS results for Curlew for 1995-2017 revise the change figure to show a decrease of 61%.

The Curlew is causing huge concerns in Ireland and Wales, where conservationists are contemplating its disappearance as a breeding species. Scotland holds much larger numbers but a decline of nearly two-thirds suggests that there are major problems here as well.

Two WaderTales blogs tell the Curlew story. Is the Curlew really near-threatened explains why we should be so worried about what is happening and Curlews can’t wait for a treatment plan summarises a BTO-led paper from Sam Franks and colleagues which attempts to explain the patterns we are seeing in the species’ decline.

Dotterel down 60%

IMG_2123

Alistair Baxter

Most of the information about Scotland’s breeding birds comes from annual data collected by volunteers contributing to the Breeding Bird Survey (BBS), organised by the BTO, in partnership with JNCC and RSPB. Dotterel is different; here the counts are dependent on dedicated surveys of Scotland’s high-mountain plateaus. Concern for the species is very much linked to climate change but this blog, based on a paper by the RSPB’s Daniel Hayhow and colleagues, shows that there may well be other reasons for the species decline: UK Dotterel numbers have fallen by 57%. The figure for the decline may be slightly out-of-date but the blog isn’t.

TGG OycOystercatcher down 44% *

* BBS results for Oystercatcher for 1995-2017 revise the change figure to show a decrease of 38%.

In England, the latest BBS report shows an increase of 49% in Oystercatcher numbers but, in Scotland, where there are far more breeding pairs, the species is in decline. Oystercatchers: from shingle beaches to roof-tops looks at the history of the species’ spread from the shoreline, into the hills and onto roofs and considers the role of predation in recent declines.

Golden Plover down 43% *

* BBS results for Golden Plover for 1995-2017 revise the change figure to show a decrease of 10%.

As noted in the press release about the SNH report ‘The golden plover population has declined by 43% since 1994 and stands at its lowest point since the BBS survey began. Declines may be linked to climate change, in part due to impacts on the abundance of craneflies during the breeding season”. There are two interesting papers about this by James Pearce-Higgins and colleagues.

golden ploverPearce-Higgins, J.W., Yalden, D.W. & Whittingham, M.J. 2005. Warmer springs advance the breeding phenology of golden plovers Pluvialis apricaria and their prey (Tipulidae). Oecologia 143: 470–476.

Pearce-Higgins, J.W., Dennis, P., Whittingham, M.J. & Yalden, D.W. 2010 Impacts of climate on prey abundance account for fluctuations in a population of a northern wader at the southern edge of its range. Global Change Biology 16: 12–23.

Common Sandpiper down 39% *

* BBS results for Common Sandpiper for 1995-2017 revise the change figure to show a decrease of 23%.

The Breeding Bird Survey does not properly capture trends for species found mostly along rivers. Data for Common Sandpiper are derived from the BTO Waterways Bird Survey and the Waterways Breeding Bird Survey.

Why no Redshank?

Unfortunately, breeding Redshank are now patchily distributed across Scotland, with too few being picked up by BBS surveyors to make a contribution to Scottish population indices. Across the UK, the latest published BBS decline is 38%. UK graphs for Oystercatcher, Redshank and Curlew are shown below.

UK BBS


GFA in Iceland

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton

 

Farming for waders in Iceland

Across the world, agriculture is one of the primary threats to biodiversity, as we tear up natural environments to create more space to feed an ever-growing and increasingly meat-hungry human population. Agricultural land can, however, also provide key resources for many species whose behaviours align with the rhythms of the farming year.

blog cows

In Iceland, farming areas support large and important populations of several wader species, including 75% of Europe’s Whimbrel and over half of Europe’s Dunlin. As the country welcomes more tourists and expands the range of crops grown for food and fuel, what might be the implications for iconic species such as Whimbrel, Dunlin and Black-tailed Godwit?

This paper by Lilja Jóhannesdóttir, of the University of Iceland, and colleagues there and at the universities of Aveiro (Portugal) and East Anglia (UK), investigates the use of farmland by waders living in a semi-natural landscape.

Paper details: Use of agricultural land by breeding waders in low intensity farming landscapes Lilja Jóhannesdóttir, José A. Alves, Jennifer A. Gill, & Tómas Grétar Gunnarsson Animal Conservation. doi:10.1111/acv.12390

A dynamic landscape

blog snipe postIn Iceland, volcanic activity poses serious short-term threats to agriculture, especially in areas close to the mid-Atlantic ridge, which runs through the island from south-west to north-east. Threats from volcanoes include ash-fall, lava, flooding of glacial rivers and earthquakes but, on the plus side, nutritional inputs from volcanoes have beneficial effects on soil fertility in these central areas. Over time, and with the assistance of wind and water, many of these nutrients collect in the lowlands of the country – the areas that now form the main agricultural areas, especially in the warmer south.

The distribution of breeding waders varies across lowland Iceland. A survey carried out between 2001 and 2003 showed that wader densities were greater in areas of the country that had been subject to higher rates of volcanic ash deposition with, for instance, three times as many waders in the south as in the west. See How volcanic eruptions help waders. As was shown in the paper at the heart of that blog, the nutrient signal associated with ash-fall breaks down in farmland. Here, perhaps as a consequence of the application of natural and artificial fertilisers over decades or even centuries, there is no association between ash-fall and wader density. Across the whole country, irrespective of the proximity of volcanoes, nutrient-rich agricultural land attracts waders – but which wader species and across which farmland habitats?

Waders and agriculture

In a previous paper, Lilja Jóhannesdóttir showed that over 90% of Icelandic farmers think it is important or very important to have rich birdlife on their estates, but that farmers also expect to increase the area of farmed land in the coming years. There’s more about this in the WaderTales blog: Do Iceland’s farmers care about wader conservation? It is important to understand the ways that waders currently use farmland, in the hope that nesting waders can continue to be accommodated within the future farming landscape of Iceland.

blog oyc bare

Perhaps Oystercatchers think that the fields have been ploughed especially for them?

Agriculture in Iceland is still relatively low in intensity and extent, and internationally important populations of several breeding bird species are abundant in farmed regions. Only about 2% of land is cultivated (about 7% of lowland areas), of which about 85% is hayfields (grass fields managed to produce crops of grass for storage as winter feed) and 15% consists of arable fields (mostly barley). This is similar to areas such as Norway, northern Canada and northern and western areas of the British Isles but contrasts sharply with the US and many countries in the EU which, on average, have 20% or more of their land under cultivation.

In these high-latitude landscapes, agricultural land can potentially provide resources that help to support wader species. To address these issues, Lilja conducted surveys of bird abundance on 64 farms in northern, western and southern areas of Iceland that vary in underlying soil productivity, and quantified:

  • Levels of breeding bird use of farmed land managed at three differing intensities, ranging from cultivated fields to semi-natural land
  • Changes in patterns of bird use of farmed land throughout the breeding season.

Farm survey

In Iceland, there are still large patches of natural or semi-natural habitats; they surround the hay-fields and arable fields that are at the heart of many farms. This arrangement creates gradients of agricultural intensity from the farm into the surrounding natural land, tapering from intensive management to moderate and light management.

BLOG gradient

The three intensity levels within Icelandic farmland can be roughly described as follows:

  • Intensive: Hayfields (85%) and arable fields (15%) fields. Most hayfields are mown twice per year and ploughed and reseeded every few years.
  • Moderate: Old hayfields that are rarely or never mown but are used for grazing, or fertilized grasslands used for livestock grazing.
  • Light: Semi-natural or natural areas under low intensity grazing, usually by sheep or horses, or with no agricultural influence, ranging from sparsely vegetated habitats to habitats with abundant vegetation (where grasses and bushes dominate the vegetation) and with a broad wetness gradient.

Fields corresponding to these three categories were surveyed on the 64 farms, firstly during the egg-laying and incubation period and then later, to coincided with chick rearing.

blog 3 habitats

Gradient of management from intensive (left) to wet semi-natural (right)

Where were the waders?

blog RK on postLarge numbers of waders were encountered in all transects in all parts of Iceland, with Black-tailed Godwit and Redshank contributing most records. There were also important numbers of Oystercatcher, Golden Plover, Dunlin, Snipe and Whimbrel. Overall, wader densities on farms did not vary significantly between regions or between early and late visits but there were some subtle differences:

  • Wader density varied significantly along the management gradient, with lower densities tending to occur in more intensively managed areas, particularly in the early (nest-laying and incubation) season.
  • Intensively managed fields in the west (where underlying soil productivity is lower) had higher densities of waders than in the north and south of the country.
  • There were seasonal declines in wader density on all three management types in the south, but seasonal increases on intensive and moderate management in the west and in fields under moderate management in the north.
  • There were some differences between species in these patterns (more details in paper).

blog redshank westOne of the interesting differences in the west was the redistribution of Redshank as the season progressed. There were three times as many pairs of Redshank in cultivated land during the chick-rearing period than during incubation, suggesting that adults may be moving broods into cultivated land. Resources for chicks may well be relatively more abundant or accessible in these areas, given the relatively low levels of nutrients in areas that are a long way from the active volcano belt. There’s also a suggestion that drainage ditches around cultivated fields in the west may provide important resources for Snipe.

What about the future?

blog distributions

Wader densities during the early (red) and later (blue) part of the breeding season (Modified from the paper in Journal of Animal Conservation)

Although the density of birds in Iceland’s agricultural landscapes tends to be higher in lightly managed than intensively managed agricultural land, densities in the areas under the most intense agricultural management are still high, suggesting that agricultural habitats provide important resources within these landscapes (see figure alongside). These density estimates (between 100 and 200 waders/km2) are typically much higher than those recorded in other countries in which these species breed.

Farmers in Iceland expect to expand their cultivated land in the coming years in response to increasing demand for agricultural production (Do Iceland’s farmers care about wader conservation?), and evidence from other countries throughout the world has shown how rapidly biodiversity can be lost in response to agricultural expansion and intensification. Protecting these landscapes from further development is crucial to the species that they support.

The authors suggest ways in which farming practises might change wader distributions in Iceland. Here are a few of the interesting points that they make:

  • When wader-rich semi-natural land is replaced by arable farming and intensively-managed hayfields, this is likely to reduce overall wader densities.
  • Losing wet features, which provide insect food for waders, may well have impacts for chick growth. Here’s a WaderTales blog that discusses the importance of wet features to Lapwings in the UK.
  • In other countries, early grass mowing is a direct threat to nests and chicks. Clutch and brood losses are already being observed in Iceland and, with warmer springs encouraging earlier grass growth, this could become more of a problem.
  • The conversion of less-intensively managed areas into farmland is likely to have most effect on Dunlin, Black-tailed Godwit and Whimbrel, which tend to occur in their highest densities in the least intensively managed lowland areas.

blog walk WhimbrelIt is estimated that between 4 and 5 million waders leave Iceland each autumn, for Europe, Africa and the South Pacific (Red-necked Phalarope). Iceland’s farmland supports many of these birds and this study highlights the need to protect them from the agricultural developments that have led to widespread wader losses throughout most of the world.

You can read the paper here

Use of agricultural land by breeding waders in low-intensity farming landscapes Lilja Jóhannesdóttir, José A. Alves, Jennifer A. Gill, & Tómas Grétar Gunnarsson. Animal Conservation. doi:10.1111/acv.12390

blog oycs & chick

 


 GFA in Iceland

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton

 

 

25 years of wader declines

This article summarises a Bird Study paper arising from a 25-year Scottish study of breeding Lapwing, Oystercatcher, Redshank & Curlew. The story is set against a backdrop of a changing farming landscape.

RC LapThe interesting and sobering feature of this paper about breeding waders by Mike Bell and John Calladine is that its focus is a ‘normal’ area of farmland in Scotland. If you’ve taken the A9 north of Stirling, through Strathallan, then you’ll have driven past the fields. Perhaps you might even have noticed displaying Lapwing, Oystercatcher, Curlew and Redshank? Over a 25-year period, the number of breeding waders in this valley and another one that runs northwest and that can be seen from the B827 has dropped from 600 pairs to just 76 – that’s a loss of 87%, or over 20 pairs per year.

So, what has changed in this part of Scotland that might be linked to these declines? The authors conclude that the reduction in numbers can be linked to changes in field management. Put simply, there are too few bare fields in the spring for Oystercatcher (down 95%) and Lapwing (down 88%). These two species hide their nests in ‘plain site’; they watch out for predators, take off early and hope that the eggs are coloured cryptically enough to avoid detection. Having left their nests, they attempt to deter and/or distract prowling crows etc.  Redshanks (down 87%) and Curlew (down 67%) have also declined, even though they hide their nests in long grass, about which more later.

map graph

Lapwing declines in the Strathallan area are not that much different to those that have been charted across much of Britain & Ireland

In for the long haul

In a survey in the late 1980s, this area of Strathallan held an important assemblage of farmland breeding waders, with particularly high densities of nesting Lapwing. Land use in the valley is predominantly agricultural, with a mixture of arable fields and grazing by sheep and beef cattle. It is a relatively open landscape with few hedgerows, some scattered shelter belts and small conifer plantations.

KS RedshankThis study started in 1990, when breeding densities of nesting Oystercatcher, Lapwing, Redshank and Curlew in the core area were still high, at 11.7, 35.6, 4.7 and 3.3 pairs/km2 respectively. Unlike a PhD project, which might include three years of data, Mike Bell has kept this survey going for 25 years. Mike is the volunteer Regional Representative for the British Trust for Ornithology’s Perthshire region.

Breeding waders within a core area of 65 fields and a small amount of wet fen were surveyed annually from 1990 to 2015. The field sizes were small, by modern standards, with only five fields larger than 20 ha. An additional 1 km2 of lowland mixed farmland was surveyed in most years, 4 km2 of moorland rough grazing was surveyed in four years and another 5.3 km2 of enclosed and unenclosed rough grazing and moorland was surveyed at the beginning and end of the survey period only.

Land management and usage were recorded for each field on the first visit in April or early May. Spring sward height in each field was recorded as one of three categories: no vegetation, short (<10 cm) or long (>10 cm). These sward categories comprised the following field types:

  • bare – ploughed or tilled land with no emergent vegetation
  • short – managed grass for grazing or mowing for hay or silage, rough grass, rush pasture, spring arable, setaside/fallow.
  • long – managed grass, rough grass, rush/pasture, setaside/fallow, heath/moorland, marsh/wetland, unmanaged rank grassland and woodland/scrub.

Where to find waders in Strathallan

In the early 1990s, Strathallan supported around 36 Lapwing pairs/km2 across the core study area, which is comparable with some of the highest densities reported anywhere in the UK. During the 25-year study, as the numbers of Lapwing, Oystercatcher, Redshank and Curlew declined, an increased proportion of the remaining breeding waders became restricted to areas with fields classed as ‘bare’ in spring, while the greatest losses were in fields with ‘short’ and ‘tall’ spring sward heights (see figure).

graphic

Changes in breeding densities of waders in Strathallan, on fields with different sward heights

Breeding densities of Curlew were low throughout the study area and, although overall numbers declined, there was low power to detect statistically significant changes. There were different patterns of change for Lapwing, Oystercatcher and Redshank within fields of different spring sward heights:

  • The least marked changes were in fields with no vegetation in spring.
  • Fields with short swards showed the largest declines.
  • The tallest spring sward heights supported the lowest densities of the three wader species, with Redshank present generally at low densities in all vegetation categories.
UK BBS

UK-wide Breeding Bird Survey trends for Oystercatcher, Redshank and Curlew. BBS is organised by BTO in partnership with JNCC and RSPB.

A changing farmland landscape

Sward heights reflected changing farming methods. Looking at the fields in terms of cropping regimes.

  • The highest densities of Oystercatcher were in spring-sown arable crops.
  • Rush pasture was the most favoured field type for Lapwing and Redshank at the start of the study but the amount of this habitat declined during the study, as farmers created semi-permanent pastures for over-wintering sheep. When this happened, birds became more restricted in their nesting distribution.
  • By 2015, very few fields were still under a crop rotation of grass and spring arable, that would have delivered a mosaic of sward structures. By this time, half of the Lapwing pairs were nesting in just four fields.

Breeding success

The breeding success of Lapwings was estimated in five sample fields that could easily be observed from roads or tracks without disturbing the adults. Lapwing productivity was less than 0.60 young fledged/pair (the bench-mark for a typical stable population) in all but three years and it was less than 0.25 young fledged/pair in 14 of the 22 years. With very low recruitment rates, it is not surprising that the Lapwing is in decline.

There are several WaderTales blogs about Lapwings breeding in lowland wet grassland, including A helping hand for Lapwings. A full list of WaderTales blogs can be found here.

What is changing?

TGG Oyc

The changing fortunes of Oystercatcher are discussed in this WaderTales blog

Within a mixed arable-pasture farmland environment, bare field and short swards in spring appear to be important to breeding waders. Losses of these preferred habitats type don’t appear to fully account for the decline in numbers, however.

Alongside changes to farmland habitats, other potential factors that could have contributed to the decline of the wader population in Strathallan include an increased incidence of poor spring weather, increased disturbance (including from dog-walkers in some fields in some years) and an increase in predators. Mike Bell thinks that one of the reasons for a possible link between productivity declines and wet weather is that birds are nesting in sub-optimal (long) grass and hence more affected by wetter conditions. He writes about this and potential reasons for increased disturbance in an upcoming article in Scottish Birds. A link to the Scottish Birds article will be included when available.

Densities of avian predators increased in Strathallan during the study period, with higher breeding densities of Carrion Crow and Buzzard and an increasing frequency of bigger flocks of non-breeding crows. There was no detectable change in breeding success during the study but it is possible that nest success was already depressed by predation when the study commenced.

A relentless decline

GHH pictureAlthough previously identified as a good area for breeding waders, in a Scottish context, there is nothing unique about this Strathallan study area. It is good to see these issues explored in Bird Study, the BTO journal. I am sure that the editor, Ian Hartley, will have been pleased to publish a paper based on a nice mix of dedicated fieldwork and scientific analysis – that’s what the BTO is all about.  If you want to understand the (not yet fully explained) sad demise of breeding waders in Scotland, check out the figures in the paper. These show a relentless, 25-year decline in nesting densities across a range of habitats and some less-than-subtle changes in the way that fields are now managed.

Here’s a link to the paper:

The decline of a population of farmland breeding waders: a twenty-five-year case study by Michael V. Bell & John Calladine in Bird Study, 64:2, 264-273 DOI: 10.1080/00063657.2017.1319903


 GFA in Iceland

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton