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.

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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).

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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

 

 

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Interpreting changing wader counts

Blog mixed flockWhen you count the number of Redshank on your local estuary and discover that there are fewer now than there were last year –  or five, or twenty years ago – what are the implications? Is this part of a national or international trend or has something changed within the estuary itself?

The first question to ask is, ‘what is happening elsewhere?’ and then to wonder about the ways in which numbers of birds in different sites might relate to each other. What actually happens to local counts when national counts go down – or go up, for that matter?

The UK Wetland Bird Survey (WeBS) data provide comprehensive and long-term monitoring of estuarine wader populations around our coastline. Thanks to volunteers who collect monthly counts each year, these data present an excellent opportunity to explore how bird distributions can change over time. A new paper by Verónica Méndez and colleagues from the University of East Anglia and British Trust for Ornithology uses counts of 19 species (18 waders plus Shelduck, an honorary wader) over a 26-year period to ask what happens to distribution and local abundance across our estuaries when overall population sizes go up or down.

Consequences of population change for local abundance and site occupancy of wintering waterbirds Verónica Méndez, Jennifer A. Gill, José A. Alves, Niall H. K. Burton & Richard G. Davies Diversity and Distributions. 2017;1–12. DOI: 10.1111/ddi.12653

The counters

Blog Counter 2A WeBS count can be a tough assignment for a volunteer birdwatcher. Being allocated to a stretch of an estuarine coastline and asked to visit it, whatever the weather, on a given weekend of every month, in every winter, is not the same as an invitation to go birdwatching in September to look for a Curlew Sandpiper.

The counts used in this paper are from the months of November through to February, when waders are largely settled for the winter and the weather can be less than clement. Many of the data-points for individual sites have been collected by the same person in all of the years analysed in the paper and every contribution is important.

WeBS70logo6a_smallWeBS is the successor of other, similar count schemes which are celebrating 70 years of continuous monitoring this year. It is organised by BTO, in partnership with RSPB and JNCC and in association with WWT. There are over 3000 registered WeBS volunteers, collecting data about the waterbirds that can be found on estuaries, in wetlands, on inland lakes, along river valleys and in local parks and villages.

Understanding change

Many populations of migratory birds are changing in number quite rapidly at present, but are these changes more likely to result in changes in occupancy (eg colonisation of or extinction from some sites) or changes in abundance within sites? Put simply, if extra waders arrive in the autumn, how do they distribute themselves across available sites? If fewer arrive, where will the gaps be found?

DN and BTG graphs

The contrasting fortunes of Dunlin and Black-tailed Godwit over the period covered in the new paper

Over the period studied in the paper (between 1980-85 and 2002-07), populations of five species declined, with the greatest losses occurring in Purple Sandpiper and Shelduck (both declined by about 25%), while there were increases for four, the biggest of which were Avocet (+1690%), Golden Plover (+554%) and Black-tailed Godwit (+418%). No birdwatcher will be shocked by the figures for Avocet or Black-tailed Godwit, wintering numbers of which have shot up, but Golden Plover is more of a surprise and may be linked to a move from inland fields to estuaries.

When the size of a wintering population of waders declined, Verónica Méndez and her colleagues found that the main consequence was a reduction in numbers across all sites. Birds were likely to stay on a site even if local numbers were dwindling. This suggests high levels of site-fidelity by individual waders, which is something we know from ringing and tracking studies. If you’re still alive then just do the same again – there could be a better site with a higher number of conspecifics somewhere else but it would be risky to try to find that out.

 

Blog Avocets

Thirty years ago, few people can have expected that they would ever see such a large flock of Avocets on the Humber

If the size of a wintering population increased, generally numbers went up within all occupied sites. The exceptions tended to occur in species for which original numbers were very small, such as for Greenshank, or species for which the change in numbers has been rapid – as seen in Avocet and Black-tailed Godwit.

If adults don’t change their wintering sites then increases are presumably being driven by juveniles. Their settlement decisions may be influenced by the distribution of adults of the same species, resulting in increased local abundance, rather than colonisation of new sites. For the two rapidly-expanding species, Black-tailed Godwit and Avocet, there was colonisation of 25 and 15 new sites, respectively, between 1980-85 and 2002-07, with some indication of more similar increases in sites that were closer together, which may reflect local movements among groups of nearby sites.

Designating sites

Blog Blackwit

Juvenile waders may well settle in areas where there are already populations of wintering adults

One of the key conservation measures for waders across Europe is the Special Protection Area (SPA) network, a collection of sites that are designated because they hold internationally or nationally important numbers of species, measured as a percentage of the population. Designated sites need to maintain numbers of all the species that hit this threshold percentage. However, if a national or European population gets larger (for example because of high breeding success) but the number on a particular site does not grow (or grows more slowly), then the species might drop below the threshold for protection, even if the site is unchanged. Theoretically this could affect a site’s protected status for that species, although is unlikely to be a problem, as most sites are designated for many species.

This new paper shows that gains and losses tend to be fairly constant across all sites, making it unlikely that a site designation would be affected by national or European-scale changes. In only one species (Ringed Plover), have numbers declined so much in some sites that the total number of sites exceeding the threshold for that species has decreased.

Keep counting!

Blog Counter 1Habitat availability and site fidelity, along with species longevity, may explain the strong tendency for local population abundance to change much more than site occupancy, in our wintering waders. Given the statutory importance of maintaining waterbird populations in designated protected areas, it is important to continue local and national surveys that can identify changes in local abundance and relate these to large-scale processes.

Returning to the earlier question – When you count the number of Redshank on your local estuary and discover that there are fewer now than there were last year –  or five, or twenty years ago – what are the implications?

This new paper shows that it is unlikely that a local drop in a species’ numbers is caused by a redistribution of birds. Factors that might lie behind a local decline need to be investigated locally, if the trend is not replicated elsewhere. The authors could only reach this conclusion because they had 26 years of WeBS data from a range of sites at their disposal. Future generations of WeBS counters will hopefully continue to monitor the conditions of our estuaries, working together throughout the country to interpret local counts within a national framework.

Paper

Consequences of population change for local abundance and site occupancy of wintering waterbirds Verónica Méndez, Jennifer A. Gill, José A. Alves, Niall H. K. Burton & Richard G. Davies Diversity and Distributions. 2017;1–12. DOI: 10.1111/ddi.12653

Blog RINGOS


 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

 

 

Wales: a special place for waders

From winter beaches to summer moorland and woodland, Wales provides essential habitats for waders. 

welsh-header

There are over forty WaderTales blogs so far. Here’s a selection of ten that may well appeal to birdwatchers in Wales.

Winter beaches & estuaries

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Most Oystercatchers are being ringed with two letter engraved rings, along with two colour-rings: Photo Tómas Gunnarsson

Wales holds important populations of waders in the wintertime – everything from Bar-tailed Godwits from Siberia to Turnstones from Canada. Some of the Oystercatchers seen in sites such as the Burry Inlet or the Menai Strait are from Iceland, where they can be found alongside Redshanks and Golden Plover that have also arrived from the north. They emphasise the close links between Wales and Iceland when it come to birdlife.  Migratory decisions for Icelandic Oystercatchers explains how a new project is examining the costs and benefits of being a migrant. Welsh reports of Icelandic colour-ringed birds are helping to provide answers.

snipe-1Interestingly, while there are similar links between Ireland and Iceland, the migratory provenance of Welsh Snipe may be very different to that of Irish ones. A quarter of foreign-ringed Snipe reported in Ireland have been found to be wearing Icelandic rings but, so far, no Reykjavik-ringed Snipe have been spotted in Wales. Snipe & Jack Snipe in the UK and Ireland compares the migratory strategies of the two species and laments the decline of Common Snipe, as a breeding species.

Protecting key wintering sites is a high priority when it comes to wader conservation. A recent BTO and WWT project aims to provide better information as to how species as diverse as Dunlin and Shelduck make use of the Severn Estuary. This is important work, with major relevance to discussions as to how power might be generated within the estuary. Tracking waders on the Severn urges birdwatchers to look for colour-marked birds. Initial results, shared at the recent International Wader Study Group conference, indicate that the home range of a Redshank is ten times as big as originally thought. It will be interesting to see what else this study reveals.

horse-and-flockHundreds of Welsh birdwatchers take part in the Wetland Bird Survey and the intensive work involved in periodic Low Tide Counts. These identify and monitor key sites and establish the most important feeding sites within estuaries. Whilst mud  and sand-flats are, of course, important to waders, so are roost sites. A place to roost discusses the importance of safe, high-tide roosts, especially in terms of energetics. I had not realised that it has been estimated that the cost of flying to and from roosts might account for up to 14% of a bird’s daily energy expenditure. That’s something to think about next time you see a dog chasing off a flock of roosting waders.

Passing through

whimbrel-mig-fig1There is exciting work going on in Wales to understand why so many Whimbrel spend time in the country in the spring. Whimbrels on the move summarises a recent paper about the movements of Icelandic, ringed Whimbrel. Since its publication, a new paper has shown that Whimbrel are able to fly between Iceland and west Africa in one jump but that they sometimes need to stop off on the way north. See Very rapid long-distance sea crossing by a migratory bird by José Alves and colleagues.

Breeding Waders

Wales provides homes to many breeding waders, from Ringed Plover on the coast, via Little Ringed Plover and Commons Sandpiper along rivers and into the moorland for Curlew and Dunlin, passing a forest with Woodcock en route. And that’s only giving a mention to half of the country’s breeding wader species.

CattleStarting on salt-marsh, Big-foot and the Redshank nest investigates appropriate cattle stocking levels for successful Redshank breeding. Although the work was undertaken in northwest England, there is no reason to believe that Welsh cattle area any less careful as to where they put their feet. There are several other blogs about Lapwings and Redshank on the WaderTales site.

We are all aware of the issues facing upland waders. The next blog was written to promote a survey in England, looking at the distribution of waders along the moorland/farmland interface, but the stories will have resonance with Welsh birdwatchers. All downhill for upland waders outlines changes to breeding numbers and distributions of waders breeding in England’s uplands.

Curlew e (2)

Curlews fly vast distances to spend the winter on the estuaries of Britain & Ireland (© Graham Catley)

Is the Curlew really near-threatened? considers the plight of breeding Curlew. It’s easy to understand why RSPB, BTO, GWCT and BirdWatch Ireland are focusing on this species How long will it be until breeding Curlew are lost from Wales, completely?

Predation is acknowledged as a major issue for Curlew but is this going to be a problem for Oystercatchers too? Oystercatchers: from shingle beach to roof-tops reveals a significant decline of the species in Scotland, mediated to some extent by range expansion in three dimensions. There’s a specific mention of the Burry Inlet control programme of the 1970s.

The strangest Welsh wader has to be the Woodcock – probing about in winter fields and nesting in forestry plantations. Conserving British-breeding Woodcock focuses on worrying results from the latest GWCT/BTO survey and work to reduce losses during the shooting season.

Further reading

Hopefully, this summary  gives a flavour of some of the issues being faced by Welsh waders and the research to which they are contributing. There are already over 40 blogs in the WaderTales series, with one or two new blogs being produced each month. If you want to know more about wader migration or moult, how volcanoes affect breeding waders in Iceland, why Black-tailed Godwits wear colour-rings or if there are costs to carrying a geolocator have a look here.


GFA in IcelandGraham (@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.

Can habitat management rescue Lapwing populations?

Can a mosaic of habitats boost hatching success in grassland-breeding Lapwings?

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Lapwings are becoming more and more restricted in their distribution within the United Kingdom, with an increasing proportion dependent on a small number of lowland wet grassland sites, particularly nature reserves. Working in this habitat, a team from the RSPB and the University of East Anglia has been trying to work out if it is possible to substantially improve Lapwing productivity without using intensive, costly predator management, in the form of permanent electric fences.

Background

graphThe RSPB has been monitoring breeding waders on their Berney Marshes reserve in Norfolk for over 20 years. Even with fox control, a wader-friendly grazing regime and sensitive regulation of water levels, Lapwing nesting success on this site is still below 0.6-0.8 chicks per pairs in most years, which is the estimated range required for population stability (Macdonald & Bolton 2008a). Predation is the main issue that is still limiting productivity.

Previous work has shown that:

  • Providing areas of tall, dense grass (often along field verges) can encourage populations of small mammals, which are the main prey of most wader nest predators (Laidlaw et al 2012).
  • The lay-out of wet features can influence Lapwing nesting densities (Eglington et al 2008).
  • Nest survival is higher when Lapwing densities are higher (Macdonald & Bolton 2008b).

The team believe that these three factors – small mammal distribution, surface water and Lapwing nesting density – are very likely to influence the behaviour and distribution of red foxes, the key predator in this study area.

There is more background information in the WaderTales blog entitled A Helping Hand for Lapwings and in a perspectives article in Wader Study by Jen Smart.

ditchIn a recent RSPB/UEA project, Dr Becky Laidlaw has investigated these relationships further and has then used the trends that have been established to model different potential management scenarios. What could happen if nesting densities, wetness and the proximity of verges with small mammals could all be varied in the best ways possible? Is there a theoretical scenario in which productivity is high enough to fuel population growth?

The paper is published as: Scenarios of habitat management options to reduce predator impacts on nesting waders. Rebecca A. Laidlaw, Jennifer Smart, Mark A. Smart and Jennifer A. Gill 2016 Journal of Applied Ecology doi: 10.1111/1365-2664.12838

The right habitat mix?

Using relationships established from previous studies and collating seven years of information on over 1400 individual nesting attempts, Dr Becky Laidlaw and her colleagues from UEA and RSPB saw that, not only was nesting success being influenced by wetness and the proximity of tall grass, there were some subtleties relating to the way that habitats are distributed. Might it be possible to  redesign the site so as to create a patchwork that could achieve the required productivity levels? Becky had two variables to play with – verges and wet features.

Verges influence predation rates, with Lapwing nests further from tall vegetation areas having a higher likelihood of being predated. This makes sense if foxes are concentrating on catching small mammals in areas with high mammal densities, and are more likely to ignore eggs that are laid in short grass close to mammal-rich verges.

proper-wet

There are plenty of wet features at Berney. The River Yare is in the foreground.

Water also influences wader nest predation rates. This is not surprising; if you are a fox, it is probably going to be harder to search for nests in a wet field with lots of pools and ditches than in a dry field. Interestingly, the study found that nests in the centre of dry fields were more at risk than those at the centre of wet fields. In a wet field, it’s riskier to nest along the edge, whilst in a dry field the risk increases the further the nest is from the edge.

wet-v-dry-graph

Part of a figure in Scenarios of habitat management options to reduce predator impacts, published in Journal of Applied Ecology by Laidlaw et al (Journal of Applied Ecology, 2016)

chicks

The team want to see more Lapwing chicks. These are newly-hatched.

The study confirmed that isolated Lapwing nests are more at risk of predation, potentially because single pairs don’t benefit from the mobbing defensive behaviour provided by having plenty of nesting neighbours. They found a similar pattern with Redshank nest predation risk; these scarcer breeding waders appear to be protected by the presence of more Lapwing.

Scenario modelling

Becky then worked with Mark Smart, the RSPB manager with responsibility for Berney Marshes, to model some potential future management scenarios for the site. They worked out where it would be feasible to add or remove verges and increase or decrease surface wetness within fields. Becky then used existing relationships to predict what changes in nest predation rates might be expected. Were there management options that could significantly increase survival rates of nests?

ralphBecky compared the different modelled management scenarios with the long term average nest predation rate for the site. She found a significant (roughly 20%) reduction in nest predation could potentially be achieved with the addition of tall vegetation, but only for nests close to field edges in areas of high Lapwing nest density. Importantly, this sort of decrease in nest predation levels could potentially increase the number of chicks hatching by around 100 each year, but such management relies upon areas of sufficiently high Lapwing breeding density being available.

The influence of nesting density

The aim of this applied research was to find a way to manage breeding habitat for Lapwing that could be rolled out to areas of conservation-sensitive farming outside nature reserves. Given the subtleties of creating the right patchwork of wet features and long grass at Berney, it’s going to be tricky to get similar benefits on other sites. If habitat management alone is not enough, even when used alongside fox control, then what else can be done?

Becky has a possible answer. “The breeding density measure we are using is the number of active nests within 100 metres of a nest. It may therefore be important not only for nests to be clustered in fields with appropriate conditions, but also that they are at the same stage at the same time. Synchronous nesting is something that we think might be very important.”

fenceFrom data collected on RSPB reserves with and without electric fences (which exclude foxes), it is clear that fencing greatly increases the synchrony of nesting attempts (because most of the early nesting attempts are successful). Given that the density of active nests has a major effect on nest survival rates, increasing the number of nests active at the same time may well provide a greater level of protection, through the mobbing behaviour of Lapwing, and therefore lead to greater hatching success.

As part of a new piece of research (funded by NERC, a UK government research council), Becky and the UEA/RSPB team are going to test whether the provision of temporary electric fences for just the early part of the breeding season can provide sufficient protection to increase hatching success, as a consequence of nests being more synchronous. If early-reared chicks are more likely to fledge than late-reared chicks, there also may be additional knock-on benefits post-hatching and through to the recruitment stage.

Becky is hopeful. “We understand how wader predation rates are influenced by the proximity to verges, the accessibility issues caused by water and the mobbing, defensive behaviour of waders. We are now interested in determining the best way to use this information in management. With the new work with fences we’re going to be specifically exploring the importance of synchrony to both nest success and productivity”.

Scenarios of habitat management options to reduce predator impacts on nesting waders. Rebecca A. Laidlaw, Jennifer Smart, Mark A. Smart and Jennifer A. Gill 2016 Journal of Applied Ecology doi: 10.1111/1365-2664.12838

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GFA in IcelandGraham (@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.

 

Big Foot and the Redshank Nest

What’s the crunch point? Grazed saltmarsh is an important habitat for Redshank but the addition of an extra four large feet can have serious negative effects. 

Cattle top adam cross

Each grazing unit comes with four very large feet (Adam Cross)

In a 2016 paper in Agriculture, Ecosystems & Environment, Elwyn Sharps and colleagues from Bangor University, CEH and the RSPB have shown that there is a tricky balance between providing the open, grazed habitats in which Redshanks can breed and minimising the likelihood of nests being trampled by cattle. If only cattle could do their important habitat management work outside the nesting season? However, the grass keeps growing and these four-footed, saltmarsh mowing machines usually arrive on site in spring and stay throughout the summer.

Sharps, E., Garbutt, A., Hiddink, J. G., Smart, J., & Skov, M. W. (2016). Light grazing of saltmarshes increases the availability of nest sites for Common Redshank Tringa totanus, but reduces their quality. Agriculture, Ecosystems & Environment, 221, 71-78. 

Background

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Distribution map from Bird Atlas 2007-11, which is a joint project between BTO, BirdWatch ireland and the Scottish Ornithologists’ Club

In the United Kingdom, Redshanks are amber listed species of conservation concern, increasingly restricted in their distribution. The map alongside shows that breeding Redshanks have been lost from many areas (downwards pointing black arrows). More distribution maps from Bird Atlas 2007-11 can be found on the BTO Mapstore.

Although they breed in various grassland habitats, coastal saltmarshes are internationally important. The breeding population on British saltmarshes has reduced by over 50% since 1985. Declines have been linked to grazing management, as breeding densities are higher with light and moderate grazing than on heavily grazed or ungrazed saltmarshes (Norris et al., 1998; Malpas et al., 2013).

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, which 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 his colleagues, working on the saltmarshes of the Ribble Estuary in northwest England, were interested to see just how light a grazing regime worked for the local Redshanks.

CattleWorking on the Wash, nearly twenty years previously, Ken Norris and colleagues had found that breeding densities were higher in structurally diverse grazed vegetation, and recommend low stocking densities of about 1 cattle ha-1, in order to create a patchy vegetation sward, suitable for nesting Redshank. This falls within the UK Environment Agency definition of light saltmarsh cattle grazing of between 0.7 and 1 young cattle per hectare between April and October, which translates to an annual cattle density of 0.3 to 0.5 cattle per hectare per year.  Work on the Ribble suggests that light grazing can reduce nest survival both directly through nest trampling and indirectly through accelerating predation risks. Breeding densities may appear high in some areas but productivity can still be very low.

An earlier paper by Elwyn Sharps et al. showed that the risk of Redshank nest predation increased from 28% with no grazing to 95% with grazing of 0.5 cattle per hectare per year, which is still within the definition of light grazing. Some of the nest failures were due to trampling, with 1 out of 5 nests being affected in areas with the lowest stocking rates and 4 out of 8 in the most heavily stocked (though still defined as lightly-grazed) area.

What do Redshank need?

Trampled egg christine tansey

Crunch point: when a large foot meets a fragile clutch (Christine Tansey)

In lowland wet grasslands, Jennifer Smart demonstrated that Redshank select tall nest vegetation, with some additional cover in a wider 10m area around the nest. Elwyn Sharps investigated nest site selection by Redshank breeding in six lightly grazed saltmarshes around the Ribble in with cattle densities were between of 0 to 0.55 grazing units ha-1 y-1.  In May and June 2012, a total of 45 Redshank nests were found across the six saltmarshes (between 5 and 10 nests per marsh) and vegetation heights and species composition were measured at and in the vicinity of nests, as well as at control points.

Redshank nest christine tansey

Christine Tansey

On The Ribble, vegetation height was taller at, next to and in the wider area around nests, when compared to control points, for all spatial scales studied, in line with those found on lowland wet grasslands. The vegetation composition was different in the immediate vicinity and in the wider area around nests than at control points, indicating that Redshank select nest sites surrounded by particular species of vegetation. Most of the dissimilarity between nests and control points was due to red fescue (Festuca rubra), which was more abundant near nests than at control points. There is a suggestion from the Ribble data that Redshank select nests within communities of F. rubra, which is a species associated with cattle-grazing in higher elevation saltmarsh.

Implications for land management

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Not quite long enough? Redshank nests are often completely hidden withing clumps of grass (Kevin Simmonds)

The results of this study suggest that livestock grazing plays an important role in creating the F. rubra nesting habitat preferred by Redshank nesting on the Ribble Estuary. However, even low intensity conservation grazing can create a shorter than ideal sward height, potentially leaving Redshank nests more vulnerable to predators. Translating the UK Environment Agency light grazing guidelines of 0.7-1 young cattle per hectare between April and October to measurements used in this study would mean an annual cattle density of around 0.4-0.5 cattle per hectare per year, which this study suggests is too intensive for breeding Redshank.

Elwyn Sharps suggests that future solutions should focus on designing grazing regimes which increases sward heights for Redshank nesting. This could include delaying the start of grazing until most Redshank stop nesting in mid-July, but then grazing more intensively afterwards. This would allow vegetation to remain tall during the nesting season, but would still maintain a cover of F. rubra.

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To read more about RSPB studies of breeding Redshanks visit this WaderTales blog (Kirsty Turner)

Another potential management solution may be a rotational grazing system, whereby saltmarshes are grazed and left ungrazed in alternate years, potentially improving habitat quality by allowing the vegetation to grow taller in the ungrazed year. However, on a small scale, Redshank may then select the part of a saltmarsh that was previously ungrazed , and therefore the area that will soon be grazed. It is clear that there are a number of possible solutions to this problem that require further investigations if the ideal saltmarsh management option for Redshank is to be ascertained. In working out how to manage saltmarshes for breeding waders, land managers will need to take account of the needs of other breeding species, overwintering wildfowl, and wider saltmarsh biodiversity, each of which may apply different constraints.

Sharps, E., Garbutt, A., Hiddink, J. G., Smart, J., & Skov, M. W. (2016). Light grazing of saltmarshes increases the availability of nest sites for Common Redshank Tringa totanus, but reduces their quality. Agriculture, Ecosystems & Environment, 221, 71-78.

And another problem…

In a more recent 2017 paper in Ecology & Evolution, Elwyn Sharps and colleagues show that cattle spend their time in the same areas of a 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”.

Nest trampling and ground nesting birds: Quantifying temporal and spatial overlap between cattle activity and breeding redshank.


 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

 

 

All downhill for upland waders?

 

Are targeted payments for England’s upland farmers benefiting Curlew, Lapwing, Oystercatcher, Redshank and Snipe?

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The farmed land that fringes our moors provides important habitats for breeding waders (Dawn Balmer)

In the period 1995 to 2013, England lost 32% of its breeding Curlew, 31% of its Redshank, 27% of its Lapwing and 14% of its Snipe, according to the latest Breeding Bird Survey results. The uplands are the main stronghold for Curlew and hold (or used to hold?) significant numbers of the other three declining species. Is the story one of total gloom or are there areas where sensitive farm management and agri-environment payments are successfully supporting waders and other species associated with upland farms? A new survey, funded by Defra and coordinated by BTO aims to find some answers.

The snappily-titled Breeding Waders of English Upland Farmland survey starts in April and volunteers are still needed in many areas. Please visit the BTO website if you may be able to help.

More about the key species:

curle 004 (nest) (Derek Belsey) (A)

Derek Belsey

Curlew (recent 32% decline in England). The species is globally defined as near-threatened and has been added to the red list of conservation concern in the UK. Losses have been particularly severe in Ireland, Northern Ireland and Wales but the distribution is shrinking in England. There’s a WaderTales blog about Curlew here. Is the Curlew really ‘near-threatened’?

Lapwing (recent 27% decline in England). Most of the work to try to understand recent declines in Lapwing numbers has been undertaken on lowland wet grassland, where cooperative mobbing of predators is an important part of the daily routine for parents. In the uplands, where breeding densities are lower, it would not be surprising if predation pressures could be impeding species recovery. There are two WaderTales blogs about these issues. A helping hand for Lapwings and How well do Lapwings and Redshanks grow?

redsh 058 e (Jill Pakenham) (A)

Jill Pakenham

Redshank (recent 31% decline in England). The situation for Redshank is very similar to that for Lapwing, the presence of which may help in predator defence. There is a WaderTales blog about the special issues in the Uists (NW Scotland), where introduced hedgehogs are causing huge problems in this key wader hot-spot. Prickly problems for breeding waders

Snipe (recent 14% decline in England). The survey methods used in the new BWEUF survey are not designed to detect Snipe, which are mostly active at dusk, but the visits should provide useful count and distribution data for an under-researched species.

oyste 066 e (Nigel Clark) (A)

Nigel Clark

Oystercatcher (recent increase of 56% in England). Much of the increase may well be occurring in river valleys and newly created wetlands and gravel pits, rather than in the uplands. We know from the recent Moorland Forum report Understanding Predation that there have been changes in Oystercatcher abundance in much of upland Scotland between 1990 and 2010, potentially linked to predation pressure. It would not be surprising if similar processes operate in the English uplands.

How the BWEUF survey will work

Breeding wader populations in the UK have been a major conservation priority for some years. Declines continue despite the implementation of conservation measures that are designed to deliver appropriate habitats, some of which are supported through agri-environment schemes (AES). While enhanced monitoring of many upland and lowland habitats would be valuable, a particular gap is evident for in-bye farmland. This habitat can be defined as juncus/rush pastures, semi-improved pastures and meadows below the moorland line, although it technically includes all enclosed farmland. Using Defra funding, Natural England has commissioned BTO to run a volunteer-based survey, with RSPB field-staff filling gaps in less accessible areas.

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Photo: Dawn Balmer

This project will assess the importance of in-bye land for waders, by estimating the total numbers present in these habitats, relative to national estimates measured from Bird Atlas 2007-11 data. More importantly, it will set a baseline against which to measure future change in breeding numbers.  This will be used to assess the success of Environmental Stewardship management, as well as to measure differences in numbers between AES and non-scheme habitats for waders that nest and/or forage on in-bye farmland. The survey will use 2×2km grid squares (tetrads), as in Bird Atlas 2007-11. Volunteers are asked to make two morning visits to each tetrad, one between early April and mid-May and a second before mid-July, with a minimum of a two-week gap between visits. On each visit, volunteers will be asked to survey as many as possible of the fields in this in-bye buffer of 1km below the moorland line. They will walk to within 100m of every part of each field to which they have access, recording all birds seen and heard, noting any display or territorial behaviour and mapping the locations of target wader species.

yelwa 015 e (Jill Pakenham) (A) (2)

There’s an opportunity to record other species of conservation concer, such as this red-listed Yellow Wagtail (Jill Pakenham)

The key features of grassland management and structure, along with other land use, which dictate suitability for waders, will be recorded.  Predation has been identified as one potential driver of population decline – or an impediment to species recovery – so observers will be asked to record avian and non-avian predators.

Birdwatchers do not normally spend much time in this in-bye habitat so here’s an opportunity to capture as much information as possible, especially for any other waders and gamebirds (Black Grouse, Grey Partridge, Pheasant, and Red-legged Partridge). Valuable information can be data can be collected for Cuckoo, Linnet, Meadow Pipit, Reed Bunting, Ring Ouzel, Skylark, Stonechat, Twite, Wheatear, Whinchat and Yellow Wagtail, many of which are red-listed species of conservation concern (and bonus birds on a day’s birdwatching). To view further information on survey methodology follow this link.

In Summary

The wader declines quoted in this article use Breeding Bird Survey data from 1995 but there is evidence of longer-term falls for Curlew (55% since 1975), Lapwing (65%), Redshank (65%) and Snipe (90%). These are worrying numbers and it is to be hoped that the BTO can find enough volunteers for BWEUF, despite the fact that many of the survey squares are a long way from the flat-lands in which most English birdwatchers live. Curlews, Lapwings, Oystercatchers, Redshanks and Snipe are counting on us to count them.


 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

Tracking waders on the Severn

Birdwatchers are being asked to help with some cutting-edge science, simply by reporting sightings of colour-dyed Dunlin and colour-ringed Curlew and Redshank.

Severn 1 WWT (2)

The Severn: an empty estuary or a food-rich haven? (Corinna Blake)

The tides that create unique feeding opportunities for waders and other waterbirds on the Severn can potentially be harnessed to produce large amounts of clean energy. New impact assessment work aims to see how a development that would bring big benefits to the local economy might be carried out with as little negative environmental side-effects as possible.

Colour ringed Curlew by Kane Brides

Birdwatchers are asked to look out for colour-ringed Curlew and Redshank (Kane Brides)

The Severn is a great place for birds, especially waders, attracted to the area by mud that has high densities of mud-loving invertebrates such as ragworms. It is designated as an SPA, because of its importance to wintering species such as Bewick’s Swan, Curlew, Dunlin, Pintail, Redshank and Shelduck, and the spring passage of Ringed Plovers. There’s more about the SPA on the JNCC’s website.

The British Trust for Ornithology and Wildfowl & Wetlands Trust scientists have been awarded a contract to undertake an Environmental Impact Assessment for the proposed Cardiff Tidal Lagoon  by Tidal Lagoon Power, with BTO focusing on waders and WWT on ducks. It’s a unique opportunity not only to inform conservation planning but also to answer questions about the winter ecology of some key species. The team aims to:

  • Validate and refine methods developed by Richard Stillman (Bournemouth University) that predict bird distributions from food availability. (It’s easier to map food distribution than to follow bird movements)
  • Understand patterns of movement of species that use the proposed development area and other key sites, such as the Gwent Levels.
  • Track birds in order to identify feeding and roosting areas that are used when birds are hard to observe – in poor weather, at night and at all stages of tide.
  • Work out how mobile birds are, in order to propose ways in which lost feeding opportunities might be replicated as close by as possible.

Tagging

Tag on Curlew back (head covered to keep bird calm) by Lucy Wright

Tags like this should reveal how waders and ducks use the Severn estuary. Curlew by Lucy Wright.

Tagging is an important part of the project. Four-gramme Pathtrack tags are being glued to the backs of a sample of Curlew, Redshank, Shelduck and (hopefully) Shoveler. These should stay on for a couple of months, during which time movements will be logged every 90 minutes and downloaded using UHF receiving stations set up around the Severn. These four species have been chosen because, for each, more than 10% of the estuary’s population lies within the proposed footprint of the tidal lagoon.

Colour-rings

Colour ringed Redshank by Emily Scragg

This colour-ringed Redshank may well breed in Iceland but which areas of mud-flat does it use in the winter? (Emily Scragg)

Tagged Redshank and Curlew are also being colour-ringed, alongside others that are not being tagged. By collecting reports of colour-ringed birds from birdwatchers, the BTO team will be able to monitor the efficacy of the tag down-load process and keep a track of movements when the tags stop transmitting. As an added bonus, the colour-rings may generate some new information about the breeding sites of waders that winter on the Severn.

Sightings of colour-ringed birds would be very much appreciated. Five rings have been used on both Redshank and Curlew. Please submit sightings (date time and ideally a six-figure grid reference) to Emily.scragg@bto.org who would also be interested in “ratio counts” of flocks of birds – simply the number of colour-rings and the size of the flock.

Colour-dyed Dunlin

The Severn Estuary holds an estimated 3.2% of the European wintering population of the alpina race of Dunlin, birds that breed from Siberia across to northern Scandinavia. Dunlin are too small to carry transmitters that can be used with base stations so the team has gone back to traditional picric dye in order to look at the mobility of flocks. Any sightings of colour-marked Dunlin will be appreciated by emily.scragg@bto.org. Where possible, please submit ratio counts broken up into yellow/orange on breast (adults), yellow/orange on the rump (juveniles) and unmarked birds, together with date, time and location (ideally with six-figure reference).

Colour-dyed Shelduck

shelduck Kane Brides

The neck of this tagged Shelduck will be dyed yellow before release (Kane Brides)

It’s not just waders.  Over 3,000 Shelduck winter on the Severn, which is more than 1% of the European population. A sample has been caught by WWT. Ringed birds have a yellow/orange dye mark on the normally white plumage on the neck/upper breast (between the dark green head and the brown breast band). No Shoveler have been caught yet but the aim will be to put a similar dye-mark on these birds too.  Sightings of dye-marked ducks should be reported to Ed.burrell@wwt.org.uk

Impact Assessment

The consortium of organisations that is working on this new tidal-power study is well placed to combine impact assessment with high quality wader science. By focusing on Curlew and Redshank, both red-listed species of conservation concerned, it is to be hoped that more will be learnt about the winter feeding ecology of these two species. The BTO team has already discovered that Redshank fly further at night than was previously thought and hope to get to understand some of the pressures facing Curlew, now classified as globally near-threatened (see separate WaderTales blog)

Severn 4 WWT

The Severn – Gareth Bradbury/WWT

This is not the first impact assessment work that has managed to incorporate research that increases the scientific understanding of wader behaviour and ecology. Two other examples are given below:

The Wash: Back in the 1970s, a plan to build huge reservoirs on the mud flats of the Wash, in which to store fresh water that might meet the growing demands of southeast England, led to a doubling of wader catching activity, intensive studies of their feeding ecology and complementary work on other taxa. Much was learned about the mobility of species within this huge estuary and the turn-over of birds within the annual cycle. A draft copy of the report is available on line at the NERC website 

Cardiff Bay: In the period 1989 to 2003, long-term studies took place to try to understand the impacts of closing Cardiff Bay and hence reducing the amount of tidal feeding area for waders. Following the development, it was shown that Redshank that had been displaced from the Bay were in poorer condition and had lower survival rates in subsequent winters.  There’s a summary on the JNCC website. The papers listed at the bottom of this JNCC web-page are essential reading for anyone trying to counter the ‘birds will simply go elsewhere’ arguments, which are sometimes put forward in favour of development work.


 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

How well do Lapwings and Redshanks grow?

There has been an assumption that managers of nature reserves know how to provide the right foraging conditions for Lapwing and Redshank chicks.  This paper in Wader Study shows that they do.

Lapwing chick Andy Hay rspb-images (2)

How quickly will this Lapwing chick grow? Photo: Andy Hay/RSPB images

For conservationists looking to increase wader populations, attracting birds to a chosen site is a good first step, but only if pairs can breed more successfully than they would have done elsewhere.  To understand whether a species recovery prescription works or, if it does not, to understand what is going wrong, it’s necessary to measure nest success, chick growth and fledging rates.  In their paper in the journal Wader Study, Lucy Mason and Jen Smart focus on the middle of these – how well chicks grow – to check whether the right feeding conditions are being provided.

Mason, L.R. and Smart, J. Wader chick condition is not limited by resource availability on wader-friendly lowland wet grassland sites in the UK. Wader Study 122:3 Dec 2015

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Tags make it easier to find ringed Redshanks. Photo: Kirsty Turner

Breeding success for Lapwing and Redshank can be poor, even on protected sites, which often leads site managers and policymakers to ask whether low food availability might be limiting chick survival, despite management aimed at providing optimum foraging conditions. Although this question is difficult to answer on a large scale, Lucy and her team were able to monitor and compare wader chick body condition and rates of growth across a range of UK sites.  If food availability is an issue, they expected to find that chicks would grow slower and weigh less than might be expected – or hoped.

_D062084 Lapwing

Photo: Kevin Simmonds

One of the main reasons RSPB scientists published this research was because site managers often ask for support to monitor invertebrates, in order to make sure that there is enough food for waders.  There are lots of reasons why this is extremely difficult – i) what is enough? ii) chicks are catholic in their choice of prey, going for whatever is abundant and available at the time, so what do you measure and when? iii) linking food availability to growth and survival is inevitably tricky.  The great thing about this paper is that it shows that, in general, well-managed sites will provide enough food.  If managers are worried about food availability then monitoring the growth rates of chicks and comparing their data to the published information is far easier than measuring an invertebrate resource that varies hugely in space and time.

To understand the growth rates of Lapwing and Redshank chicks, a total of 130 tags were deployed across 15 lowland wet grassland nature reserves and protected sites, within the UK, during 2009, 2010, 2012 and 2013.  This enabled family parties to be tracked and helped to yield a total of 750 monitored individuals.  All sites were managed with the aim of providing optimum conditions for breeding Lapwing and Redshank (both nesting and chick rearing).  Chicks were ringed, tagged and measured when captured and subsequently about every eight days.  Relocating the chicks involved tracking the tagged individuals and, through them, their ringed siblings.  It was harder to recapture Redshanks, which are more cryptically coloured and move around more.

Lapwing Fledglings

Two well-grown Lapwings on a wet day. Photo: Jen Smart

Lucy and her colleagues demonstrated that, on average, Lapwing and Redshank chicks achieved growth rates similar to those calculated for larger samples of chicks studied in The Netherlands and the UK, and achieved better conditions more quickly than those measured in a standardised Dutch study.  This suggests that food availability for wader chicks on well-managed lowland wet grassland sites is unlikely to be limiting chick survival and population recovery.

To understand why populations of species such as Lapwing and Redshank are failing to recover, the focus should be on other potential causes of chick mortality, such as predation or agricultural activities.  The positive message is that, if these other causes of chick mortality can be reduced, well-managed wader sites are likely to be successful in producing healthy fledglings and to facilitate population recovery.

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Body condition of tagged Lapwing chicks (centre) did not differ from that of untagged chicks in other broods, indicating that the tags (representing 2-3% of a tagged chick) and recapture frequencies did not aversely affect chick body condition or growth. Photo: Jen Smart

More feeding opportunities for chicks

There are several management options which are being used by conservation organisations and land-owners who are keen to try to support species that breed on lowland wet grasslands.  The first suite increases feeding opportunities for chicks:

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Long grass is important to nesting Redshank and their chicks. Photo Kevin Simmonds

Grazing regimes need to be adjusted to create the correct sward height, heterogeneity of structure etc. See, for instance, McCracken, D. & J. Tallowin. 2004. Swards and structure: the interactions between farming practices and bird food resources in lowland grasslands. Ibis 146: 108–114.

Increasing the height of the water table provides better feeding opportunities for adults and chicks.  See, for instance: Eglington, S.M., M. Bolton, M.A. Smart, W.J. Sutherland, A.R. Watkinson & J.A. Gill. 2010. Managing water levels on wet grasslands to improve foraging conditions for breeding northern lapwing Vanellus vanellus. Journal of Applied Ecology 47: 451–458.

Providing more wet habitat features, in the form of pools or foot-drains. See, for instance: Eglington, S.M., J.A. Gill, M. Bolton, M.A. Smart, W.J.Sutherland & A.R. Watkinson. 2007. Restoration of wet features for breeding waders on lowland wet grassland. Journal of Applied Ecology 45: 305–314 and Smart, J., Gill, J.A., Sutherland, W.J., Watkinson, A.R., 2006. Grassland-breeding waders: identifying key habitat requirements for management. Journal of Applied Ecology 43: 454-463.

Using agri-environment schemes to achieve these habitat goals. See, for instance: Smart, J.A., Wotton, R., Dillon, I.A., Cooke, A.I., Diack, I., Drewitt, A.L., Grice, P.V. & Gregory, R.D. 2014. Synergies between site protection and agri-environment schemes for the conservation of waders on lowland wet grasslands Ibis 156: 576-590. 

Reducing predation risks

A reduction in predation can be effected by direct control of species such as corvids, mustelids and foxes but other tools are also available:

Carrion crow Andy Hay rspb-images

Andy Hay/RSPB images

Removing isolated trees, telegraph posts and wires that are used as look-out perches by corvids:  Berg, A., Lindberg, T. & Kallebrink, K.G. 1992. Hatching success of Lapwings on farmland – Differences between habitats and colonies of different sizes. J. Anim. Ecol. 61: 469-476 and MacDonald, M.A. & Bolton, M. 2008. Predation on wader nests in Europe. Ibis 150: 54-73.

Using electric fences to keep out foxes and badgers. Malpas, L. R., Kennerley, R. J., Hirons, G. J., Sheldon, R. D., Ausden, M., Gilbert, J. C. & Smart, J. 2013. The use of predator-exclusion fencing as a management tool improves the breeding success of waders on lowland wet grassland. Journal for Nature Conservation: 21, 37-47.

Designing the lay-out of water features so as to reduce fox/nest interactions: Bellebaum, J. & C. Bock. 2009. Influence of ground predators and water levels on Lapwing Vanellus vanellus breeding success in two continental wetlands. Journal of Ornithology 150: 221–230.

Diversionary feeding – providing areas of long grass which act as refuges for small mammals: see other WaderTales Blog.

Decisions for the future

Lapwing nest Andy Hay rspb-images

Andy Hay/RSPB images

The majority of the chicks monitored in this study were predated before fledging.  If this mortality can be reduced then sites which are managed with wader chicks in mind have the potential to support population recovery.  Decisions upon how to reduce predation will need to be based upon the effectiveness and costs of the suite of solutions that are available, as well as ethical decisions as to which predators can be controlled and when – a potentially tricky issue for those managing nature reserves.

Mason, L.R. and Smart, J. Wader chick condition is not limited by resource availability on wader-friendly lowland wet grassland sites in the UK. Wader Study 122:3 Dec 2015


 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