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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Wetland Bird Survey: working for waders

Red-listed Curlews, Scottish Oystercatchers, a boom in Black-tailed Godwits and the need for safe roost sites. Here’s a selection of WaderTales blogs that may appeal to counters who contribute to the UK Wetland Bird Survey (WeBS) and other birdwatchers who like waders/shorebirds.

Blog RINGOS

It’s 70 years since UK birdwatchers started to count waders and waterfowl and there are now over 3000 registered Wetland Bird Survey volunteers.

WeBS70logo6a_smallThe work that volunteers do to chart the rises and falls of species as diverse as Redshanks and Whooper Swans provides a unique insight into the fortunes of our wintering waterbirds. As a tribute to the people behind the binoculars and telescopes, I highlight seven WaderTales articles that use WeBS data. Click on the links in bold if you want to read a particular story.

Curlew counts

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WeBS counts for Curlew in Great Britain between 1974 and 2016

In the blog Is the Curlew really near-threatened? WeBS counts are used to show how numbers have changed over the decades. There might have been a boost in numbers when Curlew came off the hunting quarry list in Great Britain in 1981 but declines in the last 15 years reflect issues birds face in the breeding season in many parts of their European range.

Internationally, Eurasian Curlews are classified as near-threatened and in the UK they are now red listed. WeBS counts in Northern Ireland, alongside I-WeBS counts in the Republic, were successfully used to argue for the cessation of shooting across the island of Ireland in 2012.

Scottish Oystercatchers

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Oystercatchers are unusual, amongst waders, in that they feed their young

Surely the Oystercatcher is one wader species that we don’t need to worry about? Although the blog Oystercatcher: from shingle beach to roof-top leads with nesting behaviour, WeBS counts are used to illustrate regional trends in different parts of the United Kingdom. In Scotland, there is concern about poor breeding success, while in parts of Wales and England, WeBS counts may provide a way of measuring the population-level effects of cockle fishing and diseases affecting shellfish.

oyc webs

Three very different trajectories for national WeBS counts for Oystercatchers since 1974

Mid-winter movements

figureThe annual WeBS report highlights the months in which counts are at their highest in different estuaries. For Knot, for instance, the highest counts on the Wash are in September, in other east-coast estuaries and on the Dee the peak is in December, whilst further north, in Morecambe Bay and the Solway, top numbers occur in January and February.

In Godwits & Godwiteers, which focuses on the superb work of observers who track the movements of colour-ringed Black-tailed Godwits, WeBS counts from east coast estuaries and the Ouse Washes illustrate the move inland that occurs as the winter progresses.

National patterns and local counts

blogGroups of WeBS counters who cover local estuaries will be the first to notice changes in the numbers of the key species that use their own sites. If the number of Dunlin drops, is that a local phenomenon or part of a national picture? Is there always a strong link between national declines (or increases) and site-based counts? Interpreting changing wader counts provides some answers. It emphasises just how reluctant waders are to change wintering sites between years.

High-tide roosts

horse-and-flockEvery WeBS counter will appreciate the value of a safe (undisturbed) roosting site, whether this be used by waders or by ducks and geese. In A place to roost, WeBS counts for Black-tailed Godwits are used to assess the national and international importance of an individual roosting site in northwest England. The main thread, however, is about the energy expenditure associated with sleeping (not very much) and travelling to and from a safe roost site (lots). An interesting add-on is the story of what happened to Cardiff’s Redshanks when the estuary was turned into a lake.

New recruits

If adult birds don’t change their winter homes then increases in local populations may well reflect good breeding years for wader species. 2017 seems to have been one of the good years for several species that breed in Iceland, particularly Black-tailed Godwits. WeBS counters should not be surprised if there are really high counts this winter.

T with BTGA great summer for Iceland’s waders puts this year’s productivity into context and gives an update on wader research that is being undertaken by the South Iceland Research Centre (University of Iceland), the University of East Anglia (UK) and the University of Aveiro (Portugal). If you have ever seen a colour-ringed Black-tailed Godwit, Ringed Plover, Oystercatcher or Whimbrel you may well find this interesting.

On the open shore

NEWS tableThe blog News & Oystercatchers was written to promote the Non-estuarine Waterbird Survey of 2015/16, or NEWS-III. There are a lot of waders on the shorelines that link the estuaries that are covered for WeBS and, every few years, volunteers are asked to count these birds. In NEWS-II (2006/07), it was estimated that 87% of Purple Sandpipers were to be found on the open shore (see table) with high numbers of several other species. There’s an initial assessment of the results for NEWS-III in the latest WeBS report and I look forward to writing up the results as a WaderTales blog, once a paper is published.

Links to blogs mentioned already

Many more to choose from

There are over 40 WaderTales blogs to choose from in this list. Four of these articles might be of particular interest to WeBS counters:

  • knot

    Knot migration

    Which wader, when and why? gives an overview of the migration of waders into, out of and through Britain & Ireland. The patterns help to explain why the peak numbers for Sanderling occur on the Wash in August, on the Dee in November and on the North Norfolk coast in May, for instance.

  • Bar-tailed Godwits: migration & survival  contrasts the different migration patterns of the two races of Bar-tailed Godwits that use British & Irish estuaries and explains the importance of colour-rings in the calculation of survival rates. On the other side of the world, Wader declines in the shrinking Yellow Sea shows how quickly numbers can change if the annual survival probabilities of adults fall. sum plum
  • The not-so-Grey Plover focuses on the Grey or Black-bellied Plover but the real story is about moult. British and Irish estuaries are important to huge numbers of moulting waders. WeBS counters often don’t have time to look at individual birds but, with the right camera, you can learn a lot about waders by checking out the right feathers.

Thank you

Blog Counter 1I use WeBS data a lot – in my blogs and in articles – and I appreciate the tremendous value of data collected each month by thousands of contributors. They monitor the condition of their local patches and have directly contributed to local, national and international reviews of the conservation status of wintering waterbirds. To every current and past WeBS counter – ‘thank you!’

There’s a (large) selection of papers using WeBS data here, on the BTO website. The Wetland Bird Survey is run by the BTO, in partnership with RSPB and JNCC (which acts on behalf of NE, NRW, SNH & DAERA), and in association with WWT.


 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

A great summer for Iceland’s waders?

As July 2017 turned into August, the first juvenile Icelandic Black-tailed Godwits started to arrive in the UK – soon they were everywhere. Had this been a good year for waders and wader research in Iceland?

juvvy blackwits

Flock of juvenile Black-tailed Godwits in Devon

An increasing amount of wader research is taking place in Iceland, much of which is part of an international partnership between the South Iceland Research Centre (University of Iceland), the University of East Anglia (UK) and the University of Aveiro (Portugal). Although the main focus has been on Black-tailed Godwits, Whimbrels and Oystercatchers, there is a lot more to this collaboration.

Winter into spring

january surveyThe spring season started early for Verónica Méndez, who is studying the migratory decisions made by Iceland’s Oystercatchers. About one third of these birds stay in Iceland for the winter but most are thought to migrate to Ireland and western coasts of the UK. By looking for colour-ringed individuals in January she was pretty sure that she would be sampling resident birds. There’s a blog about this project here. At the same time, sightings of migratory birds were being reported from the UK and Ireland.

Since 2000, there have been annual spring surveys of arriving Black-tailed Godwits. Jenny Gill and I arrived on 13 April and started our survey routine of regular visits to estuaries, wetlands and stubble fields in south and west Iceland. Icelandic birdwatchers cover other sites in the east and south of Iceland. The dates of the arrivals of individual birds have already contributed to a paper about what is driving earlier spring migration of the species, which is written up in this blog.

FrenchIn cold northerlies, migration from Ireland, the UK and mainland Europe was slow in 2017. This is something we have seen before and described in this blog about the appearance of large flocks in Scotland. A record number of Black-tailed Godwits – 2270 birds in total – were seen on the Scottish island of Tiree on 25 April 2017, including a minimum of 23 colour-ringed birds. We saw one of these birds four days later, fast asleep on a hay field near the south coast of Iceland.

Breeding studies

The 2016/17 winter had been relatively warm and wet in Iceland and the ground was not frozen when waders returned from Europe. The Black-tailed Godwits did not stay for long on the estuaries before moving inland to breeding territories.

The Oystercatcher project got off to an early start. oyc crossIn collaboration with Sölvi R Vignisson, Ólafur Torfason and Guðmundur Örn Benediktsson, the team colour-ringed 177 new adults and 144 chicks in a range of sites around Iceland. This year’s adults have white rings with two letters on the left leg and two colour-rings on the right, whilst chicks have grey instead of white. A smaller number of youngsters ringed in 2016 have green rings with engraved letters and some adults from previous years have green flags.

As part of a study to try to understand the migratory behaviour of young Oystercatchers, José Alves & Verónica Méndez have fitted GPS/GSM transmitters to a small number of big chicks. Which birds will migrate and what determines the strategy? Two birds have already made what appear to be exploratory trips around southwest Iceland, before returning to their natal sites.

FIRST2OYCSAt the time of writing (26 August), none of the birds with trackers has yet left Iceland but the first two colour-ringed birds have been seen in Ireland – an adult from the east and a juvenile from the south (see map).

Breeding studies of Black-tailed Godwits have been ongoing since 2001 and a small number of adults and chicks were ringed this year. This graph, which appears in the blog Why is spring migration getting earlier? showed that recent recruits to the population arrive in Iceland earlier than birds from previous generations.

timing hatching

Dates of spring arrival into Iceland of 46 individuals hatched in different years and subsequently recorded on spring arrival (reproduced from Gill et al. 2014)

Pressures on Iceland’s waders

tableIceland is hugely important for breeding waders. It holds about 75% of Europe’s breeding Whimbrel, over half of the region’s Dunlin and perhaps half of its Golden Plover. Although changes to the way land is farmed may have provided opportunities for some species, such as Black-tailed Godwits, intensification and the timing of operations have the potential to impact distribution and breeding success. A paper by Lilja Jóhannesdóttir was written up as a blog Do Iceland’s farmers care about wader conservation? and she successfully completed her PhD Links between agricultural management and wader populations in sub-arctic landscapes in June 2017.

T with BTGThe amount of woodland is changing in Iceland, with more forestry and shelter belts around summer cottages. This is an issue that was highlighted in an AEWA report published in the autumn of 2016. In the spring, Aldís Pálsdóttir started a new PhD at the University of Iceland, in which she will explore the effects of forestry on breeding waders in Iceland. Her first task in the field was to measure the effects of forest patches on breeding wader distribution, which involved walking over 400km of survey transects! Complementary work this summer by Harry Ewing, as part of his Masters in Applied Ecology and Conservation at the University of East Anglia, has explored how levels of wader nest predation vary with distance from forest patches. There’s more about the effects of woodland on breeding waders in this recent Lapwing blog: Mastering Lapwing Conservation.

Deploying and collecting geolocators to study migration

Geolocators provide a cost-effective way of collecting information on the year-round movements of individual birds, as long as birds can be recaught in the breeding season following the deployment of the tags. This blog summarises a useful paper about the safe use of geolocators.

whimbrelCamilo Carneiro is studying for a PhD at the University of Aveiro. His project, entitled Bridging from arctic to the tropics: implications of long distance migration to individual fitness, takes him to Iceland in the summer and to Mauritania and Guinea-Bissau in the winter time. By putting geolocators on Whimbrels in Iceland, he can establish the migration strategies of individuals. He has already mapped 96 migrations of 32 individual birds and we look forward to seeing the results from his studies. A flavour can be found here, in blogs about the migration of Icelandic Whimbrel and the first results of initial geolocator work by José Alves, one of Camilo’s supervisors.

RingoRinged Plovers that breed in Iceland are thought to spend the winter in southern Europe and northern Africa. Böðvar Þórisson has been studying breeding Ringed Plovers for many years, with recent work including using geolocators to explore the migration routes and timings of individuals. This year he managed to retrieve 7 of the 9 geolocators that he put on in 2016 – look out for a poster on this at IWSG 2017 in Prague. These birds had spent their winters in Mauritania, Portugal, Spain, France and southern England. 16 new tags were deployed during 2017, including a number on the same birds as in 2016.

RNPIn collaboration with Yann Kolbeinsson and Rob van Bemmelen, Jóse Alves and other members of the team have been using geolocators to study Red-necked Phalarope migration. Some birds migrate to the Pacific Ocean around coastal South America and the Galapagos but how do they get there and what is the timing of their movements? These two articles tell the story of one bird from Shetland (UK) and moulting flocks in the Bay of Fundy (Canada). Sixteen new geolocators were deployed but none of the ten deployed in 2016 were retrieved. Perhaps Red-necked Phalaropes are not that site-faithful?

So how good a breeding season was it?

2017 chick surveyAs described in this blog, the productivity of Iceland’s Black-tailed Godwits is closely linked to May temperatures – unless a volcano erupts. Each June, Tómas Gunnarsson collects information on the number of successful broods, based on a 198 km car-based transect through south Iceland. Repeating this survey in 2017 he discovered a record number of broods, adding the right-hand orange dot to the graph alongside. May 2017 was warmer than any spring during the study period covered for the IBIS paper and the number of June broods was higher too. It is not surprising that there are so many reports of juvenile Icelandic Black-tailed Godwits in Britain and Ireland this August.

For other species, where productivity is recorded in the same manner (Whimbrels, Oystercatchers and Golden Plovers), the 2017 season was also the best in the period since 2012. Perhaps other species, such as Redshank and Snipe, did well too? Will these cohorts of juveniles be big enough for there to be a detectable uplift in number on this winter’s I-WeBS and  WeBS counts?

sunset


 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

 

 

 

Flyway from Ireland to Iceland

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

Irish header

The Ireland to Iceland air link opens in February and does not close until well into May, as swans, geese, ducks, waders, gulls and passerines head north. At the end of June it opens again, with the first failed breeders returning to Ireland. Species such as Oystercatcher and Black-tailed Godwit spend much more of the year in Ireland than they do in Iceland.

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

The island of Ireland holds important populations of waders in the wintertime – everything from Grey Plovers from Siberia to Turnstones from Canada – but there is  special relationship with Iceland. It’s the next stopping off point for passage Sanderling, as they fly from Africa to Greenland, and the ultimate destination for lots of wintering birds such as Redshank and Golden Plovers.

Oystercatchers lead the way

A lot of the Oystercatchers seen around Ireland’s coastline breed in Iceland, as has been shown by the Dublin Bay Birds Project. Birds start moving north very early, as shown by the appearance of four yellow-ringed Dublin Bay birds in Tiree before the end of February this year. Migratory decisions for Icelandic Oystercatchers explains how a new Icelandic project is examining the costs and benefits of being a migrant. Irish reports of Icelandic colour-ringed birds are helping to provide answers – and the Dublin Bay birds are providing great additional data.

snipe-1Each autumn, Irish-breeding Snipe are joined by much larger numbers from the north and east. About a quarter of foreign-ringed snipe that have been found in the island of Ireland are of Icelandic origin, compared to just one out of 255 in England. 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.

whimbrel-mig-fig1Some of the last waders to use the Ireland to Iceland flyway are Whimbrels, many of which stop off in Ireland on spring migration. Whimbrels on the move summarises a 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.

Black tailed-Godwits

WaderTales was invented as a way of providing feedback to colour-ring readers who focused on Black-tailed Godwits. There are 10 blogs about the species, some of which may well appeal to birdwatchers who have spotted colour-ringed birds anywhere between Belfast Harbour and the Shannon Estuary.

pairs-mapWe are all aware that migration is getting earlier but how does this happen? Monitoring the annual arrival of individual colour-ringed Black-tailed Godwits in Iceland may well have provided an answer. Why is spring migration getting earlier? reveals that it is new recruits into the breeding population that are setting the pace; they are reaching Iceland earlier than previous generations.

Another fascinating story that is revealed by colour-ringing is the synchronous arrival of the two members of breeding pairs of Black-tailed Godwits, even if one wintered in Ireland and the other in France. You can read more here.

Breeding Waders

WaderTales were developed in East Anglia so many of the articles about breeding waders have an English feel to them. Hopefully, some of the blogs will still appeal. Anyone trying to support breeding Lapwing populations might be interested in A helping hand for Lapwings, which also talks about Redshanks.

b-header

There’s an Icelandic focus too and a new blog, which looks at the attitudes of farmers, will resonate with conservationists (scientists, birdwatchers and farmers) who are trying to work together to improve conditions for Irish breeding waders. As Icelandic farming expands, what are farmers prepared to do to support breeding waders, many of which are destined to spend the winter on Irish estuaries. See: Do Iceland’s farmers care about wader conservation?

Ireland – a special place for Curlews

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 BirdWatch Ireland, RSPB, BTO and GWCT  are focusing on this species How long will it be until breeding Curlew are lost from Ireland, completely?

The threat to the Curlew is real, especially when set in an international context. Two species of curlew are probably already extinct and other members of the Numeniini (curlews, godwits and Upland Sandpiper) are facing a similar set of problems to those that probably caused the demise of the Eskimo Curlew and Slender-billed Curlew. Why are we losing our large waders? outlines the background to a global problem.

There’s a WaderTales blog that summarises a new paper from BTO and RSPB – Curlews can’t wait for a treatment plan. Although the analyses are based on British data, the results are highly relevant to Irish Curlews.

Conservation issues

Hundreds of  birdwatchers take part in the Irish Wetland Bird Survey (Republic) and the Wetland Bird Survey (Northern Ireland). These counts identify and monitor key sites for wintering waders – and wildfowl. 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. 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.

Further reading

b-stubble-godwitsHopefully, this summary  gives a flavour of some of the issues being faced by Irish 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 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.

And finally …

There’s a useful summary about wader migration to, from and through Ireland in Which wader, when and why?

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.

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.

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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.

WaderTales: a taste of Scotland

What happens when Black-tailed Godwits cannot cross the Atlantic?

ORGOLO

Observations from Tiree by John Bowler and others gave a unique insight into what happens if northerly winds set in at migration time. Here is the blog.

Here are four more uniquely Scottish WaderTales blogs

scottish-wadertalesEstablishing breeding requirements of Whimbrel  focuses on the different habitat needs of adults and chicks in Shetland.

Oystercatchers: from shingle beach to roof-tops details significant declines in Scotland, at least partly explained by predation. An increasing number have now taken to nesting on roofs.

UK Dotterel numbers have fallen by 57% presents the results of an RSPB survey that was published in Bird Study.

Prickly problems for waders explains how SNH are trying to deal with introduced Hedgehogs in the Outer Hebrides, where they are a major problem for breeding waders.

And here are another nine which may well appeal to Scottish birdwatchers:

  • NEWS and Oystercatchers focuses on the waders that  winter on coasts, instead of estuaries. It was written to promote the 205/16 coastal survey run by BTO.
  • A place to roost discusses the importance of safe, high-tide roosts, especially in terms of energetics. What are waders looking for?
  • The not-so-Grey Plover focuses on the moult of the Grey Plover but the principles are relevant to determining the ages of birds of other species.

There are over 40 WaderTales blogs. The intention is to add one or two new blogs each month. You can sign up to receive an e-mail notification when a new one is published.


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.

Oystercatchers: from shingle beach to roof-top

After over 150 years of successful exploitation of new breeding areas, there are signs that UK Oystercatchers are experiencing predation problems in the Scottish hills and facing disease-related issues on at least one Welsh estuary.

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Oystercatcher parents can fly off in search of food for chicks (Tómas Gunnarsson)

There are Oystercatchers flying over our Norfolk garden with worms to take back to their chicks, travelling up to a mile each way on feeding trips. This commuting behaviour opens up nesting opportunities not available to more conventional wader chicks which find food for themselves, albeit with some coaching. A pair of Oystercatchers can nest on the island of a former gravel pit and move up and down a river valley, to feed in wet grassland, pastures and arable fields, or hatch their chicks on the flat roof of a school and probe for worms on the playing fields. This flexibility has facilitated the spread of the species in England, and may be helping to compensate for declining numbers in the core breeding areas of Scotland.

A 150-year story of expansion

P1000520The Oystercatcher is a very distinctive and noisy bird. When pairs move into new areas they get noticed, providing us with a reliable history of their range expansion over the last two centuries. We might not now be surprised to see breeding pairs well inland, in lowland river valleys or on upland sheep pasture, but these were solely coastal breeders until about 1840, when the first pairs were recorded inland of the north Grampian coast. This nesting behaviour spread within Scotland and reached the English side of the Solway in about 1900 and Northumberland twenty years later.  You can read more in The Historical Atlas of Breeding Birds

The left-hand map below, from Bird Atlas 2007-11, illustrates the continuation of the expansion of the Oystercatcher breeding range between 1968-72, when the first few pairs had established themselves on gravel pits in the English Midlands, through to 2008-11, when pairs were well spread through English counties north of the M4. Oystercatchers have continued to colonise new counties; areas occupied over the last forty years are shown as red triangles, with larger ones being more recent.

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Maps of Oystercatcher breeding distribution from Bird Atlas 2007-11, which was a joint project between the Briitish Trust for Ornithology, BirdWatch Ireland and the Scottish Ornithologists’ Club

At first glance, all looks well. However, the right-hand map, which shows the change in abundance between the breeding season surveys of 1988-91 and 2008-11, tells a different story. Densities have been increasing in England (pink colours – darker means higher increase) but there have been major declines across much of Scotland (grey colours – darker means bigger drop).

websAlthough there has not been a large drop in the number of wintering Oystercatchers across the whole of the United Kingdom, the declining number of breeding birds in Scotland may well be to blame for the drop in winter Wetland Bird Survey (WeBS) counts for the country.  The graph alongside suggests that Scottish estuary counts are down by nearly 50% since the peak counts of 2002/03.

Breeding Season

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Schematic summary of migration of Oystercatchers ringed or recovered in Britain & Ireland, from Time to Fly by Jim Flegg (BTO)

Oystercatchers nest early in Britain and Ireland and most will have been on territory for several weeks by the end of March. At the same time, there can still be big flocks on the coasts. Some of these are young birds, which won’t breed until two or three years of age, but others will be adults that are fattening up in preparation for migrations to countries such as Iceland and Norway.  Oystercatchers breed beyond the Arctic Circle and all the way to the northern tip of both countries, where spring arrives several weeks later than it does in the UK.

Vero Oyc.jpg

Verónica Méndez-Aragon

When choosing a territory, a pair of Oystercatchers will look for food and somewhere to place a nest. The archetypal nest site might be on a beach, where the eggs blend in with the shingle that forms the nest cup, marine invertebrates can be collected from below the high tide-line and earthworms may be available on near-by fields, golf-courses or lawns, but the species has learnt to breed in a wide range of habitats.  When selecting somewhere to lay a clutch, usually of 2 to 3 eggs, a simple stretch of the imagination can turn the image of a beach into a river-bank, a gravel track or a bare patch in a field.

Ben Darvill

Three Oystercatcher chicks on the roof of The Cotterell Building at the University of Stirling (Ben Darvill / BTO Scotland)

Adding in a third dimension takes Oystercatchers to the flat roofs of buildings, such as those of Stirling University.  Here, all that lies between the fox-free shingle roof and worm-rich lawns below is a vertical drop for the chicks, when they are old enough. High-rise living is an international trait in Oystercatchers; one of the birds ringed in Norfolk by the Wash Wader Ringing Group nested in a window-box in Norway and the practice of roof-nesting is common in the Netherlands.

Oystercatchers look after their chicks for much longer than other wader parents.  Most wader chicks start finding their own insect food from day one, following their parents as they learn to pluck prey from the undersides of plant leaves or from the surface of mud and grass mosaics. Oystercatcher chicks expect a lot of their food to be brought to them. Roof-nesting chicks have no choice other than to wait for dinner to be delivered whilst those on the ground are able to do some of the work themselves.  Youngsters will beg for food for several weeks, even when they can fly, extending the parenting period beyond that which is normal for most waders. The team studying the changing migratory behavior of Icelandic Oystercatcher has found youngsters on mussel beds begging for food in October. (See Migratory Decisions for Icelandic Oystercatchers)

Population Trends

The Oystercatcher is an amber-listed species of conservation concern in the UK, to reflect the importance of these shores to the European breeding population of the species and their reliance outside the breeding season on a small number of estuaries. Although we know that individuals can live for up to 40 years, all is not completely rosy for the species, with predation and food supplies causing problems.

SAMPLED_5990014_300____As has been discussed in the recent Moorland Forum, ‘Understanding Predation report, declines in Oystercatcher numbers have occurred in some moorland parts of the range and there has been a drop in numbers of 29%* across Scotland as a whole, since the start of the Breeding Bird Survey in 1995.  The English population had increased by 56%* in the same period but this does not compensate for the numerically larger losses from the core northern areas. Local representatives and researchers who contributed to the Moorland Forum report highlighted crows, foxes, buzzards and ravens as the four main predators that threaten the success of breeding Oystercatchers.

(* figures for 1995-2015 updated to -37% Scotland and +50% England)

Coastal food supplies are critical for Oystercatchers in the winter months and for at least the first two summers of a young bird’s life.  While they take a wide range of shellfish and worms, one of the key elements of the diet on many estuaries is cockles. In the past this has brought Oystercatchers into conflict with cockle fisheries. There was a major controversy in the 1970s when, at the behest of cockle fishers and despite the objection of conservationists in the UK and in Norway, permission was given to shoot 10,000 Oystercatchers on the Burry Inlet in South Wales – and embarrassment when cockle numbers continued to decline.

5-Cockle

These cockles have died very recently (image from CEFAS report)

The latest cockle problem is affecting both birds and people, again on the Burry Inlet but also in sites as far apart as the Dee, the Wash and the Dutch coast. Mass die-offs of young cockles are happening in most years, caused by three new parasites, first identified in Spain, America and Portugal, the worst of which causes the haplosporidian infection. In the five winters up until 1999/2000, the average peak count for Oystercatcher on the WeBS count on the Burry Inlet was 17,188, dropping in each of the next three periods to reach 12,195 in the five years up until 2014/15. This represents a 30% decline.

With no available treatments and with the parasites spreading into new areas, life could get tough for human cockle-gatherers and flocks of Oystercatchers, which rely on shellfish for their income and survival, respectively. You can read more about these issues in a CEFAS report which focuses on the Burry Inlet.

Summary: caring, spreading, declining and threatened by disease

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Unlike most wader parents, Oystercatchers find food to feed to their chicks (Tómas Gunnarsson)

  • Cockle die-offs have not as yet had a major, national population-level effect on wintering Oystercatchers but the presence of this threat to Oystercatchers and to other species that feed on young cockles, such as Knot and Turnstone, emphasises the need for continued monitoring and the value of WeBS counts.
  • Breeding Oystercatchers are in decline in the uplands and there is agreement that the role of predators in the moorland environment needs to be better understood. The Moorland Forum report mentioned above also focuses on four red-listed species: the near-threatened Curlew (see separate WaderTales blog), Lapwing, Grey Partridge and Black Grouse.
  • The Oystercatcher has been successfully expanding its breeding range and making use of new nesting opportunities for at least 150 years. Increases in England are, to some extent, compensating for declines in Scotland.
  • The fact that parents collect food for their young opens up breeding opportunities in areas where there are inadequate supplies of food adjacent to safe nesting sites. Clever birds!

This is a modified version of an article that first appeared in Shooting Times & Country magazine.


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.

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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

NEWS and Oystercatchers

It’s amazing what you can find when walking along a beach with a pair of binoculars

Curlew in snow

Curlews waiting for the tide to drop: Graham Catley

Thousands of British and Irish birdwatchers visit estuaries but there’s a lot of coastal habitat that gets little attention.  That’s where you’ll find 87% of the UK’s Purple Sandpipers, over half of the Turnstones and nearly half of the Ringed Plover – or those were the figures nine years ago.  It’s time to update these estimates, which is where NEWS-III came in. That’s the catchy name for the third Non-estuarine Waterbird Survey, which operated in the UK and Ireland over the period 1 Dec 2015 to 29 Feb 2016.

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We’ll be looking out for colour-ringed Oystercatchers: Tómas Gunnarsson

We covered 6 beach sections as our contribution to NEWS-II over the Christmas period 2006/07: three horrible stretches right next to the main A78 along the Clyde coast and three lovely beaches on the island of Cumbrae. We found 57 waders on the first set, while dodging the traffic, and 184 on a very relaxed day trip from Largs by ferry. There were comparable numbers of Curlew, Turnstone and Redshank but more Oystercatchers on the wider, island beaches.  That’s where we also found our only Ringed Plover, as well as 11 Purple Sandpipers and 3 Lapwing.

cumbrae comparisonThis year, we found far fewer waders than nine years ago. The table alongside provides a comparison for the three sections that we covered on Cumbrae for NEWS II and NEWS III. We failed to find any Purple Sandpipers in any of the 17 sections of the Clyde coast that we covered but were surprised to see a total of 5 Greenshanks. There seemed to be far fewer seabirds too. This is just a tiny snap-shot that may not be representative of the picture across the whole of the coastline of Britain & Ireland. Let’s hope that, despite the stormy weather, there was sufficient coverage for robust anlayses to be carried out by BTO staff.

RP WeBSWe know that wader number on estuaries are changing.  For instance, in the last few years, numbers of Ringed Plover in the UK have been falling (see figure).  The declining line indicates a significant drop but it won’t be quite such a concern if this year’s NEWS-III surveyors find that there are now more Ringed Plovers on open coasts.  That may seem like an optimistic suggestion, unless you look at changes between NEWS (1997/98) and NEWS-II (2006/07).  During this period, at the same time that WeBS counts of estuaries were falling, there was actually a 25% increase in Ringed Plover numbers on open coast.  Perhaps this redistribution from estuaries to open coasts has continued?

NEWS tableTwenty-one species of wader were recorded during NEWS-II, with Oystercatcher being the most numerous with an estimated total of 64,064 for the whole non-estuarine coastline of the UK. The full report is available on the BTO website .  With support from hundreds of volunteer birdwatchers it was possible to make population estimates for the 12 most numerous species, including the non-estuarine specialists, Ringed Plover, Sanderling, Purple Sandpiper and Turnstone.  These four species accounted for estimates of 15,230, 6,295, 11,306 and 30,122 individuals respectively.  The table alongside shows the intertidal-zone totals and the percentage of the total UK population that each estimate comprises, based on Population estimates of birds in Great Britain & the United Kingdom by Musgrove et al which was published in British Birds.

Five of the species that were in the top 12 for NEWS-II have been categorised as near-threatened by IUCN/BirdLife.  Oystercatcher is the most numerous of the five, with over 64,000 in intertidal areas of the open coast, representing nearly 20% of the national wintering population.  There are relatively small numbers of Bar-tailed Godwit, Lapwing and Knot but 26,744 Curlew is equivalent to 17.8% of the UK total.   There’s a WaderTales blog about the near-threatened designation of Curlew.

Turnstone Belsey

59% of the UK’s Turnstone ar found on the open shore: Derek Belsey/BTO

Unfortunately for the scientists who organised NEWS-III there is a huge disparity between the distribution of birdwatchers and the number of coastal stretches that would ideally be surveyed, so let’s hope a good number of English birdwatchers decided to spend a few days in Scotland over the survey period.  Three-quarters of the open coast in the UK is in Scotland (all those crinkly bits, sea-lochs and islands) with Northern Ireland, England and Wales respectively having approximately 2.3%, 16.0% and 6.6%.  Taking account of the spread of the available sites, there’s a relatively uniform UK-wide distribution of most species, although  Sanderling has a southerly bias to its distribution and Purple Sandpiper a strong northern bias.

NEWS-III was not just about waders; volunteers were asked to record other waterbirds too. Our counts for NEWS-II covered Cormorant and Shag, Mute Swan, Eider, Red-breasted Merganser, Wigeon, Mallard, Guillemot and Grey Heron.

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Data from BTO ringing report

Whilst I was delighted to use WaderTales to promote NEWS-III, there was an ulterior motive. We wanted counters to look out for Oystercatchers wearing colour rings. Icelandic Oystercatchers can be encountered almost anywhere but the ones in England are very much outnumbered by those from Norway, the other main source of wintering birds. The table alongside gives an idea of the north-westerly distribution of birds with an Icelandic origin.

oycmap.pngColour-ringed Icelandic Oystercatchers are part of a new project to look at how climate change might be affecting migration patterns. There’s a blog about the project here. The map alongside shows where colour-ringed birds from the study areas in Iceland have already been found, with most in Scotland and Ireland.  Birds will either be wearing 3 colour-rings and a green or white flag or two colour-rings and an engraved darvik.

NEWS only happens every few years so this was a great opportunity to contribute to our understanding of the conservation status of some important species, several of which are now near-threatened. I am looking forward to the results with interest, and a little concern.


 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

Migratory decisions for Icelandic Oystercatchers

New Oystercatcher research in Iceland aims to explain how migration patterns change over time and how individual behaviour may drive population change

Which Oystercatchers will cross the Atlantic and which will stay in Iceland? (Tómas Gunarsson)

Which Oystercatchers will cross the Atlantic and which will stay in Iceland? (Tómas Gunarsson)

Most waders leave Iceland in the autumn, with vast numbers heading for the British Isles, coastal Europe and even Africa.  Amongst the exceptions are hundreds of Oystercatchers which ‘tough it out’ in wintry conditions, thereby saving themselves two long trans-Atlantic flights and potentially ensuring that they are able to make a prompt start to the next breeding season. Why do some Oystercatchers migrate when others don’t?  Is it the same birds each year?  Do resident birds have a competitive advantage when it comes to choosing a territory and raising chicks, and do these chicks follow the same migratory strategy as their parents?  In an era of changing weather patterns, can birds change their migratory preferences and how does this happen?  These are some of the questions that are being tackled by Verónica Méndez, as she monitors the movements of colour-ringed individuals in a joint University of East Anglia (UK) / University of Iceland / University of Aveiro (Portugal) project.

Migration in a changing world

Throughout the world, the distribution, abundance and behaviour of species is changing, partially as a response to climatic change. Given that most bird protection relies on a legislative framework that is site-based, changes to bird distributions are going to make life challenging for conservationists.  Will today’s Special Protection Areas be fit for purpose in 20 years’ time?  As they look to the future, conservationists want to be able to set up a network of sites that can flexibly support migratory species, and this entails understanding why and how migratory patterns are changing and might change in the future.  Icelandic Oystercatchers may well provide an ideal model species through which scientists can learn how migratory decisions can influence individual fitness, population demography and species distribution.

“I’m sure that I started a nest scrape somewhere here”. Spring conditions in 2015 were distinctly wintry: Verónica Méndez

There are likely to be different pressures facing resident and migratory Oystercatchers.  Two birds that breed on adjacent territories might have completely different annual cycles.  The bird that spends the winter in Iceland will not have to migrate but its probability of survival may be reduced by harsher winter conditions, possibly with a more limited set of feeding options and certainly with shorter periods of daylight.  In mid-winter, there is 6hr 40 min between first light and dusk in Reykjavik but 9 hours in Bangor, North Wales.  Come the spring, however, the same bird will be well placed to take advantage if spring comes early, whilst his migratory neighbour will face a hazardous sea-crossing, perhaps being delayed by a fortnight or more if strong northerly winds set in.

Individuals matter

An adult Oystercatcher providing food for a growing chick (Tómas Gunnarsson)

An adult Oystercatcher providing food for a growing chick: Tómas Gunnarsson

Although patterns of change in migratory strategies can be detected by looking at timings of first arrival and counting flocks, these changes can only be explained if we understand what individuals are doing.  It will be interesting to see, for instance, if Icelandic-winterers pair up together and what their offspring subsequently do in their first autumn.  Oystercatchers look after their chicks for longer than most waders so perhaps youngsters will be more likely to adopt the strategy of their parents than other species?

To answer these and many other questions, Verónica and colleagues from the Universities of East Anglia, Iceland and Aveiro have been colour-ringing Oystercatcher adults and chicks on the breeding grounds between the north-west and southern lowlands of Iceland.  Both adults and chicks (when big enough) are ringed with two colour rings on the left tarsus and a flag above another colour ring on the right tarsus (metal ring goes on either tibia and is not part of the scheme).  See update below to learn about a second scheme.

Wintering flocks of Oystercatchers will be checked in Iceland but most of the colour-ringed birds are likely to have flown south.  The team therefore need birdwatchers around the British Isles and along the Atlantic coast of Europe to look out for these marked Oystercatchers and to report them to icelandwader@gmail.com

Catching adult Oystercatchers

The study season for an Oystercatcher fieldworker starts in April, when the first nests start to appear.  Once a full clutch of between 1 and 4 eggs has been produced, both parent birds take turns to incubate for between 3 and 4 weeks.  During this period it is possible to catch the adults by temporarily replacing the eggs with plastic eggs and setting a spring trap or walk-in trap over the nest.  Sometimes the second adult can be caught while the first bird is being ringed, as he or she settles down on the unattended eggs.

Juvenile wearing new colour rings: Verónica Méndez

Juvenile wearing new colour-rings: Verónica Méndez

Catching chicks is harder.  Although they can be metal-ringed at an early age, their legs are too short at this stage for additional colour-rings.  By the time that the youngsters are big enough they can run very quickly – or even fly – providing excellent entertainment for the ‘spotter’ in the research team, as the ‘chaser’ is often outwitted and out-run.

What has been learnt so far?

The first adult Oystercatchers were colour-marked in the summer of 2012 and more were ringed in 2013 and 2014.  In the winter of 2014-15, eight migratory individuals were seen in Ireland, Northern Ireland, Wales, Scotland and Shetland and five resident birds were shown to have stayed in Iceland. Additionally, five birds wearing BTO rings that they acquired in Ireland and Wales have been recruited to the colour-ring project, increasing the sample of known migrants.  By the end of 2015, over 200 adults had been colour-ringed, as well as about 100 new chicks, so there should be plenty of birds to look for this winter.

Breeding adult Oystercatcher: Tómas Gunnarsson

Breeding adult Oystercatcher: Tómas Gunnarsson

A century or more of metal-ringing has shown that Icelandic Oystercatchers migrate mostly to the British Isles and West coast of France, but some have been recovered in Germany, The Netherlands, Spain and Portugal, so please check out any Oystercatcher flocks you see in any of these countries.  Although most observations of colour-ringed Oystercatchers will be made during the winter months, young birds may well be spotted in the summer, as Oystercatchers do not start to breed until they are two or more years old.  If some juveniles winter in Iceland perhaps they might be able to breed at a younger age than their migratory cousins?  That would be yet another way for a change in strategy to not only impact on the fitness of the individual but also on the population demography and the overall migratory strategy of the species.

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

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

An update…

Oystercatchers caught in later catches have been ringed with white, grey or green engraved rings, alongside two colour-rings.  If you come across a bird with a yellow engraved ring then it is probably from a project in Dublin Bay.

When researchers from the two projects got together at the 2015 International Wader Study Group Conference in Iceland they realised that five more Dublin Bay birds could be added to the list of Icelandic breeders that are definite migrants.

Please check flocks of Oystercatchers and report any sightings to icelandwader@gmail.com

Photo: Tómas Gunnarsson

Photo: Tómas Gunnarsson


 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