Wader declines in the shrinking Yellow Sea

An important paper by Colin Studds and colleagues shines a spotlight on the Yellow Sea, where waders/shorebirds have lost vast areas of feeding habitat during China’s economic boom.

headerWaders make some of the most remarkable migratory journeys in the bird world and many rely on a few key estuaries to refuel, especially as they head north to breed. For hundreds of thousands of waders on the East Asian-Australasian Flyway, from tiny Red-necked Stints to Far Eastern Curlews, the Yellow Sea is absolutely crucial. A new paper by Colin Studds and sixteen colleagues collates the available information on current population trends of waders using this flyway and shows how these relate to the reliance of each species on the Yellow Sea. The more a species relies on disappearing mudflats, between China and the Korean peninsular, the faster it is declining.

As Colin Studds says: “Scientists have long believed that loss of these rest stops could be related to the declines, but there was no smoking gun.” Now there is. The new paper is published in Nature Communications.

Rapid population decline in migratory shorebirds relying on Yellow Sea tidal mudflats as stopover sites (Nature Communications 8:14895 | DOI: 10.1038/ncomms14895)

Establishing the routes

barwit

Bar-tailed Godwits make epic migratory journeys

Over the last twenty years, satellite tracking has revealed the amazing migratory journeys of shorebirds on the East Asian-Australasian Flyway. The most famous wader ever must be E7, which was the first Bar-tailed Godwit to be tracked from Alaska to New Zealand in one continuous journey, covering the 11,600 km journey in 9 days. When E7 flew from New Zealand to the Yellow Sea in the next spring, on the first leg of its return journey, that was another flight of 10,200 km in 7 days.

It’s not just Bar-tailed Godwits that link New Zealand and Australia to the Yellow Sea. Colour-ringing has established that at least 10 wader species use this staging area during their northward migration in spring.

Counts by Birdwatchers

FE Curlew standing

Far Eastern Curlew is one of the fastest declining species on the flyway. There is a WaderTales blog about the global plight of members of the curlew/godwit family here.

Annual counts of waders have been taking place in sites across Australia and New Zealand since the early 1980s. Colin Studds and his colleagues use data collected during the non-breeding seasons between 1993 and 2012 from 43 of these key locations. The analysis relies on the work of scores of volunteer birdwatchers who undertake these counts during the months from October through to March. The count data used in this paper focused on December and January, when there is least likelihood of within-season movement. Some of the declines have been dramatic; in twenty years, the number of Far Eastern Curlew fell by about 60%, with a 75% drop in Curlew Sandpipers, just to give two examples.

If numbers are going down, then that suggests that these waders are failing to breed as successfully as they once did or that the adults themselves are dying in larger numbers than used to be the case – or both. The fact that no changes have been observed in the proportion of juveniles in flocks strongly suggests that survival rate is the key demographic parameter upon which to focus when trying to understand population declines.

Declining survival rates

Colour-ring observations not only establish migratory links, they also provide the raw data from which annual survival rates can be estimated. A typical annual survival rate for an adult wader is between around 70% and 90%. If the survival rate is 90%, and 50 female waders lay an average of 4 eggs during a breeding season, then only 10 of the chicks need to hatch and reach breeding age for the population to remain stable. If that same level of productivity occurred but the survival rate for adults changes to 80%, then the chance of an adult dying in any given year doubles and the population will drop by half in just six years. This illustrates that a fall in survival of just 10% can have serious implications for the population trajectory.

great knot

Changing Great Knot survival from 86% to 68% could reduce life-expectancy by two-thirds

The counts of non-breeding waders in Australia suggested that there were major changes in numbers for several species between 2010 and 2012. When Theunis Piersma and colleagues analysed the colour-ring sightings for populations of three species that spend the non-breeding season in Australia and breed in eastern Siberia – Bar-tailed Godwit, Great Knot and Red Knot – they discovered a decline in annual survival of between 18% and 19% in just two years. Their paper raised serous alarm bells. All three populations spend time in the Yellow Sea on their spring migration and Theunis argued that rapid habitat loss in the Yellow Sea was the most likely explanation of reduced summer survival, with dire (but uncertain) forecasts for the future of these flyway populations.

survival table

Reliance on the Yellow Sea

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Bar-tailed Godwits watch on as their habitat disappears (Dave Melville)

It is estimated that nearly 30% of Yellow Sea tidal mudflats have been lost to coastal development in the last 30 years and China is forecast to undergo up to 14% expansion in urban development over the next 15 years, much of it concentrated on the margins of the Yellow Sea. Within the remaining mudflats, there have been increases in algal blooms, heavy metal deposits and areas of invasive Spartina alterniflora, the last of which reduces mudflat availability. All of these changes have the potential to put huge pressures on waders that are fattening up for the last leg of their migratory journey to arctic breeding grounds.

Previous work focused on waders in Japan, by Tatsuya Amano and colleagues, had shown that wader species relying on the Yellow Sea while on migration are declining more quickly than those that are not but Japan is on the migratory flyway so this result could have been confounded by changes in migratory route. By using data from the the non-breeding season and looking at a wider range of species, Colin Studds and his colleagues have been able to link reliance on the Yellow Sea with the magnitude of population changes.

Main graphA key element of the new paper is the compilation of available data on flyway population sizes, migratory connectivity and Yellow Sea count data, in order to estimate the proportion of each species that rely upon the Yellow Sea. At the lowest end is the Grey-tailed Tattler, only 3% of which use the area, whilst 100% of the menzbieri subspecies of Bar-tailed Godwit rely on the Yellow Sea. When reliance is plotted against annual population trend the fit is remarkable. Interestingly, there are two very similar subspecies in the analysis; whilst the menzbieri Bar-tailed Godwits are estimated to have been declining by 6.1% per annum, the baueri subspecies, which is only 50% reliant on the Yellow Sea, has ‘only’ been declining at 1.4% per annum. 

Emerging Conservation Action

Good newsThis paper provides further evidence of the huge importance of the Yellow Sea. To quote Richard Fuller, the team leader of this research “Every country along the migration route of these birds must protect habitat and reduce hunting to prevent the birds declining further or even going extinct.”  Issues facing birds that use the flyway are being successfully highlighted by the East Asian-Australian Flyway Partnership. Australia has signed agreements with China, Korea and Japan to protect migratory birds, and China and South Korea have recently begun the process of listing parts of the Yellow Sea as World Heritage Sites. As well as development controls, a range of mitigation actions are discussed in the paper – let’s hope that they are pursued with enthusiasm.

The paper is free to download

GK flockThe results of this study have been published as Rapid population decline in migratory shorebirds relying on Yellow Sea tidal mudflats as stopover sites (Nature Communications 8:14895 | DOI: 10.1038/ncomms14895)

The authors are: Colin E. Studds, Bruce E. Kendall, Nicholas J. Murray, Howard B. Wilson, Danny I. Rogers, Robert S. Clemens, Ken Gosbell, Chris J. Hassell, Rosalind Jessop, David S. Melville, David A. Milton, Clive D.T. Minton, Hugh P. Possingham, Adrian C. Riegen, Phil Straw, Eric J.Woehler & Richard A. Fuller.


 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

 

Why are we losing our large waders?

A review of the global threats to the world’s Numeniini (curlews, godwits & Upland Sandpiper) has just been published. It does not make for good reading.

gambia-whimbrel

Icelandic Whimbrel in the warm conditions of The Guinea-Bissau

It is estimated that hundreds of thousands of Eskimo Curlews were migrating the full length of the two American continents 150 years ago – but the species is now probably extinct. The Slender-billed Curlew, its old-world cousin, is elusive at best and extinct at worst. According to the most recent global figures (as reported to the Convention on Migratory Species 11th Conference of the Parties, details below), there are estimated to be only 10,000 remaining Bristle-thighed Curlews, 32,000 Far Eastern Curlews and 77,000 Hudsonian Godwits. Why are we losing our large waders?

b-curlewThe perilous plight of members of the curlew family has been highlighted in WaderTales before (see Is the Eurasian Curlew really near-threatened and Dutch Black-tailed Godwit numbers down by nearly 75% for instance). Now, a group of wader/shorebird experts have analysed the wider conservation concerns for this group of large, long-lived waders. In a new review in Bird Conservation International, scientists ask if there are shared threats to the Numeniini (the Upland Sandpiper, eight curlews and four godwits). Can their findings help to explain why so many of these 13 species are at risk or, in the case of the Eskimo Curlew and Slender-billed Curlew, probably already extinct?

The Numeniini

categories2The Numeniini waders span the globe. In the table alongside you can see that the conservation status of the group covers the full range of possible levels, from Eskimo Curlew, the last definite report of which was in 1963, to six species that are listed as being of ‘least concern’ (IUCN criteria). Even these six species are far from safe, according to a new review undertaken by 35 authors, supported by expert opinion from a further 80 shorebird ecologists. The drivers that have led to the declines of several endangered and vulnerable species are already affecting others that are currently categorised as being of ‘least concern’. There’s more about these important caveats further down this blog.

The crisis for the Numeniini is worrying wader biologists, ornithologists and ecologists – and some governments. They are working together to share information, identify gaps in knowledge, drive forward new research and to push for conservation activities that can reduce the pressures on these species, and others that share the same habitats. A key output is a newly-published paper, led by the British Trust for Ornithology’s James Pearce-Higgins but with authors from almost 30 organisations across five continents, who collated knowledge from over 100 experts:

barwit-eaafp

There is already a great deal of concerted international action to save Numeniini species. This flyer was produced by the East Asian-Australasian Flyway Partnership

A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds. Bird Conservation International. ISSN 0959-2709

The authors are: JAMES W. PEARCE-HIGGINS, DANIEL J. BROWN, DAVID J. T. DOUGLAS, JOSÉ A. ALVES, MARIAGRAZIA BELLIO, PIERRICK BOCHER, GRAEME M BUCHANAN, ROB P CLAY, JESSE CONKLIN, NICOLA CROCKFORD, PETER DANN, JAANUS ELTS, CHRISTIAN FRIIS, RICHARD A. FULLER, JENNIFER A. GILL, KEN GOSBELL, JAMES A. JOHNSON, ROCIO MARQUEZ-FERRANDO, JOSE A. MASERO, DAVID S. MELVILLE, SPIKE MILLINGTON, CLIVE MINTON, TAEJ MUNDKUR, ERICA NOL, HANNES PEHLAK, THEUNIS PIERSMA, FRÉDÉRIC ROBIN, DANNY I. ROGERS, DANIEL R. RUTHRAUFF, NATHAN R. SENNER, JUNID N. SHAH, ROB D. SHELDON, SERGEJ A. SOLOVIEV, PAVEL S. TOMKOVICH and YVONNE I. VERKUIL

A model for collaborative conservation research

Identifying the causes of the problems of the Numeniini is not easy. Species such as the Little Curlew breed in some of the most remote areas of the world, whilst the wintering areas of Bristle-thighed Curlews are spread across the Pacific islands. Understanding the full annual cycle requires international cooperation, willingly provided by scientists and volunteer ornithologists who share a common concern about these species.

iwsgOne of the key elements of the paper-production process was a workshop at the 2013 International Wader Study Group conference in Wilhelmshaven, Germany. This was led by Nicola Crockford, Principal Policy Officer at RSPB, James Pearce-Higgins (BTO), Daniel Brown (RSPB), David Douglas (RSPB) and Jennifer Gill (University of East Anglia). It was preceded by a questionnaire survey of experts throughout the world, conducted by Daniel Brown and funded by RSPB. This two-stage process brought together information relating to population trends, demographic parameters (e.g. nesting success and survival rates) and actual/potential conservation threats.

cop11James, Dan and David refined the summary, bringing it together as a ‘Conservation Statements for Numeniini Species’ which was presented to the 11th Conference of the Parties of the Convention on Migratory Species in Quito, Ecuador in 2014 (CMS COP11). This report, authored by Daniel Brown, Nicola Crockford and Robert Sheldon and published on behalf of BirdLife International and the International Wader Study Group is available here.

In the figure below you can see a snapshot of the range of information that is available in the Conservation Statements, in this case for Black-tailed Godwit . In particular, this COP11 document provided background information for two species for which CMS Concerted and Cooperative Actions were being proposed – Far Eastern Curlew and Bar-tailed Godwit. It also painted a backdrop to the CMS Programme of Work on Migratory Birds and Flyways.

cop-for-blackwit

The new BCI paper aims to highlight the crises facing the Numeniini, to outline the suite of threats to the group and to promote this collaborative form of expert-led synthesis. It contains details as to how the questionnaire and workshop sessions were organised – information that will hopefully be of use to scientists studying other groups and taxa.

Findings of the review

In order to help inform conservation management and policy responses, James Pearce- Higgins and his collaborators have reviewed the threats that members of the Numeniini face across migratory flyways. They show that most threats are increasing in intensity. This is particularly the case in non-breeding areas, where habitat loss (resulting from residential and commercial development), aquaculture, mining, transport, disturbance, problematic invasive species, pollution and climate change were regarded as having the greatest detrimental impact. Fewer threats (mining, disturbance, problematic non-native species and climate change) were identified as widely affecting breeding areas.

far-eastern-curlew

An endangered Far Eastern Curlew in Australia

Numeniini populations face the greatest number of non-breeding threats in the East Asian-Australasian Flyway, especially those associated with coastal reclamation. Related threats were also identified across the Central and Atlantic Americas, and East Atlantic flyways. Threats on the breeding grounds were greatest in Central and Atlantic Americas, East Atlantic and West Asian flyways. Based on these threats, several key actions were proposed:

Three priority actions for monitoring and research:

  • To monitor breeding population trends (which for species breeding in remote areas may best be achieved through surveys at key non-breeding sites).
  • To deploy tracking technologies to identify migratory connectivity.
  • To monitor land-cover change across breeding and non-breeding areas.
eaafp

The East Asian-Australasian Flyway Partnership is a key focus for conservation action

Two priority actions focus on conservation and policy responses:

  • To identify and effectively protect key non-breeding sites across all flyways (particularly in the East Asian-Australasian Flyway).
  • To implement successful conservation interventions at a sufficient scale across human-dominated landscapes for species’ recovery to be achieved.

If implemented urgently, these measures, in combination, have the potential to alter the current population declines of many Numeniini species.

What is in the BCI paper?

As well as outlining a methodology which may well provide a template for the conservation of other groups of threatened species, the paper contains a comprehensive assessment of the global and local threats faced by the Numeniini. The discussion is the largest section – covering disturbance, development, pollution, terrestrial land-use change & predation, climate change impacts & mitigation, and hunting & harvesting. It provides an opportunity to assess the scientific evidence that supports expert opinion and usefully acknowledges some key gaps worthy of further investigation (e.g. drivers of change in the Central Asian Flyway and uncertainty over the population-level impacts of disturbance).

To summarise in a few bullet points:

  • b-davemelville

    Bar-tailed Godwits in the Yellow Sea. Another large slice of mudflat disappears as a new sea-wall is built. Read more here.

    37 populations of curlews, whimbrels, godwits and upland sandpiper are assessed.

  • Of the 13 species, seven are of conservation concern (from near-threatened to possibly extinct).
  • Most of the threats identified by the expert panel are considered to be increasing in intensity, especially in non-breeding areas.
  • A greater range of threats was reported in non-breeding areas than breeding areas.
  • Numeniini using the East Asian-Australasian Flyway face the greatest number of non-breeding range threats that were identified.
  • The greatest threat, particularly in the East Asian-Australasian Flyway, appears to be the large-scale development of key passage and non-breeding sites in coastal zones.

Quite why population declines are so common and severe in the Numeniini group is not yet clear but their large body size, low breeding rate and a consequent reliance on high annual survival rates may make them particularly vulnerable to changes in land use and habitat availability across their migratory ranges. The authors hope that this publication will provide a platform for the necessary research and monitoring, to identify and address specific threats, and that continued international collaboration will help this process.

Least Concern? Not really?

The phrase ‘Least Concern’ may be misleading. Although half of the species covered in this review (6 out of 13) are still classified by IUCN/BirdLife as being of ‘Least Concern’ there are important caveats for these species within the COP11 report. Bar-tailed Godwit was classified as ‘Least Concern’ until a few months ago, when a major, sudden drop in adult survival for two populations (menzbieri & baueri) using the East-Asian Australian Flyway was reported. The current list of ‘Least Concern’ species is:

Upland Sandpiper – Declining nesting success is being recorded.

Whimbrel – Up to nine subspecies have been described, four of which are declining in number. Demographic trends are completely unknown for five subspecies.

steppe-w

Little Curlew – Population is only 180,000 and numbers may be declining.

Long-billed Curlew – Numbers appear to be stable (only 160,000) but there have been previous extinctions in 7 US states and large parts of Canada. New climate change predictions suggest major threat to breeding population.

marbled

Satellite-tracking is being used to establish migration routes and stop-over areas for several members of the Numeniini. This is a Marbled Godwit.

Marbled Godwit – Only an estimated 174,000 individuals remain. Two of the three breeding populations are made up of only 2,000 individuals each.

Hudsonian Godwit – Only an estimated 77,000 remain, with a decline in the major Canadian population, where there has been reduced nesting & fledging success.

These caveats suggest that none of the 13 species of Numeniini can be considered to be safe. The fact that the threats to the six species of ‘Least Concern’ are the same ones that have driven the other seven species further up the ‘endangered’ scale – and even to extinction – is extremely worrying.

You can read the full paper here:

A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds. James W Pearce-Higgins et al. Bird Conservation International. ISSN 0959-2709


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

Bar-tailed Godwits: migration & survival

Putting the flags out –  to learn more about one of the most amazing species of migrating wader.

Ruth banner

When we caught 505 Bar-tailed Godwits on the Wash, on the east coast of England, on 29 August 1976 we thought that we would add hugely to our knowledge of the species’ migration but we were disappointed. In the last six years, by adding leg-flags to just 248 birds, the Wash Wader Ringing Group has learnt a lot more.

Forty years ago

On 29 August 1976, in the days of stubble-burning, we had covered four cannon nets with fine, black burnt chaff to hide them almost completely. We knew that the big tide would push birds off the saltings and over the sea wall, there were decoys to pull the birds into the right 1% of a vast, flat field and the weather was good. Everything was ready. I was in a one-man, cabbage-crate hide, in line with my set of two nets. I remember seeing one Redshank look at the decoys and descend, pulling down a vast cloud of over 2000 Bar-tailed Godwits. There were some concerns about birds being too close to one of the nets on my line so we fired three nets, catching 505 bar-tailed godwits and 44 other waders.

Cathy ad and juv

Juvenile with moulting adult

A catch of 505 Bar-tailed Godwits seemed like a game-changer, including 22 that were already wearing rings. 483 new birds were bound to make a huge difference to our understanding of the species’ migration patterns and survival probabilities … surely? Up until that day, the Wash Wader Ringing Group (WWRG) had ringed a total of 1136 Bar-tailed Godwits so we were adding over 40% to the total, using harder rings with a much longer life-expectancy than those added as early as 1959.

This was a moulting flock; an autumn drop in numbers and a previous recovery of a bird in Spain suggested that many birds would spend the winter elsewhere but where? As luck would have it, only one of the birds from August 1976 has ever been found abroad – a bird shot in France in February 1985. The only British recoveries have been a bird found dead in Yorkshire in November 1976 and seven birds found around the Wash between 1979 and 1999. As to subsequent recaptures, 38 birds have been caught again by the WWRG, five of which were retrapped for a third time. With all the best models in the world, these figures are not enough to give a reasonable estimate of survival and there is no way that a change in survival rate could be picked up.

It’s pleasing to report that one bird was still alive on 21 February 2003 – over 28 years after ringing – but even this is not the longevity record for a BTO Bar-tailed Godwit. That’s held by another WWRG bird that was ringed on 22 August 1974 and last recaptured on 4 August 2008 – nearly 34 years later. Perhaps one of the 1976 birds is still alive and waiting to be caught again?

Bar-tailed Godwit migration

Since the 1976 catch, WWRG has been a bit more fortunate in its foreign recoveries of metal-ringed Bar-tailed Godwit, with 2 recoveries in Mauritania, one in Guinea Bissau and another on a ship off Guinea, out of a total of 12 BTO-ringed birds found in Africa. A bird caught in Teesmouth on 13 October 1982 was in Western Sahara five days later, which may give an indication of the timing of post-moult movement. The map alongside shows the full set of BTO recoveries (purple) and foreign-ringed birds found in Britain & Ireland (orange). The dots show the westward post-breeding movement from Russia to the Atlantic coast of Europe and the onward migration of thousands of birds to Africa.

One of the fascinating things about migration is the way that different populations of the same species have developed radically different migration patterns since the last Ice Age, the global maximum extent of which was reached only 20,000 years ago. At the same time that the Bar-tailed Godwits we see in Western Europe are making relatively modest journeys west and south in late summer, some of those of the baueri subspecies are undertaking nine-day, non-stop flights from Alaska to New Zealand. The physiological processes and navigational techniques that birds on the Pacific flyway have mastered would amaze their European cousins. To read more about flyway evolution for Arctic waders, and Knot on particular, see a Review by Theunis Piersema (Journal of Ornithology, 2011).

Conservation Status

Bar-tailed Godwits are classified as near-threatened by BirdLife International and the IUCN. There are four recognised subspecies facing various threats, as shown in the species fact-sheet here. 

Sam winter gloves

Bar-tailed Godwits wintering on the Wash are of the lapponica subspecies

Two subspecies visit the Wash Special Protection Area (SPA); lapponica from Norway through to western Siberia and taymyrensis from central Siberia. Two subspecies, menzbieri and baueri, use the East Asian-Australasian Flyway and are both undergoing extremely rapid declines, in large part due to severe habitat loss in the Yellow Sea. As a result of severe problems for waders using this flyway, the species has been uplisted to Near Threatened (BIrdLife International).

Satellite-tagging has revealed the impressive trans-oceanic migration routes of individuals between Alaska and New Zealand and shown the importance of the Yellow Sea for birds as they return north in the spring. Colour-rings and flags have shown that there has been a sudden drop in survival rates for Bar-tailed Godwits and other species using sites in China and other rapidly developing countries of South-East Asia, leading to urgent calls for conservation initiatives at an international scale. You can read more about this emerging story in these three papers.

Picture1

Learn more about the amazing migration of Bar-tailed Godwits on the New Zealand Science Learning Hub

Contrasting extreme long-distance migration patterns in bar-tailed godwit Limosa lapponica. Phil Battley et al. Journal of Avian Biology. 10.1111/j.1600-048X.2011.05473.x 

Simultaneous declines in summer survival of three shorebird species signals a flyway at risk. Theunis Piersma at al. Journal of Animal Ecology. 10.1111/1365-2664.12582

Declining adult survival of New Zealand Bar-tailed Godwits during 2005–2012 despite apparent population stability. Jesse Conklin et al. Emu. http://dx.doi.org/10.1071/MU15058

For Bar-tailed Godwits wintering in western Europe there is currently less immediate conservation concern, although there are warming conditions in their breeding grounds and over-fishing and emerging diseases of shellfish are known to be affecting estuaries on both sides of the North Sea. Things are more worrying in West Africa, where numbers have declined from 746,000 to 498,000 over a period of 30 years, according to a report by van Roomen et al. Some of these birds spend time in the Wash in the autumn on their way south.

Status of coastal waterbird populations in the East Atlantic Flyway. With special attention to flyway populations making use of the Wadden Sea. van Roomen et al.

Flying the flag

Cathy gluing

Each bird wears a two-letter flag and a white colour-ring (shown here)

Given the worsening conservation status of Bar-tailed Godwits and the gaps in our understanding of what is happening to birds that visit the Wash SPA, the WWRG decided that it would help if birds could be monitored through colour-ringing. That way, the movement and survival of individuals can be monitored using a telescope instead of relying on recapture.

The flagging of Bar-tailed Godwits on the Wash has dramatically increased the number of records of birds subsequent to ringing but the scheme is still in its early days. Flagging started in August 2010 but the first significant catch did not take place until 11 February 2012, when 56 birds was flagged. According to Phil Atkinson, who runs the WWRG database for the species, one third of the birds from this catch have been resighted alive in the four years since that catch (compared to 1% recapture rate for metal-ringed birds in the four years after the 1976 catch).

Cathy KAMost resightings have been on the Wash and those from elsewhere have tended to confirm what was known from metal ringing. A moulting bird on the Wash was seen on the Wirral (northwest England) in the same autumn, showing that birds moulting on the Wash can move elsewhere in Northwest Europe to winter. A non-moulting bird, caught at Terrington on 30 September 2011, was resighted at Ebel Khaznaya, Mauritania 50 days later. These two resightings confirmed that the Wash is an important site not only for the wintering Fenno-Scandinavian and western Siberian lapponica breeding populations but also central Siberian taymyrensis birds, that pass through in autumn to wintering areas in West Africa. The majority of overseas records have come from the Wadden Sea in spring and autumn, when birds have been on return passage to the breeding areas. There’s a 1996 summary of migratory movements of metal-ringed WWRG birds here:

The origins, moult, movements and changes in numbers of Bar-tailed Godwits Limosa lapponica on the Wash, England, Bird Study.  http://dx.doi.org/10.1080/00063659609460996 

Aivar Estonia

UV was spotted in Estonia in August 2012

By the end of 2015, 248 Bar-tailed Godwits had been colour-ringed and 92 of them seen again, many locally on the Wash. These high resighting rates are a consequence of focused searches by WWRG members and reports from birdwatchers submitting their records to sightings@wwrg.org.uk. Over the next few years it will be possible to estimate annual survival probabilities and to monitor how these change in the medium to long term. As was shown in the Yellow Sea, spotting a dramatic drop in colour-ring return rates provides evidence that development pressures are having an impact upon migratory species. Worsening conditions in the breeding grounds or wintering areas could well be detected through a more gradual but no less serious reduction in survival rates.


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