England’s Black-tailed Godwits

Back in 1976, all of the UK’s fifty pairs of Black-tailed Godwits were breeding in the Ouse Washes, which cut across the Norfolk/Cambridgeshire border in eastern England. Over the next thirty years, Ouse Washes numbers collapsed and the Nene Washes (near Peterborough) became home to forty or more pairs. What demographic processes were at play that led to this 24 km shift in the population centre and are there lessons to be learnt about the future conservation of England’s limosa Black-tailed Godwits?

43 years of breeding Black-tailed Godwits

The Washes of England represent a westerly extension of the breeding range of limosa Black-tailed Godwits, the focus of which is the Netherlands. This is a subspecies that’s in serious trouble; there has been a 75% decline in the Dutch population, as you can read here. The RSPB has invested in the conservation of Black-tailed Godwits for over forty years, most recently as part of Project Godwit, a partnership with WWT. In a 2021 paper in Wader Study, Mo Verhoeven and colleagues compare detailed studies in the period between 1999 and 2003 with more recent work (2015-2019) to try to understand how changes in demographic rates (productivity, survival and recruitment) have impacted upon the number of breeding pairs.

This study focuses on Black-tailed Godwits on the Low Wash, an area of the Nene Washes that is managed by RSPB. After periods of high rainfall, these areas are flooded to store excess water, mainly in the winter months. Fieldwork during the two periods of intense monitoring (1999-2003 & 2015-2019) included:

  • Searches for marked birds, when they return in March and April and throughout the breeding season.
  • Locating nests in April and then following breeding attempts (measuring and weighing eggs, to back-calculate to lay-dates, and monitoring nesting success).
  • Ringing and colour-marking chicks.
  • Nest data loggers and cameras were used in the later period (2015-2019), to help establish timing of predation events.
  • Adults were trapped on the nest (2015-2019), to add rings, colour-marks and, in some cases, geolocators.

The switch to The Nene  

Back in 1975, all of the limosa Black-tailed Godwits nesting in the UK were to be found in the Ouse Washes. The graph below shows the number of pairs nesting in the Ouse and Nene Washes, together with other regions of England. The two study periods (1999-2003 & 2015-2019) are highlighted. In 1999, at the start of the first period of intensive study, over half of pairs were in the Nene Washes, with a rapid increase in this proportion by 2003. The situation remained relatively stable through to the start of the second period of intensive study in 2015.

The graph showing the number of breeding pairs only runs through until 2017, as the number of breeding pairs in 2018 and more recent years has been affected by head-starting, the process of hatching chicks in incubators and raising them in captivity, through to fledging. The WaderTales blog Special Black-tailed Godwits describes the excitement and anticipation as the first 25 captive-reared chicks were released at the Ouse Washes. The first head-started birds returned in 2018.

Black-tailed Godwit chick being raised in captivity

In 1992, following multiple years of spring flooding at the Ouse Washes, the godwit population in the UK declined to only 19 pairs. There was a steady increase of godwits at the nearby Nene Washes and the UK population recovered to 53 pairs by 2006. Since then, the breeding population at the Nene Washes had been slowly declining until head-starting provided a welcome boost. See Head-starting Success and reports on the Project Godwit website.

Comparing the two periods

The early period of intensive work in the Nene Washes (1999-2003) took place when the population was increasing strongly, a trend that continued until 2006. The later period (2015-2019) coincided with a shallow decline. For conservationists, keen to maintain a UK population of breeding Black-tailed Godwits, it is important to understand the causes of the differences in population trends, if the right conservation solutions are to be deployed to resolve ongoing problems for this red-listed wader.

Adult survival: Large waders, such as Black-tailed Godwits, are long-lived birds (see Measuring Shorebird Survival) and it is unsurprising that the annual survival rate of Black-tailed Godwits nesting in the Nene Washes was found to be high, with an estimate of 88%. The short period of time available between ringing and potential observations for birds that were marked in the second period (2015-2019) meant that there were fewer sightings from which to calculate survival rates of birds from this recent period. Despite this smaller sample, the research team are confident that adult survival has not declined over time and is therefore not the cause of the change in population trend between the two periods.

This chick weighs 30.6 grammes (just over an ounce)

Nest Survival: The number of nests lost to flooding was very low indeed; none in the earlier period and only 1% in the later. Nest desertion rates were higher in the more recent period (7%) than during 1999-2003 (2%) but the differences are not statistically significant. The big change is in predation rates. Only 22% of the nests that failed in the period 1999-2003 failed due to predation but this more than doubled in 2015-2019. Analyses that took account of lay-date showed that the chance of hatching was much lower in 2015-2019 than in 1999-2003, irrespective of the timing of nesting attempts.

Chick survival: Given the increased predation of nests, it is perhaps unsurprising that the chick survival rates were also lower in 2015-2019 than in 1999-2003. Modelling suggests that a Black-tailed Godwit chick that hatched in one of the summers between 1999 and 2003 was between 2.4 and 3.6 times as likely to survive the first fourteen days of life as a chick that hatched between 2015 and 2019.

Explaining the patterns

The Ouse and Nene Washes are only 24 km apart but adults are highly site-faithful, and it is therefore likely that birds will try to nest in the same place in consecutive years, if at all possible. The Ouse Washes population was not marked at the time of the flooding events in the springs of the 1990s, so we do not know whether the growth in numbers on the Nene during this period was linked to flood-related declines on the Ouse. However, we do know that, when water levels are too high at either the Ouse or the Nene Washes, pairs will nest on nearby arable fields, just outside the flood plain. Nests on arable fields at the Nene have never resulted in successful fledging, so any such attempts near the Ouse in the 1990s may well have gone unnoticed.

As discussed in Site fidelity in Black-tailed Godwits, chicks are also highly philopatric (tending to return to the site from which they fledged). Of the 63 chicks raised on the Nene Washes, for which subsequent breeding locations have been ascertained, 61 have been found breeding in their natal area. This is the same pattern as found in the Dutch breeding areas. It is likely that the growth in numbers in the Nene Washes in the period 1977 to 2006 was driven by high productivity and subsequent local recruitment. The key question is therefore ‘why has breeding success declined since this time?’

Ringing a Black-tailed Godwit chick

Some causes of reduced breeding success can be ruled out. None of the 213 nests was trampled by grazing cattle (see Big Foot and the Redshank nest) and only one nest was flooded. This leaves predation as the main cause of low success. The authors suggest three things that might have changed:

Lower numbers of other waders: Over half of the other waders nesting in the Nene Washes study area disappeared between 2000 and 2016, with losses of 73% of breeding Lapwing, 46% of Redshank and 49% of Snipe. The number of Black-tailed Godwit nests increased during this period. These four species all work together to raise the alarm if a predator is present and to mob mammalian predators such as fox and stoat. Reduced overall wader numbers could have reduced predator deterrence and will certainly have meant that there were fewer nests of other waders for predators to find.

Predated Black-tailed Godwit nest

Reduction in non-wader prey: The number of Pheasants in the area surrounding the Nene Washes is thought to have decreased, with reductions in the numbers released for shooting. Fewer pheasants around during the breeding season may result in a reduction in the availability of Pheasant eggs, sitting females and chicks. The lack of this food could have increased predator pressure on breeding waders.

Broader suite of predators: Badgers, Common Buzzards and Red Kites have colonised the area and Marsh Harrier numbers have increased. Badgers are known to target ground-nesting birds and avian predators take eggs, chicks and occasional adults.

What to do next?

Head-started chicks in the Project Godwit release cage

The head-starting project has been designed to give a short-term boost to numbers of breeding Black-tailed Godwits on the Ouse and Nene Washes. In the longer term, Project Godwit aims to improve habitat management in ways that can lead to increased productivity, without head-starting. The authors identify several actions to try to increase productivity, which include:

  • Maintain the openness of the wader nesting area, by removing trees, reed beds and rushes, in which predators can perch, nest and hide (there’s more about this in Mastering Lapwing conservation).
  • Attempt to increase the abundance of alternative prey (small mammals) in the surrounding landscape (see Can habitat management rescue Lapwing populations?).
  • Provide diversionary food for key avian predators (see Deterring birds of prey).
  • Use a mixture of fences and predator control (see Toolkit for wader conservation).
  • Flood the grassland in the winter period, to reduce numbers of small mustelids (stoats and weasels) in the godwit nesting areas and concentrate small mammal prey (e.g. mice and voles) on the edges of the Nene Washes.

Some additional thoughts (not in the paper)

The growth in the Nene Washes population of Black-tailed Godwit between 1977 and 2006 suggests that Black-tailed Godwits can do well in the right circumstances. Perhaps there are other areas of lowland wet grassland – especially ones with low predator densities or effective predator management – in which head-started individuals might thrive?

Having a muddy time in Portugal

An annual survival rate of 88% means that only about one in eight adults dies in a given year. If survival rates change then that can have a major effect on the viability of a small population. The reliance of limosa Black-tailed Godwits upon a limited number of habitats and key sites in the non-breeding season, especially in Portugal, Spain and Senegal, make them very vulnerable to changes, whether brought about by climate, new farming systems (especially rice growing) or habitat removal (see blog about planned airport in Tagus estuary. The conservation of limosa Black-tailed Godwits is a flyway-scale challenge, as outlined in this action plan, produced by AEWA.

Read more

Diagnosing the recent population decline of Black-tailed Godwits in the United Kingdom. Mo A. Verhoeven, Jennifer Smart, Charlie Kitchin, Sabine Schmit, Mark Whiffin, Malcolm Burgess  and Norman Ratcliffe. Wader Study.

This study was jointly funded by the RSPB and Natural England through the Action for Birds in England Partnership and through an EU LIFE Nature Programme project (LIFE15 NAT/UK/00753 – LIFE Blackwit UK) in partnership with the Wildfowl & Wetlands Trust with support from the National Lottery Heritage Fund via the Back from the Brink Programme.


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

Following Sociable Lapwings

Understanding the migration routes of threatened migratory species is key to supporting declining populations.

Targeted help for the critically endangered Sociable Lapwing has come another step closer, thanks to the publication of a paper by Paul Donald and colleagues in the Journal of Ornithology.  In it, they describe how satellite tracking, colour-ringing, studies of historical records and flock counts have combined to give a much clearer picture of the main sites used by Sociable Lapwings during migration and in the winter. In addition, the research team’s work has produced a more robust estimate of the world population of the species. Given the threats that Sociable Lapwings face when they are away from their breeding sites – particularly from hunting – this is all crucial information for their conservation.

The Sociable Lapwing

Nesting close to a village

Sociable Lapwings once bred from Ukraine through to western China. There still may be a small population in southern Russia but the breeding range is now almost entirely restricted to the steppes of central and northern Kazakhstan (Sheldon et al 2012). For centuries, Sociable Lapwings have relied upon grazing by herds of Saiga Antelopes, which created open areas in which to nest. As natural grazing systems have broken down, Sociable Lapwings have become increasingly restricted to grazed land around villages (Kamp et al. 2009). Given that current productivity levels appear sufficient to maintain this small population in a viable state, low adult survival is thought to be the most likely driver of recent population declines (Sheldon et al. 2013).

Prior to this study, little was known about the wintering areas used by Sociable Lapwings. There had been some reports of flocks in eastern Africa but most information from countries such as Sudan was several decades out of date. Further east, sightings in Pakistan and India accounted for only small numbers of the known population. Did birds travel straight from breeding areas to winter sites or were there key stop-over sites that were missing from the map? Did birds in the western part of the breeding range head southwest to East Africa, with those in the east heading south to Pakistan and India? It was time to track some birds!

Distribution map from BirdLife International data zone

Detective work

Colour-ringed individual

Paul Donald and colleagues undertook a long-term study of the movements of Sociable Lapwings, using satellite tagging, colour-ringing, targeted field surveys and a database of historical and recent sightings. The collation of this database involved a huge amount of painstaking work, with researchers checking museum collections, searching through unpublished literature, liaising with local birdwatching organisations and looking for bird lists and images, via the Internet.

Studies of breeding birds were mainly focused upon an area around Korgalzhyn, in central Kazakhstan where, between 2004 and 2015, 150 adult Sociable Lapwings and 1473 chicks were colour-ringed. The main aim was to estimate survival rates but some of these marked individuals provided valuable data when seen during visits to potential wintering and passage sites. Most of this fieldwork outside of the breeding season was undertaken by local conservationists and ornithologists, with their efforts being coordinated by the BirdLife International Social Lapwing Project.

Releasing a satellite-tagged bird

Detailed information on movement patterns was collected with the assistance of 29 satellite-tracked adult birds, caught in the breeding grounds between 2007 and 2015. Most were tagged near Korgalzhyn, in central Kazakhstan but five were tagged in an area about 800 km further east. Of these 29 birds, 21 were female. Technical developments by Microwave Telemetry Inc. meant that early 9 g solar-powered tags could be replaced by 5 g tags in later years.

Tracked birds

The paper by Donald et al contains detailed information about the movements of individual birds and how they were tracked. Anyone contemplating a similar study may want to read about how data were filtered and ‘clusters’ and ‘transit points’ were defined.

Early (larger) tags did not produce as much information as later (smaller) tags. The fact that one of the early-tagged birds was seen back on the breeding grounds without its harness and tag suggests that harness failures may have been an issue early on. 16 of the 29 tags provided data that enabled the research team to plot 27 complete autumn migration journeys and 13 complete spring journeys. Some birds were tracked for longer periods, producing data for two or more autumn (7 birds) and spring (3 birds) migrations. Birds followed for more than one year repeated almost exactly the same autumn and spring journeys.

Note the short vegetation

The tracked birds set off on one of two routes at the end of the breeding season, either heading west and south to northeast Africa and the Arabian Peninsula (the western route) or due south to Pakistan and India (the eastern route):

  • Seventeen birds used the longer western route, west across Kazakhstan, across or around the western Caspian Sea, then south through the Caucasus and the Levant, before reaching wintering areas in Saudi Arabia and eastern Sudan (map below).
  • Seven birds set off on the shorter eastern route, due south to Turkmenistan and Uzbekistan, then over or around the mountains of northern Afghanistan to wintering areas in Pakistan and north-western India.
  • Migration direction was ascertained for 22 birds from the central Kazakhstan group: 16 birds took the westerly route and 6 used the eastern route. Only two of the birds that were marked further east produced usable tracks, with one bird following the eastern route and one following the western route.
  • Birds using the eastern route travelled an average of 2839 km, with birds on the western route travelling 5199 km – nearly twice as far. Birds on both flyways departed their breeding grounds and arrived on their wintering ground at around the same time. Key stop-over areas were identified (see paper).
This tagged bird was photographed in a flock in Pakistan
  • In autumn, birds on the eastern route stopped only once, at Tallymarzhan (on the border of Turkmenistan and Uzbekistan), remaining in the area for between 29 and 48 days. Western birds stopped more often and generally for much shorter periods.
  • Central Azerbaijan and northern Afghanistan seem to be important spring staging sites for birds on the western and eastern routes, respectively, but these sites have yet to be surveyed.
  • The timing, direction and use of stopover areas of birds tracked in more than one year were highly consistent but there was much variation between individuals.

Only eight of the Sociable Lapwings colour-ringed as chicks on the breeding grounds in central Kazakhstan were subsequently seen outside Kazakhstan: five at the Kuma-Manych Depression in Stavropol (on the western route) and three at Tallymarzhan in Uzbekistan (eastern).

Three recently-fledged youngsters

Chicks and adults gather in mixed flocks prior to migration and it is thought that they migrate together. Perhaps circumstances and the adult birds with which young birds happen to associate determine the direction of the first migration south. If it is still alive, why should a young bird migrate in a different direction in a subsequent year?

Adults used up to three different areas during the course of a winter and, as far as could be determined from the small number of multi-year tracks, did the same thing in subsequent years. An analysis of the sites used by wintering birds emphasised the importance of arable habitats – most stopover sites are in areas that have been under cultivation for over 2000 years.

There was little evidence of strong breeding site fidelity, with adult birds moving up to 300 km from the site of tagging in the next year. For a species that may need to search for nesting sites in recently-grazed or burnt-off grassland, within a relatively homogeneous steppe habitat, it is perhaps unsurprising that there appears to be less of a tendency for birds to be site-faithful than seen in many other species of wader.

Finding the flocks

The research team found that their database of historical and recent records of flocks of migrating and wintering Sociable Lapwing identified the same two major migration routes that appeared from traces of tracked birds. There is a strong suggestion that there is a third, central route that takes birds to Oman, parts of eastern Saudi Arabia and to sites around the Persian Gulf and the Gulf of Oman. None of the 29 tagged birds happened to end up in these areas.

Counts on both sides of the border between Uzbekistan-Turkmenistan, in the autumn of 2015, suggested that between 6000 and 8000 Sociable Lapwings may use this area when migrating along the eastern route. Using information on the proportion of tagged birds that visited this area, and for how long, the research team estimate that the global population of Sociable Lapwings is about 24,000 individuals, although the 95% confidence interval is broad (13,700 to 55,560 birds).  The estimate is the most robust so far and the methodology can be repeated in the future, in order to monitor population change.

The bigger picture

In Palaearctic species with intercontinental flyways to both Africa and Asia, individuals breeding in the western part of the range usually take the western flyway and those in the eastern part of the breeding range migrate along an eastern flyway, with a clear migratory divide within the breeding range. This is the case for species as diverse as waders, bustards and bee-eaters. Discovering that Sociable Lapwings are not so similarly constrained was a surprise, with the route used being independent of the longitude of the tagging site.

Post-breeding moulting flock in central Kazakhstan

During migration and on the wintering grounds, Sociable Lapwings are strongly associated with areas of agriculture, particularly along rivers. Only in northern Syria and and Tallymarzhan were birds found in more natural steppe grasslands. Birds are now using irrigated areas of the Arabian Peninsula, where agricultural land has been created in former deserts. It appears that new generations of Sociable Lapwings, taking advantage of these novel opportunities, now undertake shorter migratory journeys and have perhaps established new pathways. This form of Generational Change is the subject of a WaderTales blog about Black-tailed Godwits.

Sociable Lapwings are widely dispersed over huge and often inaccessible areas on both the breeding and wintering grounds. Their concentration in a small number of predictable staging areas, during migration, offers the best opportunity to gather information on population trends. Birds using the western route appear to have more available options than birds in the east, making numbers harder to monitor.

Birds using the western route, particularly in Syria and Iraq, are targeted by hunters in the autumn and there is no protection for any of the stopover sites identified in this study. The authors suggest that it is particularly important to know more about spring staging areas in Azerbaijan, as this is a focal area for returning birds using the western route and potentially an area in which hunting takes a significant toll. Birds using the eastern route appear not to be hunted – or at least not in the same sort of numbers as in the west. Sociable Lapwings that use the less well-understood central route and that winter in the Arabian Peninsula may be vulnerable, as they share irrigated fields with species that are popular with hunters.

To learn more

The authors, and everyone else who has contributed to decades of Sociable Lapwing research, are to be commended for the work they have done. Now that key sites have been identified, it is to be hoped that there is political will to provide protection for this critically endangered species. Actions will need to include site designation, local involvement in conservation action and concerted efforts to curb illegal hunting.

Part of a flock of pre-migratory birds in central Kazakhstan (409 birds were counted)

The paper upon which this blog is based is:

Migration strategy, site fidelity and population size of the globally threatened Sociable Lapwing Paul F. Donald, Johannes Kamp,Rhys E. Green, Ruslan Urazaliyev, Maxim Koshkin & Robert D. Sheldon. Journal of Ornithology.

Other WaderTales blogs about tracking projects that help to identify migratory hot-spots used by threatened waders include:

Spoon-billed Sandpipers: Track and Trace (finding wintering and passage sites)

Black-tailed Godwits are on their way home (Tagus Estuary airport plan)

Teenage Waders (Hudsonian Godwits in the Pampa wetlands of Argentina)


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

WaderTales blogs in 2020

Around the world in sixteen blogs

2020 was a strange year, as covid swept around the world and more and more of us faced travel bans. Throughout it all, waders/shorebirds continued to fly thousands of kilometres in spring and autumn.

Five out of sixteen of the year’s WaderTales blogs focused on international migration studies, using a mixture of colour-rings, geolocators and satellite tags. It was particularly interesting to think more about ‘teenage’ waders – the period between fledging and first breeding. It may be a couple of years or more before shorebirds return to their breeding grounds; what do we know about what happens during this period? Are vulnerable and threatened species and the sites that they rely on receiving enough conservation support during these important, teenage years?

  • Teenage waders is ostensibly about Hudsonian Godwits that spend the non-breeding season in Chile and breed in Alaska. Juan Navedo & Jorge Ruiz noticed that a small number of satellite-tagged birds headed for Argentina instead of Alaska in April. This led to the discovery of flocks of young Hudsonian Godwits (and adults that choose not to breed in a particular year) in the pampa wetlands – areas that are under threat from industrial-scale farming.
  • Spoon-billed Sandpipers: track & trace follows tagged Spoon-billed Sandpipers, as they travel from their breeding sites in Russia, through China and beyond. This is an amazing story; thirteen birds carrying back-mounted transmitters have revealed information that will enable the targeting of conservation measures to support a global population that is estimated to be just 660 birds.
  • Gap year for sandpipers is based upon a Peruvian Semipalmated Sandpiper paper that investigates the survival advantage of not migrating north to breed in any particular year. It reveals that taking a gap year may be a sensible strategy in some circumstances.
  • Which Icelandic Oystercatchers cross the Atlantic? Around 30% of Oystercatchers remain in Iceland for the winter, with the rest of the population flying south across the Atlantic in autumn. Having made an initial ‘decision’ to be a resident or a migrant, an individual sticks to this strategy but what determines whether a particular Oystercatcher becomes a migrant?
  • A Rhapsody of Whimbrel asks whether Whimbrel use time and weather cues in their travel ‘planning’ and whether their plans change during the course of their lives. By looking at weather patterns encountered by tagged birds, flying between western Africa and Iceland, Camilo Carneiro shows that old birds may be able to learn new tricks.

A Scottish trio

2020 seems to be the year of the Scottish WaderTales blog, with three spring/summer stories about research led by RSPB Scotland staff.

  • Migration of Scottish Greenshank summarises a study of a small number of breeding birds, using a mixture of colour-ring sightings and geolocator records. Unlike their cousins, that breed in eastern Russia and migrate to Australia or even New Zealand, Greenshank nesting in northern Scotland are short -distance migrants, mostly staying within Britain & Ireland for the whole of their lives
  • Trees, predators and breeding waders is all about how the presence of woodland affects the distribution of mammalian predators, even after the trees have gone. Species such as Curlew and Dunlin are benefiting from the removal of forestry plantations from the peat blogs of Forsinard, in north-east Scotland. We discover that it takes a long time for habitat restoration to deliver conservation benefits because of residual levels of predator pressure.
  • Scotland’s Dotterel: still hanging on discusses how climate changes are affecting the distribution and numbers of Scottish Dotterel. High up on the Cairngorm plateau, scientists have been studying the links between Dotterel numbers and climate change. The distribution of nests seems to reflect local weather conditions but declining numbers may be more of an African problem.

Nesting waders

  • Where to nest? Almost all waders/shorebirds nest on the ground which means that nests are vulnerable to predation. Two main strategies have evolved to minimise egg losses, cryptic egg colouration in open settings and hiding nests in vegetation. A study in Iceland investigates which strategy appears to be more successful and in what circumstances. Do Iceland’s open-nesters (Oystercatcher, Golden Plover & Whimbrel) fare as well as nest-hiders (Redshank, Snipe & Black-tailed Godwit)?
  • Curlews and foxes in East Anglia raises some interesting conservation issues. Might it be possible to attract breeding Curlew to patches that can be protected from potential predators? Habitat improvement measures that have been designed to help Stone Curlews are popular with Curlews too. Could shallow soil disturbance be used to support Curlew conservation?

Black-tailed Godwits

WaderTales started out as a way to provide feedback to the volunteers who report colour-ringed Black-tailed Godwits. Most of the twenty blogs about the species refer to islandica but the two in 2020 focus on limosa. The first blog is a follow-up to the 2019 story about a plan to build a new airport within the Tagus Estuary. This threatens to undo much of the good work of Project Godwit – trying to rebuild the English breeding population in the Fens. To raise money for this project, Jen and Mark Smart cycled 1000 km across England, vising many of the sites where head-started Project Godwit chicks have been seen. It was a great opportunity to provide updates on the migration stories of these special birds.

  • Black-tailed Godwits are on their way home reveals the importance of the Tagus Estuary (Portugal) to England’s breeding limosa Black-tailed Godwits.
  • Cycling for waders is about the head-starting initiative to rebuild the English breeding population of Black-tailed Godwit – and a sponsored cycle ride to support Project Godwit & International Wader Study Group.

Behaviour

Two of this year’s blogs are about bird behaviour, other than migration.

  • Disturbed Turnstones focuses upon a paper about the changing distribution of Turnstone in northeast England. As numbers have declined, birds have withdrawn from beaches with more people and dogs. Off-shore roosts seem to have become increasingly important.
  • Flagging up potential problems discusses safety issues associated with using flags and flag-mounted geolocators when studying waders. At the heart of the blog is a study of Common Sandpiper survival and migration but there is additional information about ways to minimise problems that may occur when using leg-flags.

Book reviews

Occasionally, the publication of a new book about waders/shorebirds is used as a hook upon which to hang a WaderTales blog. Two new books, Red Sixty Seven and Flight Lines, were treated in this way in 2020.

  • Nine red-listed UK waders discusses why nine species of wader find themselves on the UK red list of species of conservation concern). The book, which covers all of the 67 species on the UK Red List, is raising money to help fund scientific research by BTO and RSPB.
  • Plovers from the north is a blog about the global migration patterns of Grey Plovers (Black-bellied Plovers). There is an Australian focus but this was a good opportunity to summarise recent research from around the world.

Previous summaries

WaderTales blogs in 2019

WaderTales blogs in 2018

WaderTales blogs in 2017

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.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. There’s a full list of blogs here.

Gap years for sandpipers

Will this Semipalmated Sandpiper fly north to breed?

With the approach of spring in the Northern Hemisphere, waders (shorebirds) that have spent the previous few months on the shores of Africa, the Americas, Asia, Australasia, Europe and oceanic islands need to decide whether to fly north. Those that depart leave behind flocks of young birds, together with adults that ‘choose’ not to migrate north and attempt to breed. In a paper in Movement Ecology, Eveling Tavera and colleagues investigate how the decisions made by individual Semipalmated Sandpipers that spend the non-breeding season in Paracas (Peru) are likely to affect their chances of survival.

Semipalmated Sandpipers

The Semipalmated Sandpiper is one of the smallest of the world’s waders. The species is designated as near-threatened by BirdLife International and IUCN, despite its large breeding range. In their assessment, they draw attention to declining numbers, potentially linked to reduced food supplies in staging areas and to changes to arctic breeding habitat. Hunting pressure in some parts of the wintering range (especially the eastern seaboard of South America and in the Caribbean) may particularly affect Semipalmated Sandpipers that breed in eastern Canada.

Back in the 1970s, when I spent three summers in James Bay (northern Canada), I remember catching skinny juvenile Semipalmated Sandpipers that weighed under 20 g, which is way smaller than a House Sparrow (24.2 g – 30.7 g: BTO BirdFacts). We also caught fat, 40 g  adults that were about to leave and head to countries such as Suriname in South America, perhaps stopping off in the Bay of Fundy on their way south. In just a few months, it would be time to fly north again and I guess we assumed that any bird that was alive would at least try to make the return journey. After all, these are small shorebirds and most small shorebirds breed in their first year.

The distribution of Semipalmated Sandpipers during the non-breeding season covers a broad range of latitudes, from about 25°N (southern Florida) to 23°S (northern Chile and southern Brazil). Some of the birds flying to Arctic Canada, Alaska and Northeast Russia are travelling a lot further than others. A bird setting out on a return journey to northern Quebec from Peru will need to find more resources to fuel its journey than one flying from the Caribbean. The additional fattening requirement could potentially affect the ability of individuals to make the return migration.

Shorebird Survival

Graph from Méndez et al in Ibis

In their global review of annual survival rates of shorebirds, Verónica Méndez and colleagues were able to include 56 species from around the globe. Unsurprisingly, small waders tend not to live as long as larger species. Combining the various studies of Semipalmated Sandpiper, they estimated an annual survival rate for adults of 0.61 (see Measuring shorebird survival). This means that, on average, there’s a 39% chance of an individual dying between one breeding season and the next.

We know that waders don’t always breed every year, as discussed in Teenage Waders. Small waders have lower life expectancy than large waders (Waders are long-lived birds) so missing out on a breeding season makes much more of a difference to a small sandpiper than to a Knot (estimated survival rate 0.8 or 20% chance of dying within the next twelve months) or an Oystercatcher (0.89; 11%).

As Tavera et al point out in the introduction to their paper, although most small shorebirds attempt to breed in their first year of life they may have lower breeding success than older individuals. In Semipalmated Sandpipers, young birds start nesting later in the spring, lay smaller and fewer eggs, and produce fewer chicks (references in paper). When comparing potential reproductive output, a bird that does not migrate north in its first year is probably missing out less than an adult that ‘takes a year off’.

Breeding habitat in Alaska – a long way from Peru

Semipalmated Sandpipers in Peru

The results presented in the Tavera et al Movement Ecology paper come from a long-term Semipalmated Sandpiper colour-ringing study in the Paracas National Reserve, 250 km south of Lima, in Peru. Over a period of five years, 1963 birds were caught in mist nets and individually marked, producing 3229 resightings. Only eight of the marked birds has been seen during the nesting season, all in Alaska and western Canada. This paper builds on a previous paper: Effects of migration distance on life history strategies of Western and Semipalmated sandpipers in Perú.

The key findings in the study are:

  • 28% of first-year Semipalmated Sandpipers remain at Paracas, instead of heading north
  • 19% of adults remain in Paracas instead of migrating.
  • The apparent annual survival rate of first-years that head north is 0.555, compared to 0.671 for first-years that stay at Paracas.
  • For adults, apparent annual survival rate of those that migrate is 0.614, compared to 0.808 for those that stay.

The fact that 28% of youngsters in this particular population of Semipalmated Sandpipers don’t migrate north in the first year was unexpected, given what had been learnt from previous studies of the species, but the fact that one in five adults ‘choose’ not to breed in any year is probably more surprising. In a species with a declining population, these missed opportunities to boost the population appear concerning.

Short and long bills

Measuring bill length

Several thousand Semipalmated Sandpipers spend the non-breeding period at Paracas, including individuals with long bills (which are thought to fly there from eastern Arctic breeding populations, about 8,000 km away) and short bills (likely from western Arctic breeding populations, up to 11,000 km distant). There is more about these morphometric differences in this paper by Cheri Gratto-Trevor et al in Waterbirds.

It is not possible to assign individual Semipalmated Sandpipers to a particular population, especially as there are also sex-based differences in bill length, and gender could not be determined in the hand. However, there is a trend for longer-billed birds to be from the east. The eight colour-marked birds from Paracas that have been seen in the western part of the breeding range were all short-billed or intermediate-billed birds.

  • Larger-billed juveniles appear more likely to migrate than smaller-billed juveniles, suggesting that Semipalmated Sandpipers that have travelled less far are more likely to breed in the first year.
  • Resightings of flagged birds suggest that the survival of first-year birds that fly to the Arctic in their first spring is markedly lower in small-billed birds than in long-billed birds.

The cost of migration seems particularly high in small-billed, first-year Semipalmated Sandpipers. These birds tend to be longer-distance migrants, from the western end of the breeding range.

Modelling the costs and advantages of migration

Eveling Tavera and her colleagues have found that survival is higher for Semipalmated Sandpipers that stay in Paracas than for migrants. During the period April to September, the apparent survival rate for first-year birds and adult birds is much higher for birds that do not migrate.  The survival advantage acquired by non-migrants is significantly greater for adults (0.215) than for yearlings (0.140).

Clutch of Semipalmated Sandpiper eggs

By failing to migrate, individual Semipalmated Sandpipers miss out on a breeding opportunity. Does a bird that lives longer but does not breed in every potential year produce more youngsters than a bird that lives a little less long but breeds every year? In an appendix to the paper, the research team calculate whether the survival advantage for birds that stay in Paracas is high enough, in fitness terms, to compensate for the loss of potential youngsters. They used values for annual survival, mean clutch size and hatching success from studies by Weisser et al and Gratto et al, for adults and first-year birds, to produce figures for Lifetime Reproductive Success (LRS). The predicted survival advantage of non-migrating adults (0.240) is higher than that of first-years (0.134) because they forego a larger average potential reproductive output than do inexperienced birds.

Using these calculations:

Teamwork: birds are mist-netted at night
  • On average, a first-year migrant will have the same LRS as a bird that does not migrate if its survival in the first year is no more than 0.134 lower. This is close to the measured value of 0.140 for the Paracas birds.
  • On average, an adult migrant will have the same LRS as a bird that does not migrate if its survival in that year of life is no more than 0.240 lower. This is close to the measured value of 0.215 for the Paracas birds.

Based on the modelling of LRS and survival rates, the team conclude that ‘juvenile and adult birds staying at Paracas compensate for the loss of a breeding opportunity with higher survivorship than migrant birds’.

Different non-breeding populations

Tiny bill of an Alaskan Semipalmated Sandpiper

The Semipalmated Sandpipers that breed across North America and the far eastern tip of Russia travel to a wide range of destinations in the autumn, with birds mixing in the non-breeding season. The Paracas site is a long way from the species’ breeding grounds and the results may suggest that migration is constrained by distance. However, there could be other processes at play, especially if food supplies are limited at the time when individuals need to fatten up for migration. Jeroen Reneerkens et al showed that Greenlandic Sanderling that spend the winter near the equator (Mauritania & Ghana) had lower apparent survival rates than birds that travelled much further south (Pretoria). They were also less likely to breed in their first year than birds spending the breeding season in other locations, and arrived on their breeding territories late in the season. Migration distance is not always a problem, it transpires, as long as there are refuelling possibilities on the way north, as described in Travel advice for Sanderling. This is also discussed in Overtaking on Migration, a Black-tailed Godwit blog based upon a paper by Alves et al.

Conservation importance

Much of the statutory protection for migrant waders is based upon sites used in the non-breeding season. Eveling Tavera has shown that Paracas is important for the whole year. Are there other sites that hold 20% or more of their flocks of Semipalmated Sandpipers for the whole year? What are the conservation implications for this species, which is already designated as ‘near-threatened’? Are we doing enough to look after pre-breeding (and non-breeding) flocks? This issue is discussed further in Teenage Waders, built around a Hudsonian Godwit paper by Juan Navedo & Jorge Ruiz.

In conclusion

An individual Semipalmated Sandpiper does not, of course, have the experience or capacity to enable calculation of differential survival rates. The decision to migrate north will be based upon circumstances and the bird’s condition. Effectively, it is trading off the fitness benefit of higher survival against the fitness cost of a foregone breeding opportunity – but it does not know that that is what it is doing. What is interesting, in this study, is that the cost-benefit analysis so closely matches what is found using field data from this particular site. The survival rates and percentage of non-breeding Semipalmated Sandpipers in Suriname or at another site in Peru may well be completely different but could still balance out. There is so much more to learn about shorebird migration.

Oversummering juvenile and adult Semipalmated sandpipers in Perú gain enough survival to compensate for foregone breeding opportunity Eveling A. Tavera, Glenn E. Stauffer , David B. Lank and Ronald C. Ydenberg. Movement Ecology 8,42. https://doi.org/10.1186/s40462-020-00226-6


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

WaderTales wins BTO Award

I am using this brief WaderTales blog to say ‘thank you’ to the BTO for kindly presenting me with the 2020 Dilys Breese Medal, in recognition of the role that WaderTales plays in the dissemination of BTO science relating to waders. Some of these blogs are listed below.

Receiving the Dilys Breese Medal is very special. It’s an honour to follow previous recipients such as Chris Packham and Michael McCarthy but it’s more personal than that.

Before I worked for BTO I was a Council member of the Trust for several years, at a time when Dilys Breese was also a Trustee. Later, during my time as a member of BTO staff, Dilys continued to be an active Council and working group member, culminating in her role as Hon. Secretary (1998-2001).

In 2007, Dilys died and we learnt that the BTO was to receive a significant legacy which was subsequently used to reinvigorate nest recording.  Paul Reddish, who was acting as Executor, and I wanted to make sure that Dilys would be remembered beyond the end of her gift. With this aim in mind, BTO created the Dilys Breese Medal, awarding the first six medals in 2009 and one a year thereafter.

Dilys Breese

Few people who are reading this will have known Dilys Breese but they will recognise her through her TV productions, especially her work for the BBC Natural History Unit. She created the Living World and Wildlife series for the BBC, before leaving the Corporation in 1991 and setting up Kestrel Productions. Her 1987 Meerkats United programme, with David Attenborough, is probably her most famous programme but there were many more highlights over a distinguished radio and TV career.

Dilys became a BTO member in 1973, bringing many BBC and Kestrel films to annual conferences, working with Chris Mead and others to increase the profile of the Trust and playing an active role in the charity’s governance. Dilys Breese fervently believed that nature and science should be shared with as many people as possible and I am happy to play my part in doing just that.

WaderTales and the BTO

WaderTales blogs that are about BTO-led research and surveys have included:

BTO staff are involved in a study of breeding Curlew in Breckland
  • Why are we losing our large waders? The BTO’s Director of Science, James Pearce-Higgins, is lead author of a review of the problems facing all of the curlews and godwits of the world
  • Curlews can’t wait for a treatment plan. Sam Franks is lead author of a joint BTO/RSPB review that helped to establish the key gaps in our knowledge of problems faced by Curlew, setting the direction for Curlew conservation science and interventions.
  • Do population estimates matter? This blog summarises the ‘waders’ section of the population estimates paper in British Birds, based on data from the Wetland Bird Survey.
  • 25 years of wader declines is a nice example of long-term survey work by Mike Bell, a BTO volunteer and Regional Representative, written up with John Calladine of BTO Scotland.

The Dilys Breese medal

The Dilys Brees Medal was designed by Norfolk artist Robert Gillmor. It features a Robin, the subject of a book that Dilys was working on at the time of her death, set against the outline of an old fashioned TV screen. This will be a lovely memento of fifteen years of working with Dilys to promote the work of the BTO. I am grateful to Mary Colwell (author of Curlew Moon) who kindly nominated me for the award.

Graham Appleton

Click HERE to see more blogs from the first five years of WaderTales

Spoon-billed Sandpipers: Track and Trace

The cutest wader in the world has to be the ‘critically endangered’ Spoon-billed Sandpiper, a tiny wader with an ice-cream spoon for a bill. An ever-reducing number of pairs breed in the coastal tundra of north-east Russia. They migrate to south-east Asia, spending the winter months anywhere between China and Bangladesh.

During autumn there are sightings of moulting Spoon-billed Sandpipers around the mudflats of the Yellow Sea (People’s Republic of China, Democratic People’s Republic of Korea (DPRK) and Republic of Korea). Where else do Spoon-billed Sandpipers go? A new paper shows that it is possible to trace potentially important missing sites by tracking individuals.

Away from their breeding areas, Spoon-billed Sandpipers are threatened by:

  • Loss of non-breeding habitats, especially intertidal mudflats, because of land-claim projects to create harbours, industry zones, wind and solar power generation farms, aquaculture ponds and rice-fields.
  • The spread of invasive Spartina species (cordgrass) across mudflats in some coastal areas of China, the Republic of Korea and Japan is reducing the available feeding area.
  • Local hunting pressure, for personal consumption and local trade.
  • Accidental losses of birds tangled in permanently set fishing nets.

There is more about these issues and efforts to reduce problems being faced by waders on the East Asian-Australasian Flyway on the Saving the Spoon-billed Sandpiper website.

Better information on the location and timing of use of stopover and wintering sites is essential if conservation measures to prevent hunting and further losses of intertidal habitat are to be applied across the species’ range. In a new paper in Wader Study, Prof Qing Chang and colleagues describe in detail the post-breeding migration of adult Spoon-billed Sandpipers. For the first time, they are able to report on the timing of the migration, the duration of stay at stop-over sites, and the distances travelled between stop-overs.

Six Spoon-billed Sandpipers were caught in Chukotka

The research team captured 13 adult Spoon-billed Sandpipers and fitted each bird with a solar-powered transmitter that reports the bird’s locations, via satellites. Six were caught on their nests in Chukotka and seven were netted at Tiaozini in Jiangsu Province, near Shanghai in China. The paper contains full information on the tags, which were glue-mounted to the back of the birds, and details of the data collected and the algorithms used to interpret groupings of locations. This will be of help to anyone considering using these devices.

Why use Satellite transmitters?

Information from colour-ringing and counting has produced fascinating information about Spoon-billed Sandpipers. We now know more about the breeding, migration and wintering locations of the total population, estimated at just 660 individuals in 2014, than we did in 2010, when the serious plight of the species became more widely apparent (Clark et al). There has been international support for conservation action in non-breeding hot-spots in Myanmar, Bangladesh and China, where waders are benefiting from measures designed to reduce hunting pressure and maintain feeding habitat.

Counting waders in the Gulf of Mottomar in Myanmar

The amount of information that can be obtained from counts and colour-ring sightings is limited by knowledge of where to look for birds. There are still big questions to ask. Where do birds colour-ringed in Russia, but not yet seen, spend the winter, where are the breeding grounds for birds ringed in the winter and then not seen in the summer, and what happens to birds in the weeks when they are on migration? Geolocators or satellite transmitters might provide some answers.

Geolocators are great, but information can only be downloaded from these devices by recapturing tagged birds and there is poor precision of reports received during the equinox periods (late March and late September), when daylength doesn’t change with latitude and many waders are on the move. Additionally, given the tiny size of the population and the mobility of breeding birds, recapturing birds to remove geolocators is unlikely to be as easy as it has been for many other wader species. Finally, as has been discussed in a previous WaderTales blog, geolocators can have unanticipated negative consequences for small calidrid sandpipers.

Health & Safety

Every Spoon-billed Sandpiper is precious, so safety is of paramount importance in tagging studies. Prior to deployment on Spoon-billed Sandpipers, tags of the same weight and dimensions were trialled on ‘surrogate’ birds – a small flock of twelve captive-reared Dunlin. The health of these birds was monitored in an aviary and birds seemed to behave normally. Would the same be true for similarly-sized Spoon-billed Sandpipers that migrate thousands of kilometres? Imagine the relief when the first tagged wild bird took off a few days after tagging and started to reveal unique insights into the species’ migration!

From Russia with tags

The six adults captured on the nest and tagged in subarctic Chukotka, Russia, left in July and moved west and south through Kamchatka in July and early August. This was followed by long flights (>1,000 km) across the Sea of Okhotsk to Sakhalin Island. By this stage, only four of the tags were still functioning but these birds provided some fascinating information:

  • All four birds used the same area (Tyk Bay) on the western side of Sakhalin Island. They stayed for long periods and all flew long distances when they left – which means that this site and the resources it provides are really important!
  • The next leg of the journey took the birds further south to sites within Russia and to the Democratic People’s Republic of Korea. All four ended up in DPRK.
  • Two birds stayed long enough to moult close to the Demilitarised Zone in the DPRK but the other two moved on and spent a month moulting at two different sites in Jiangsu Province, China.
  • By this point, in the late autumn, it is believed that all four birds had moulted. Given the method of tag attachment, it was thought that birds would drop their tags during moult, but one bird (L07) continued to transmit data.
  • The four individuals that were tracked between the breeding area and their presumed moulting sites stopped for 2 days or more at between 3 and 7 sites.

Post-moult migration

Seven birds were tagged in Tiaozini in Jiangsu Province. With L07 still transmitting, that meant that there were eight birds to track during the next stage of the migration season. Would they be able to trace missing sites that could potentially be protected.

  • All eight of these birds moved west and south in October or early November.
  • Three birds moved to separate sites in southern China, where they remained until their tags ceased to provide data.
  • Five birds visited stopover sites in China before moving on to their wintering areas in Vietnam, Myanmar, Sumatra and Bangladesh. Sumatra is outside the previously-known wintering range.
  • One of the birds that flew to Bangladesh stopped in Vietnam and Myanmar, while the other one stopped in the Gulf of Thailand. It then overflew Malaysia, Myanmar and the Bay of Bengal before transmissions ceased just before arrival in Bangladesh.
  • The eight individuals that were tracked between moulting and wintering grounds trace out a vast coastline (figure) – illustrating the conservation challenges of trying to save the Spoon-billed Sandpiper. Only two of the birds finished up at well-known sites that are covered regularly by winter counts.

Identifying sites of conservation importance

With only thirteen tagged birds providing four links between breeding and moulting areas and eight links between moulting and wintering areas, the research team have greatly increased our understanding of how it might be possible to protect Spoon-billed Sandpipers. As the authors point out in their Discussion, however, the “list of stopover sites is not comprehensive because of the small number of birds tagged and the duration of stay criterion we used”. Seventeen sites were visited by only one bird and other sites where Spoon-billed Sandpipers are regularly seen were not visited by any of the tagged birds. This suggests that there are probably other important sites that are yet to be traced. The authors suggest some of the limitations created by sampling. The key findings are:

  • During the post-breeding migration, several sites appeared to be of special importance. Seven stop-over sites were used for long periods or were used by birds immediately before long flights (or both).
  • Tyk Bay (Sakhalin, Russia) and Ryongmae Mudflat (DPRK) were used as stopovers by all the tagged birds that passed beyond these sites. Neither site was previously thought to be important for Spoon-billed Sandpipers.
  • The post-breeding moult period is an energetically expensive stage of a wader’s annual cycle. For Spoon-billed Sandpipers, Ryongmae Mudflat (DPRK), Tiaozini (China) and Yangkou (China) are of special importance in this regard (Green et al. 2018, Chang et al. 2019, Yang et al. 2020).
  • Most of the sites in which tagged birds spent the winter months had not previously been visited by count teams. Subsequent visits to some of these previously unknown sites in China added counts of 77 birds.

Once tags had fallen off, birds could still be located by their leg-flags if they were seen by teams of observers who visited known moulting, stop-over and wintering locations. Seven of the birds that carried transmitters have been seen in subsequent years at similar times and places. This suggests that birds are site-faithful between years, implying that a site that is identified to be of importance is really important – birds are not randomly choosing mudflats on a whim.

Yellow 57 – also known as Y57

The stopover-site clusters of registrations were all located on or near coasts, except for one, used briefly, on sandbanks in the Irrawaddy River, Myanmar. Most clusters included areas of intertidal mudflats, especially on estuaries. However, a few included other habitats, such as saltpans and fishponds in impounded areas which had previously been intertidal. Ten of the 28 clusters have some protection under national legislation or international agreements, a further eleven clusters are recognised as Key Biodiversity Areas and/or East Asian-Australasian Flyway Network Sites, but seven clusters appear to have neither protection nor international recognition.

The lack of protection of wintering sites is of concern because of continuing threats to Spoon-billed Sandpipers and their habitats. Hunting of Spoon-billed Sandpipers remains a problem, for instance. This is illustrated by a story from the paper.

During a visit to site Guankoudu (Fujian Province, China) in December 2016, occasioned by the tracking of one of the tagged birds, many mist-nets, more than 2 km in total length, were found, some of which held entangled live and dead shorebirds. This site has no legal protection, but this illegal bird-trapping was reported to local government agencies, whose staff quickly began the removal and destruction of the nets.

If sites are identified, protection is possible.

There may be a Spoon-billed Sandpiper in this cloud of waders over the Taiozini Mudflat

Background to this work on Spoon-billed Sandpipers

The Spoon-billed Sandpiper conservation programme, which includes research, site protection, conservation breeding and head-starting, is a collaboration between the Wildlife & Wetlands Trust (WWT), Birds Russia, Moscow Zoo and the RSPB, working with colleagues from the BTO, BirdLife International, ArcCona, Nanjing Normal University, Spoon-billed Sandpiper in China, Hong Kong Waterbirds Ringing Group, Microwave Telemetry and the Spoon-Billed Sandpiper Task Force.

The project is supported by WWT, RSPB, the UK Government’s Darwin Initiative and SOS – Save our Species, with additional financial contributions and support from BirdLife International, the East-Asian Australasian Flyway Partnership, the Convention on Migratory Species, Heritage Expeditions, the Australasian Wader Study Group of Birds Australia, the BBC Wildlife Fund, Avios, the Olive Herbert Charitable Trust, the Oriental Bird Club, British Airways Communities & Conservation Scheme, New Zealand Department of Conservation, the Queensland Wader Study Group, New South Wales Wader Study Group, Chester Zoo, Wader Quest, Dutch Birding, OSME and British Birds Charitable Trust and many generous individuals. Leica Camera AG is WWT’s exclusive optic partner for this key conservation project.

An assessment of the conservation status of the species can be found on the BirdLife International site:

To read more about the project to set up a captive breeding population and head-start Spoon-billed Sandpiper chicks in their Russian breeding grounds visit the Saving Spoon-billed Sandpiper website.

There is lots of information on the conservation action to protect the species on the Saving the Spoonbill Sandpiper website and on the East Asian-Australasian Flyway Partnership Website. Here’s one example.

Many wader species on the East Asian-Australasian Flyway are threatened by habitat loss, as discussed in this WaderTales blog.

Paper in Wader Study

Post-breeding migration of adult Spoon-billed Sandpipers Qing Chang, Evgeny E. Syroechkovskiy, Guy Q.A. Anderson, Pyae-Phyo Aung, Alison E. Beresford, Kane Brides, Sayam U. Chowdhury, Nigel A. Clark, Jacquie A. Clark, Paul Howey, Baz Hughes, Paul Insua-Cao, Yifei Jia, Elena Lappo, Katherine K.S. Leung, Egor Y. Loktionov, Jonathan Martinez, David S. Melville, James Phillips, Chairunas Adha Putra, Pavel S. Tomkovich, Ewan Weston, Jenny Weston, Nikolay Yakushev & Rhys E. Green. Wader Study 127(3): doi:10.18194/ws.00201


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

The First Five Years

This article celebrates five years of WaderTales. It highlights some of the most well-read tales and picks out a few cross-cutting themes. It has not been possible to include links to all of the 98 WaderTales blogs but you can see them all by clicking HERE.

There are six sections:

  • The most popular stories
  • It all started in Iceland
  • Migration
  • A focus on individuals
  • Thoughts about moult (molt)
  • Conservation issues

The most popular stories

Five blogs on WaderTales have been downloaded 3500 or more times, with the most popular one registering over 10,000 reads. The top five are:

It all started in Iceland

The first WaderTales blog, How volcanic eruptions help waders, was published on 28 September 2015. It explains how the distribution of breeding waders in Iceland is linked to the amount of historical volcanic activity, with ash acting as fertilizer in the central parts of the country. Several other Icelandic studies focus on the ways in which species such as Redshank have taken advantage of opportunities that are provided by farmers’ fields and a warming climate. Designing wader landscapes investigates whether Iceland’s high breeding densities can be maintained, as farming expands and intensification increases.

Migration

Unsurprisingly, migration is a recurring theme in WaderTales. Some of my favourite migration stories are:

  • Which Icelandic Oystercatchers cross the Atlantic? Great teamwork by scientists and colour-ring readers has helped to work out which of Iceland’s Oystercatchers leave Iceland. 70% of birds migrate to Ireland, the UK and western coasts of mainland Europe but 30% ‘tough it out’ in Iceland.
  • Plovers from the north is about Grey or Black-bellied Plovers, a much under-studied wader that travels from the tundra to countries as far south as Australia, Chile and South Africa.
  • Well-travelled Ringed Plovers is an amazing migration story, linking Egypt and Somalia to Chukotka, in the northeast corner of Russia. Here, Ringed Plovers from Africa meet Knot from Australia and Buff-breasted Sandpipers from Brazil.
  • Iceland to Africa, non-stop is about a paper that changed our understanding of the migration of Whimbrel, when geolocators revealed that birds head straight across the Atlantic, on their journeys south. Other Whimbrel blogs talk about the timing of migration and the weather cues associated with decisions made by individuals.
  • Overtaking on migration reveals that Black-tailed Godwits that spend the winter in Portugal, at the southern edge of the species’ wintering range, still get back to Iceland earlier than birds that only have to travel half as far.
  • Teenage waders introducess a previously unknown site in Argentina that is used by non-breeding Hudsonian Godwits in the austral winter. When adults fly north from Chile to Alaska, young birds head inland to the Pampa wetlands. What other habitats do slow-maturing and threatened wader species depend upon?

A focus on individuals

The use of colour-rings, geolocators and satellite tracking has helped to turn the spotlight on individual birds, such as the Greenshank alongside, instead of the patterns we see across populations.

Why is spring migration getting earlier? This early blog focuses on spring arrival dates of Black-tailed Godwits in Iceland. Although the migration season is advancing, individual birds are not changing their annual timetables. Pioneering, new recruits are on earlier schedules than previous generations.

Travel advice for Sanderling introduces the concept of ‘happenstance’ to WaderTales. Colour-ring sightings have shown that Sanderlings from the same breeding areas of Greenland can end up in non-breeding locations that can be anywhere between Scotland and South Africa. Some birds settle in equatorial countries, where the apparent annual survival is lower, from which fewer young birds return to Greenland to breed in their first breeding season, and where it is less likely that an individual will be able to end up on an early breeding schedule. Interestingly, survival rates appear similar in Scotland and Namibia, despite the huge difference in the distance from Greenland. The ‘dice are rolled’ and an individual can end up in a good or poor site, to which it will return every year.

Generational change. In a changing world, with more chaotic weather patterns and rapidly altering habitats, migratory birds are faced with opportunities and challenges. Long-term monitoring of Black-tailed Godwits has shown that migration patterns are forged by new generations, the behaviours of which are moulded by the conditions they encounter in early life.

Thoughts about moult

The main moult of northern hemisphere waders typically happens in the late summer, when the breeding season has finished and once birds have left the breeding grounds. There is then another moult before the start of the next breeding season, as birds change into summer finery (and can change the way they smell). These two moult periods may take up as much as a third of a shorebird’s year but do not get very much attention in scientific studies.

Conservation issues

A lot of the papers that are described above are based upon research that focuses upon species that are of conservation concern. This final selection of blogs highlights a few cross-cutting conservation themes.

Acknowledgements

The purpose of the blog series has not changed since I wrote this introduction on 24 September 2015, but the range of species and the geographic scope have both increased over the years.

WaderTales blogs are used to celebrate waders and wader research. Many of the articles will be based on previously published papers, with the aim of making wader science available to a broader audience. The choice of topics will reflect personal interests, so there will be plenty about Black-tailed Godwits and the international team of scientists who study their behaviours and life-histories. I hope that these blogs will be of particular interest to the hundreds of people who contribute their sightings of colour-ringed Black-tailed Godwits to the ever-expanding database of movements.

There are 98 blogs in the WaderTales catalogue but WordPress tells me that there have actually been 109 posts. The extra eleven represent summaries at the end of each year and occasional syntheses of articles that cover a particular topic, such as migration blogs on wadertales and Wetland Bird Survey: working for waders.

It is humbling to discover that 118,000 people have visited WaderTales in the first five years, however briefly some of them may have stopped by.

I am grateful to all of the authors who have worked with me to make sure that WaderTales blogs properly represent the findings of their research, to the photographers who generously permit free use of their images and to my wife, Professor Jennifer Gill, who encourages and inspires me. It is no surprise that Black-tailed Godwits appear in more blogs than any other species!

There seems to be no shortage of new shorebird research to write about. If you have ideas of topics I should cover or you have an upcoming paper that might turn into an interesting WaderTales blog, please get in touch. A blog works best if I can work up a story in time to share it with the lead author and publish it alongside a paper. Here’s to the next five years!

Graham Appleton

Here’s a link to the full WaderTales catalogue

Flagging up potential problems

Any device that is added to a bird (or other animal) has the potential to affect the way it behaves. Even something as simple as a metal ring could increase risk, if it is fitted incorrectly or if fishing line gets caught around it, for instance.

In a 2020 paper in Bird Study, Thomas Mondain-Monval and colleagues report on the way that differently mounted geolocators affect Common Sandpipers. These devices were being used to help understand the migratory behaviour of the species, part of a Lancaster University PhD project that aims to explain a rapid decline in breeding numbers in England.

Safety first

Any researcher who uses rings, colour-rings, tags or tracking devices to study waders needs to ask (and answer) the following four questions:

  1. Is there a good reason to use the device? What’s the question and will the results be analysed and published?
  2. Is the device being fitted as safely as possible? Has it been used on similar species and what happened?
  3. How do the birds react to the device? If trying something new, perhaps the device can be trialled on captive birds.
  4. Are there any differences between birds wearing different types of rings or devices? Write up your results so as to help future researchers.

Thomas and his colleagues have followed this process through to its conclusion by writing a paper that is published in Bird Study. In it, they compare return rates for Common Sandpipers wearing rings and geolocators and detail a number of injuries that could potentially be linked to the geolocators.

Ringing a Common Sandpiper, before adding a colour ring and a flag

Common Sandpipers

The latest Breeding Bird Survey data suggest that numbers of breeding Common Sandpiper dropped by 40% in England and 24% in Scotland between 1995 and 2018. Over the longer period covered by the three BTO-led breeding Atlases (1968-1972, 1988-1991, 2008-2011) there have been losses from the edge of the species’ range, suggesting that decreases were already under way before the start of BBS recording period (see map). Common Sandpiper was added to the Birds of Conservation concern amber list in 2009. There are insufficient data from the BTO Nest Record Scheme to work out whether declines may be linked to breeding success.

Common Sandpipers in the River Lune study area nest close to running water

The European population of Common Sandpiper has seen a widespread, moderate decline since 1980, indicating that there may be large-scale drivers of losses. Is something going wrong in the non-breeding grounds? Previous geolocator studies have shown that Common Sandpipers rely upon a series of stopover sites on migration (see Not-so-Common Sandpipers) and it is possible that these are declining in quantity and/or quality.

As part of his Lancaster University PhD, Thomas Mondain-Monval’s PhD took a two-pronged approach to an investigation of migration routes. He added geolocators to flags on birds in both England and Senegal. The fact that different tags were used in the two countries enabled him to compare the tag effects on study birds. He was also able to compare tagged birds to a sample of colour-ringed birds.

The study systems

UK fieldwork was carried out in the River Lune catchment area in Cumbria, a northern county of England, as part of a detailed study of 24 breeding pairs. Unmarked adults were caught each year and fitted with a BTO metal ring, a yellow colour-ring (engraved with two unique black characters) and a plain red ring or flag. Similar colour rings were used on Common Sandpipers that were caught on their wintering grounds in Djoudj National Bird Sanctuary, Senegal.

Red flags were used on birds that carried geolocators as these provided space to affix the device. This sample consisted of 22 individuals in the UK and 10 individuals in Senegal. The control samples of birds with colour- rings but no geolocators were 28 individuals in the UK and 6 individuals in Senegal. Dimensions of flags and geolocators are provided in the paper, together with information on methods of attachment. The combined mass of the geolocator, flag and glue was 1.1 g for the birds ringed in England and 1.0 g for the Senegal birds, which is about 2% of body mass of the 50 g Common Sandpipers. The Senegal tags were slightly lighter but a little longer. See paper for details.

Mist nets, drop traps and whoosh nets were used to catch Common Sandpipers that were wintering in the Djoudj National Bird Sanctuary in Senegal

The Common Sandpipers in the UK were observed at least weekly throughout the breeding season. Tagged birds wintering in Senegal remained site-faithful and were observed opportunistically, usually weekly for up to five weeks following capture. It is unusual for researchers to be able to monitor the behaviour of tagged birds as closely as was the case here. When it became apparent that two birds belonging to the breeding study had started to limp, attempts were made to catch the birds. One bird was retrapped and the orientation of the geolocator was changed from parallel to the leg to along the line of the tag. This bird stopped limping and the parallel orientation was not used again.

Flag & geolocator effects

Common Sandpiper in Senegal, wearing a flag-mounted geolocator

The key measures of success that are usually monitored by researchers indicated no difference between birds with and without geolocators:  

  1. For the English, breeding population, there were no significant differences between the return rates or return dates of birds with geolocators and those without.
  2. There were no significant differences in hatching success or fledging success between birds with and without geolocators in either 2017 or 2018, although sample sizes were small.
  3. There was no significant difference in condition between birds with and without geolocators.

Most researchers who deploy geolocators on waders are using them to collect a year’s worth of data from their study birds. Typically, a bird is caught on its nest in one year and then caught again a year later – which might sound easy but isn’t! The fact that Thomas was also studying his small population in detail provided extra opportunities to collect information which should be helpful to others. Although there were no detectable effects of geolocators, as assessed using the metrics described above, a small number of individuals tagged in the UK experienced injuries:

  1. One of the birds that had been fitted with a parallel-mounted geolocator sustained an injury to its lower leg, possibly due to a constriction of blood flow. The bird was still able to continue with its breeding attempt.
  2. On their recapture in 2018, two of the seven birds carrying parallel-mounted geolocators were noted to have bruising on the tarsus, apparently caused by the geolocator hitting the lower leg whilst the bird was walking.
  3. In five cases, individuals had a slightly swollen tibia or had lost some skin underneath the leg flag. This occurred irrespective of tag orientation and appeared to be caused by the internal diameter being marginally too small for the individual, although no rubbing was noted and all flags rotated freely at the time of fitting.
  4. In Senegal, no injuries were seen on any of the tagged birds. These birds were wearing similar flags but carried lighter geolocators than the English birds.

The research team concluded that injuries to the legs of some of the study birds were caused by carrying geolocators. They suggest that they were probably due to a combination of geolocator size and weight, and the short tibias of Common Sandpipers. Mounting long geolocators parallel to the leg on species with short tibias may impede leg movement. When the team switched to thinner and lighter tags for their work in Senegal there were no problems.

It is good that Thomas and his colleagues have published the information about the issues associated with the original tagging method that they used, so that others can learn from their experiences. Had they simply reported return rates and measures of reproductive success their results would have suggested that geolocators had no negative effect on these Common Sandpipers. It would have been easy to miss out the extra detail about the small risk of leg injury.

Bird ringers are always aiming to improve catching, handling and tagging techniques. Within the UK, the use of flag-mounted or harness-mounted geolocators requires project-by-project approval from the BTO’s Special Marks Technical Panel. Annual reporting enables the SMTP to update guidance for other researchers.

Refining the way that flags are used

Flags have been used on waders for over forty years and only occasionally have birds seemed discomforted by being asked to wear them. This seems more likely to happen if the flag is applied to the upper part of the leg. When occasional individuals are observed leg-flicking it may be because the ring sits awkwardly on the tibia-tarsal joint. The flick is thought to rotate the flag into a more comfortable position. Nigel Clark, who affixed his first flag to a Dunlin in 1978 suggests the following remedies:

  1. It goes without saying that the edges of all colour-rings and flags should be sanded to remove sharp edges.
  2. Flags are heavier than colour-rings and this means that they sit more firmly on the tibia-tarsal joint, at a point which is wider in diameter than that of the rest of the tibia. When making flags the internal diameter may need to be slightly larger than that used for colour-rings on the same species.
  3. The addition of a geolocator further increases the mass of the flag. When there were concerns about flag-mounted geolocators in North America, Ron Porter solved the problem by making sure that there was a colour-ring underneath the flag. The ring rotates easily, acting as a ‘washer’ between the tibia-tarsal joint and the flag.
  4. When a wader is very thin, as it may be after a long flight, the diameter of the leg can sometimes be less than expected for the species. In Spoon-billed Sandpipers, where there is only space for one ring on the tibia, flagged birds have occasionally been seen leg-flicking. When the leg-flags were modified, to reduce the internal diameter, things improved.

If there is a paper that describes or expands upon the above list, I shall be delighted to add a reference.

To learn more

This blog focuses on a 2020 paper in Bird Study, the journal of the British Trust for Ornithology:

The effects of geolocators on return rates, condition and breeding success in Common Sandpipers. Thomas O. Mondain-Monval, Richard du Feu and Stuart P. Sharp

Three previous WaderTales blogs have discussed issues relating to flags and geolocators:


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

Teenage waders

Hudsonian Godwit in breeding plumage

A paper by Juan Navedo & Jorge Ruiz, focusing on Hudsonian Godwits, raises important points about the conservation of the world’s larger shorebirds.

Many curlews and godwits don’t breed in their first year but what do they do instead and how quickly do individuals recruit into the breeding population? These answers have direct implications for the conservation of these species, numbers of which are declining in most cases.

Hudsonian Godwits

Hudsonian Godwits breed in Alaska and Canada and spend the non-breeding season in Chile and Argentina. There are three well-separated breeding populations; in south-central and western Alaska, along the northwest coast of Canada (Mackenzie and Anderson river deltas) and within the Hudson and James Bay region of northern Canada. These are indicated in the figure alongside, based on the map from BirdLife International’s datazone.

On migration, Hudsonian Godwits do not use coastal areas, which led to the theory that their journeys north and south might be made without a break. Satellite tracking has revealed that staging areas are continental rather than coastal. The latest research shows that birds wintering in Chile stop off in the prairies of North America on the way north. On the return journey, there are key refuelling areas in Saskatchewan (Canada) and in continental wetlands between Colombia and Argentina. Map below is from a paper from Senner et al.

Satellite tracking of two birds from the Mackenzie Delta breeding population, on Canada’s Arctic coast, revealed a 1500 mile two-day ‘hop’ to Hudson Bay, a long refuelling and moulting period and then a 4 or 5 day direct flight to South America. These are very impressive migrants!

As discussed in Why are we losing our large waders?, the Hudsonian Godwit is still considered to be of ‘least concern’ on the IUCN/BirdLife list. The fact that the species breeds over a broad sweep of Alaska and Canada, even if in discrete areas, and that the population, estimated to be 77,000 individuals (Andres et al 2012), is well over the 10,000 cut-off for threat consideration, means that the species is not yet designated as being of international concern. In Canada, Hudsonian Godwit was added to the ‘threatened species’ list in 2019, as a consequence of reduced breeding success and a major decline in the Canadian breeding population. The latest population estimate in the COSEWIC report is that there are just 41,000 mature individuals (24,300 in the Hudson Bay Lowlands, 800 in the Mackenzie Delta, and 15,750 in Alaska).

Non-breeding youngsters

Releasing a satellite-tagged Hudsonian Godwit

When Hudsonian Godwits depart from the coasts of Chile and Argentina, on their way to Alaska and Canada, they leave behind young birds that will not breed in their first year – and possibly even the second or third. These sub-adults are the future of Hudsonian Godwit conservation. In a declining population, it is important that as many as possible of these youngsters will reach maturity and breed successfully.

Juan Navedo, Jorge Ruiz and colleagues from Universidad Austral de Chile, have been studying the ecology and migratory behaviour of Hudsonian Godwits that winter in Chiloé Island (c. 32°S, Chile) as summarised here. One of the unexpected outcomes of this work is a 2020 paper in Global Ecology and Conservation, entitled Oversummering in the southern hemisphere by long-distance migratory shorebirds calls for reappraisal of wetland conservation policies. In it, they followed the movements of a small number of satellite-tagged adults and discovered significant flocks of non-breeding birds. Their great detective work has clear implications for the potential recovery of Hudsonian Godwit populations and wider consequences for other species of shorebirds that don’t breed in their early year or years of life.

Spring departure

Hudsonian Godwits in Chile are being tracked to improve understanding of the connectivity between their discrete breeding areas and their wintering areas. Tracing their journeys also helps to establish the refuelling areas that are used during northwards and southwards migration.

When it was time to depart from Chiloé Island in spring, most adult Hudsonian Godwits spent a week flying north non-stop over the Pacific, crossed Mexico and staged in the plains of North America but, in 2017, three tagged birds unexpectedly headed northeast to the Pampa wetlands of Argentina. These birds all remained in the Pampa area for five or more months. Their tags provided positions every thirty minutes, supplying the scientists with the information they needed to identify key ‘oversummering’ areas for the species. By focusing on groups of locations for two of the tagged birds, it was possible to identify a 28,000 km2 area that seemed to be of particular importance. Was this where young Hudsonian Godwits (not wearing tags) spent the same period?

The paper explains how the team searched the vast area of permanent and ephemeral wetlands in a systematic way, allowing estimates to be made of the number of shorebirds of a range of species that spend time in this area, instead of migrating north to breed. Hudsonian Godwits were found in four (out of 44) wetlands in 2018 and three in 2019, making a total of 366 and 746 individuals in the two years.

Looking for Hudsonian Godwits in the Pampa Wetlands of Argentina

In their three-day surveys, the team was only able to survey a small number of potential feeding sites within the vast area. On the assumption that Hudsonian Godwits mature at the same rate as other large, long-distance migrant waders, such as limosa Black-tailed Godwits and baueri Bar-tailed Godwits, Juan Navedo and Jorge Ruiz suggest that nearly half of first-year, a quarter of second-year and 15% of third-year Hudsonian Godwits may be using these continental wetlands during a crucial stage of their lives. Numbers of Lesser Yellowlegs and Greater Yellowlegs that they found in the same habitats were also of conservation significance, and the Pampa wetlands are also a ‘summering’ area for Buff-breasted Sandpiper and Upland Sandpiper.

Conservation implications for Hudsonian Godwits

Young Hudsonian Godwits will hopefully breed in Alaska in later years

The paper by Juan Navedo & Jorge Ruiz clearly demonstrates the significance of the Pampa wetlands for waders that were raised in the Northern Hemisphere but which don’t return there until their second, third or even fourth potential breeding season. What is it about these wetlands that is so important to young Hudsonian Godwits, how vulnerable are they and what other inland areas are being used by flocks of young birds? The authors point out that the pampas habitats of Argentina are changing. The Pampa wetlands are being turned into vast swaths of agricultural land, much of which is being planted with herbicide-resistant transgenic soybean. Globally, it is estimated that over 90% of soybean is grown to supply animal feed. This is a thirsty crop that requires irrigation, sucking water out of the remaining wetlands. These grassland habitats are subject to a Memorandum of Understanding on the Conservation of Southern South American Migratory Grassland Bird Species and Their Habitats.

Flagged Hudsonian Godwit

The presence of some adult birds in the Pampa wetlands flocks is not surprising. As discussed and referenced in the paper, individuals that migrate long distances and that are on tight schedules may need to skip the occasional breeding season if they do not have sufficient fat reserves to head north on schedule. When studying tracked individuals of migratory shorebirds that undertake long, non-stop flights, it has been shown that birds occasionally abort their journeys if they encounter adverse weather conditions. We know that godwits of other species can live for thirty years or more so there is always next year.

Wider implications

The Hudsonian Godwit paper is not just about one species. It asks important questions about the conservation of waders and other families of birds that do not breed in their first year. Globally, have we identified the most important shorebird sites, can we protect them from development and are some sites more important than others? Do we pay these sites enough attention in the breeding season, when the large swirling flocks have departed, leaving much smaller aggregations of non-breeding birds sparsely distributesd throughout flyways? Protecting these small oversummering flocks is investing in the future of threatened wader species.

Site protection: This paper has highlighted an important issue. What do young curlews, godwits and other large and medium-sized waders do in the ‘teenage’ years – that important period between being a juvenile and being a breeding adult? Where are they? Are the sites protected? Do birds simply stay in the areas in which they settle in August, September or October, after they have flown south from the breeding grounds? The Pampa wetlands of Argentina are unlikely to be the only non-coastal areas that are used by young waders; what other sites are we missing? For Hudsonian Godwits, perhaps there needs to be a broader definition of key shorebird areas when considering candidate sites that need to be protected as part of the excellent Western Hemisphere Shorebird Reserve Network? More broadly, the authors propose that conservation agreements regarding wetlands of international concern should include a specific criterion for oversummering areas.

Figure illustrating delayed maturity of Hudsonian Godwits (from Navedo & Ruiz)

Youth clubs: Young waders recruit to the breeding population at different ages. If the typical life expectancy of a godwit is ten years then a bird that flies north in its second summer will, on average, produce 12% more chicks in its life-time than one that does not breed until a year later. Hudsonian Godwits not only need to survive in these Pampa youth clubs, they also need to thrive.

Within the same species, time of first breeding can be influenced by the non-breeding site than an individual happens to use. In their fascinating paper about Sanderling migration, summarised in the WaderTales blog Travel advice for Sanderling, Jeroen Reneerkens and colleagues showed large difference in the proportion of young birds that travelled north in the first summer. Most Sanderling that spend the winter in England and Portugal fly to Greenland in spring but only a tiny proportion of birds wintering in Ghana have this extra breeding attempt. They link these differences to site quality.

Eurasian Curlew and a young Black-tailed Godwit

Disturbance: When the number of Eurasian Curlew on a British or Irish estuary drops rapidly, in March and April, and when adult Far Eastern Curlew leave Australia to head for eastern Russia, do we pay enough attention to the small number of birds that remain?

In the northern hemisphere, in particular, the summer months of May through to July bring increased disturbance pressure to beaches and to estuaries, at a time when non-breeding waders are trying to find the resources they need to undertake their primary moult. Perhaps more thought needs to be given to zoning recreational activities in areas which are internationally designated as conservation areas? A May count of 27 Eurasian Curlew on the Exe Estuary in Devon may seem trivial, when compared to 849 in August (Wetland Bird Survey 2018), but these birds represent the future.

In summary

As Juan Navedo & Jorge Ruizwrite in the abstract of their paper:

Given their delayed maturity, many long-distance migratory shorebirds may spend large portions of their lives in previously undocumented wetlands, while deferring migration. These unrecognized oversummering habitats fall outside the scope of today’s conservation efforts for Hudsonian Godwits, because they are not spatially nested within the non-breeding grounds, an issue to be studied for other shorebirds.

We are seeing rapid declines of many of the Numeniini family (see this blog about curlews, godwits and Upland Sandpiper) and other slow-maturing shorebird species, and ‘teenage birds’ deserve more attention. We have to identify the areas used by immature birds as quickly as possible, before productivity is so low that we cannot find them.

Oversummering in the southern hemisphere by long-distance migratory shorebirds calls for reappraisal of wetland conservation policies. Juan G. Navedo & Jorge Ruiz. Global Ecology and Conservation doi.org/10.1016/j.gecco.2020.e01189

Wintering Hudsonian Godwits on Chiloé Island, Chile.

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

Cycling for waders

This blog is mostly about Black-tailed Godwits but there’s stuff about cycling too!

If you’re a Black-tailed Godwit, a 2800-mile (4500-km) direct flight from East Anglia to West Africa is estimated to burn 1085 Calories (4500 kJ) of energy (Alves & Lourenço). Fuelled by Cambridgeshire worms, a female godwit that was raised by the Project Godwit head-starting team flew from the Nene Washes to wetlands in south-east Mauritania in just two days. ‘Cornelia’ – as she was named – undertook this marathon journey with no pre-season training. She just took off on 13th August and arrived on the 15th.

To raise money for Project Godwit and for research projects funded by the International Wader Study Group, Jen and Mark Smart cycled from Somerset to East Anglia, on a 600 mile (960 km) journey that links sites that have been visited by head-started Black-tailed Godwit chicks. Each of them burnt 15,000 Calories (62,800 kJ) over the course of eight days, taking in high energy foods as they travel and stopping to feed and rest each night. Unlike Cornelia, Mark and Jen had been training for years.

Quick reminder of head-starting

Black-tailed Godwits breeding in East Anglia face huge challenges, as you can read below. Four years ago, their situation had become so perilous that it was decided that the only way to stop them disappearing completely was to hatch eggs in incubators and raise chicks in captivity. You can read more about head-starting here. Project Godwit is a partnership between RSPB and WWT, with major funding from the EU LIFE Nature Programme, the HSBC 150th Anniversary Fund, Natural England, the National Lottery Heritage Fund through the Back from the Brink Programme, Leica and the Montague-Panton Animal Welfare Trust.

The maps below show the two breeding sites (Ouse and Nene Washes) and all the late-summer passage sites where head-started birds have been seen in England (left), and the international sightings of all godwits ringed in these breeding sites.

International Wader Study Group (IWSG)

The International Wader Study Group brings together everyone who has a passion for waders (shorebirds), the habitats they use and their conservation. Members include research scientists, citizen scientists and conservation practitioners from all around the world. IWSG gives out small grants each year that help to support wader projects around the world. Recent grants have been used to discover the wintering areas of Common Sandpipers, to measure the site-faithfulness of Dotterel and to support projects in Azerbaijan, Albania, Bangladesh & Argentina.

Mark and Jen

Jen Smart has worked for the RSPB for 14 years.  As a scientist, she led RSPB’s research into the conservation problems faced by breeding waders and developed solutions to help these species. See the WaderTales blog Tool-kit for wader conservation. She developed the science programme around Project Godwit and maintains a keen interest in the project. Jen is Chair of the International Wader Study Group.

‘Manea’ arrived at Old Hall Marshes (Kent) with his sister, ‘Lady’, in July 2017

Mark has worked for the RSPB for 26 years and is Senior Site Manager at Berney Marshes, a 600 ha grassland nature reserve with around 300 pairs of breeding waders. See the WaderTales blog Managing water for waders. As well as managing the reserve, Mark works with other land managers across the country to develop and implement ways of improving habitats for breeding waders.

Latest news from Project Godwit

Project Godwit has been trialling the use of head-starting (https://projectgodwit.org.uk/), where young godwits are reared in captivity, safe from predators and potential flooding, and released once fledged. The aim is to boost the number of godwits breeding in England. The cycle route for Mark and Jen links eleven nature reserves in England, managed by a range of conservation organisations, where head-started Black-tailed Godwits have been spotted on migration by local birdwatchers.

Nelson is one of the birds carrying a geolocator but he has not been recaught (yet)

The ride started at WWT Steart Marshes in Somerset; visited by a Black-tailed Godwit named ‘Nelson’ in 2017. Birdwatchers throughout England were put on alert when the first head-started Black-tailed Godwits were released in 2017 but it was a surprise when Nelson headed southwest. Nelson is a star of Project Godwit. He returned to the Ouse Washes in 2018 and paired up with another head-started bird called ‘Lady’. They have met up in each subsequent spring. In February, Nelson spends time on the Tagus Estuary in Portugal but we don’t know whether he is one of the limosa Black-tailed Godwits that winters south of the Sahara.

The map below shows the route taken by Mark and Jen. The original plan was to cycle from Norfolk to the IWSG conference in Germany, which neatly linked the two causes for which they are seeking sponsorship – Project Godwit and the IWSG fund to support wader research. When the conference was rescheduled as an on-line meeting, they decided to join up the godwit dots across England. The 600-mile bike took just over a week.

Jen & Mark’s route links RSPB, WWT, Wildlife Trustand county wildlife sites between Somerset and Cambridgeshire.

The last site to be visited was the Nene Washes where, as mentioned above, the Black-tailed Godwit ‘Cornelia’ returned to breed. Having been raised at Welney, she was released at the Nene Washes on 27 June, 2018, wearing a small geolocator attached to a flag on her lime ring (see earlier picture). She is the only bird for which the RSPB and WWT team have a whole-year migration history. Cornelia was caught on a nest at the Nene Washes in 2019 and her geolocator was removed. In his blog on the Back from the Brink website, Mo Verhoeven shares his excitement when he learned that this young bird had flown directly from the Nene Washes to wetlands in Mauritania in just two days. There is more about Cornelia here.

Conservation challenges

Wetlands are under threat across the globe and it is appropriate that Mark and Jen are raising money for the International Wader Study Group and for Project Godwit. As they tweeted about their travels and talked about Black-tailed Godwits at local press events, at different nature reserves, they revealed some of the conservation challenges that waders face.

The RSPB nature reserve at Titchwell (North Norfolk) is a favourite pit-stop for Project Godwit birds. These three youngsters, all head-started in 2018, visited before flying south.

Project Godwit is not just about head-starting more Black-tailed Godwit chicks. The team is trying to improve the chances for nesting birds out on the Washes, using electric fences and other predation reduction schemes, and through the development of alternative breeding areas that are under less threat of flooding during spring and summer deluges.

Within Britain and when they head south through Europe and into Africa, Black-tailed Godwits are dependent upon a network of sites. Some of them are fully-protected nature reserves, others have been given international recognition as SPAs and Ramsar sites, but there are many other locations that are important but not designated. Sightings of Project Godwit birds and locations downloaded from geolocators will help to identify areas in which birds may be vulnerable to habitat change and new developments.

A new airport that is planned for the Tagus Estuary is a huge threat to limosa Black-tailed Godwits that breed in Western Europe, including the small English population. It’s thought that about half of the Project Godwit birds use the rice fields and mudflats of the Tagus Estuary, as you can read in Black-tailed Godwits are on their way home. As mentioned above, Nelson has been seen in the Tagus Estuary on several occasions (see map alongside). The proposed airport threatens many species of migrant waterbirds (Tagus Estuary: for birds or planes).

An important unknown when trying to conserve our larger wader species is ‘what happens to the teenagers?’. When do species such as Black-tailed Godwits start to breed and what do they do in the period between fledging and breeding? A key part of Project Godwit is to mark chicks in the wild, as well as head-started birds, hopefully answering questions such as ‘what proportion breed in their first year?’ and ‘where do immature birds spend the pre-breeding years’? Perhaps the International wader Study Group will be able to support similar work for other large shorebird species, through its small project grants?

Support for Mark and Jen

This epic sponsored cycle ride is funding work by Project Godwit and the IWSG. It was a great opportunity to thank colour-ring readers who have reported marked birds, to emphasise the importance of protecting networks of sites for migrant waders, and to highlight some of the conservation challenges that lie ahead.

If you would like to help Mark and Jen to support International Wader Study Group Small Projects Grants, please donate here: https://www.waderstudygroup.org/donate/

If you would like to help Mark and Jen to support the RSPB’s contribution to Project Godwit please donate here: https://www.justgiving.com/fundraising/fundsforwaders


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