Winter conditions for Whimbrel

Up until relatively recently, it was hard to study the same population of migratory waders in both its breeding area and its wintering grounds. Ringed birds established links between different countries but to follow a group of individuals through a complete annual cycle was nearly impossible. Geolocators, and more recently satellite tracking, are starting to enable scientists to piece together whole stories.

Camilo Carneiro and colleagues from the University of Aveiro in Portugal (Dep. Biology & CESAM) and the University of Iceland (South Iceland Research Centre) have been tracking Whimbrel travelling between Iceland and Africa for nearly ten years, using geolocators. In the latest paper to come out of this research they investigated carry-over effects; do conditions experienced in wintering locations affect breeding success?

How might carry-over effects work?

The conditions experienced during one stage of a migrant’s annual cycle may affect their performance in subsequent stages. Perhaps the resources available at a wintering site might affect the timing of spring departure and whether an individual has to stop off to refuel? In turn, such individual differences may be apparent in individuals’ arrival dates in the breeding area, and the condition they are in might affect laying date, clutch size, egg weight, etc?

Icelandic Whimbrel spend the wintering season anywhere between south-west Europe and the tropical coastal areas of West African countries such as Benin and Togo. Despite this huge non-breeding range, individuals are highly philopatric, travelling between the same breeding area and the same restricted wintering site on an annual basis, perhaps for twenty or more years. A Whimbrel flying to the Bijagós Archipelago of Guinea-Bissau covers nearly 6000 km, in the autumn, whereas a bird that only travels to the Tejo (Tagus) Estuary of Portugal flies not much more than half as far (see map). The ‘winter’ conditions they experience are completely different; short temperate days in Portugal or tropical heat in the mangroves in Guinea Bissau.

Camilo and colleagues were able to study Whimbrel in different wintering locations, in order to understand the conditions that are experienced by breeding birds from these areas. They measured annual return rates for birds that had flown different distances and experienced different conditions in the non-breeding season. Do Tejo birds, spending the non-breeding season in the coldest part of the wintering range, have a lower apparent chance of survival? Do those that make it through a Portuguese winter return to Iceland earlier and thereby increase their chance of breeding successfully?

Life on the wintering grounds

Camilo Carneiro has studied wintering Whimbrel in three sites – the Tejo Estuary (Portugal), the Banc d’Arguin (Mauritania) and the Bijagós Archipelago (Guinea-Bissau). Birds in the three sites experience very different conditions between the start of September and the end of March, as discussed in the paper and illustrated in the table below.

Hundreds of observations of individual Whimbrel and flocks provided information on feeding rates, diet and foraging time. Comparable food items were collected from the mud/sand substrates and the energetic values were calculated in the laboratory. Together, these data enabled a calculation of energetic intake. The Net Energetic Intake Rate varied markedly. The figure for the Bijagós is 3.9 times that of the Tejo and 1.4 times that of the Banc d’Arguin.

Crabs provide a large part of a Whimbrel’s winter diet

Birds have a basic running cost – the Basal Metabolic Rate – which is related to the size of the individual and ambient conditions it experiences. Those wintering in areas where they experience periods of colder and windier weather lose more heat and hence need more energy. The BMR was calculated as 2.17, 2.29 and 2.51 Watts for individuals wintering in the Bijagós, Banc d’Arguin and Tejo, respectively, showing that there are higher ‘running costs’ in northern sites. Whimbrels in the Bijagós never incurred energetic costs above BMR, whereas those in the Banc d’Arguin and Tejo had additional energetic costs on 20.6% and 9.7% of the winter days, respectively.

The daily energetic balance differed hugely. Whimbrels in the Bijagós experiencing an average energetic surplus of about 700 kJ/day, followed by 420 kJ/day in Banc d’Arguin and just 11 kJ/day in the Tejo. It should be noted that these figures are based only on day-time feeding.

A colour-ringed bird hiding in a Bijagós flock

Returning to Iceland

The research team has shown that Whimbrel can either fly directly to Iceland or stop off and refuel. It is thought that between 80% and 90% of journeys include a stop-over, typically in Ireland or western Britain. Direct flight takes four or five days. (see summary of previous papers and blogs below).

Whimbrels arrive back in Iceland between the end of April and late May, quickly taking up territories unless there is snow cover. Regular visits to the main study area in the Southern Lowlands helped to ascertain which colour-ringed birds had returned when. Nests are found, and eggs are measured and ‘floated’, to estimate the laying date.

During incubation, attempts were made to catch marked individuals that were carrying leg-mounted geolocators. Adults trapped on the nest are measured, unringed birds are marked and three to five feathers are removed from the breast. These feathers will have been grown in the bird’s wintering area and carry an isotopic signature from that region.

Using stable isotope analyses of the breast feathers, ground-truthed by birds tracked using geolocators, Camilo managed to assign the winter location to 180 Whimbrels. 159 had flown from the tropical region (which includes Bijagós), while 20 had spent the winter in the arid region (which includes Banc d’Arguin) and one in the temperate region (Tejo). When linking the wintering region to breeding phenology and investment, the research team found that:  

  • There were no differences in the size of the birds returning from the tropical and arid regions.
  • There was no difference between the probabilities of a bird successfully returning from the tropical and arid regions.
  • The timing of nesting and the volume of the eggs that were laid by females was not different for birds from the tropical and arid regions.

Where to spend winter?

Only one marked bird definitely wintered in temperate southwest Europe, which is not surprising given that there are not large flocks of Whimbrel in the estuaries of this area. This bird was excluded from the analyses but we know that it will have travelled much less far than birds wintering in Africa and experienced winter conditions in which it could barely meet its daily energy requirements.

Individuals wintering in the arid region, including birds in the Banc d’Arguin, travelled a lot further than birds wintering in southwest Europe. These birds had an expected surplus of 420 kJ per day on an average day but strong winds meant that there were 20% of winter days in which conditions were sub-optimal.

Trying to find Whimbrel in a sandstorm in Banc d’Arguin

Individuals wintering in the Tropical group, including birds in the Bijagós, travelled 900 km further than the Arid group but found more predictable weather conditions, achieving an estimated spare energy capacity of 700 kJ per day, without days with energetic costs above BMR. The authors point out that this energy surplus will likely be needed during long periods of moult and to fuel spring migration.

The authors conclude that any costs associated with having to fly further to reach the tropical region are compensated for by benign conditions. This does not mean that an individual bird makes a choice between Tejo, Banc d’Arguin and Bijagós. Happenstance may determine where a juvenile ends up in its first winter and philopatry means that, if alive, it continues to spend subsequent winters in the same area. Presumably the risks incurred by flying further (to Bijagós) balance out the risks incurred by wintering in a less predictable environment.

Life in and amongst the mangroves of the Bijagós

Very few Whimbrel spend the winter on the Tejo, in Portugal, and calculations in the paper suggest that there is a high risk of not being able to find enough food. This would probably translate into high mortality and explain low numbers.

Carry-over Effects

Although no carry-over effects were found, the authors discuss ways in which they may show up in other traits. There is an interesting discussion as to how carry-over effects might link experiences in the wintering grounds to breeding output in the next breeding season. Amongst other things, the authors suggest that differences among individuals using different wintering sites may only become evident if assessed over several years. We know that conditions are less benign in Banc d’Arguin, for instance. Perhaps there are years when conditions are bad enough for long enough to influence survival or body condition in spring. In such a year, there could be impacts on the ability to migrate, an increased likelihood of dying during migration or delayed breeding. It is possible that longer-term studies will pick up differences in return rates and/or breeding success for birds wintering in different areas? We shall see.

Paper

Linking range-wide energetic trade-offs to breeding performance in a long-distance migrant Camilo Carneiro, Tómas G. Gunnarsson, Verónica Méndez, Amadeu M.V.M. Soares & José A. Alves

Previous research on Icelandic Whimbrel

This Whimbrel, photographed in Bijagós is wearing colour-rings that were fitted in Iceland

Whimbrels on the move summarised the movements of Icelandic birds, based on reports of ringed and colour-ringed individuals. In the paper upon which the blog was based (Gunnarsson & Guðmundsson) there was a strong suggestion that birds only stop off in Britain & Ireland on the way north. Geolocator-based research by Alves et al showed that at least some birds were flying straight from Iceland to West Africa and that these sea-crossings could be very rapid.

Migrations to and from Africa were investigated further in a paper by Camilo Carneiro et al that was summarised in Iceland to Africa, non-stop. More recently, papers by the same team have shown that the most consistent point of the annual migration story is departure from Africa and discussed the links between weather and phenology. These two papers have appeared as the WaderTales blogs – Whimbrel: time to leave and A Rhapsody of Whimbrel.

Further reading

The following WaderTales blogs all consider how migratory behaviour might affect breeding season success, although without the direct measurements for individuals that have been carried out in the Whimbrel study.

Overtaking on migration shows that potential costs of migrating further can be overcome by undertaking early spring migration to staging sites that are closer to breeding areas.

Travel advice for Sanderling summarises research to understand the pros and cons of spending the non-breeding season in widely different locations.

Gap years for sandpipers is based upon a Peruvian Semipalmated Sandpiper paper that investigates the survival advantage of not migrating north to breed in a particular year.


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.

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.