Following the success of our inaugural t-shirt competition in 2021, and at the request of a number of members we are proud to let you know that we'll be running a new t-shirt competition but this time for our younger members!
We'd like all young waderologists to enter in their best wader designs to be seen on t-shirts and bags on our Teemill website to raise money for supporting the IWSG in its activities (https://waderstudygroup.teemill.com
). There will be two age categories - under 11s and 11-17 year olds and as with the last competition we encourage all original and unique artwork but with the consent of the entrant's parent or guardian.
The winners of the competition will win a t-shirt with their design PLUS a year’s family membership to IWSG whilst the runners up will get a tote bag with their design. All shortlisted designs will be included on our Teemill shop and the winner decided by the attendees at the IWSG conference in Sylt in September 2023
All proceeds from the sale of bags or clothing will be used to support the running of IWSG.
Competition Rules are below and any queries please send them to firstname.lastname@example.org
- Open to entrants under the age of 18 who, with their families, are part of the wider wader/shorebird community with permission of a parent or guardian
- Any design will be accepted as long as it has a wader on it, space for the IWSG logo (which can be small) and on a white background
- Meaningful text regarding waders will be considered for inclusion.
- Enter whichever artistic medium suits – pencil and paper, water colours, PowerPoint, Photoshop but you will need to be able to scan the final image cleanly. Lines must be thick enough to see when printed on fabric (~2mm+)
How to enter:
- Parent/guardian to email a scan of the final design with the young person’s first name & the subject line “IWSG T-shirt Comp” to email@example.com
- Including a line of consent from the parent/guardian for the child's name to be used
- Up to 3 entries per person are allowed and should be original and unique artwork
- Closing date – midnight 23:59 GMT 14th September 2023 (submission deadline updated!)
Full Terms can Conditions IWSG design a tshirt competition_TandC_2023
Following the success of our inaugural t-shirt competition in 2021, and at the request of a number of members we are proud to let you know that we'll be running a new t-shirt competition but this time for our younger members! We'd like all young waderologists to enter in their best wader designs to be seen on t-shirts and bags on our Teemill website to raise money for supporting the IWSG in its activities (https://waderstudygroup.teemill.com). There will be two age categories - under 11s and
by Deborah Buehler originally published in Wader Study 130(1)
For many humans, it means relaxation and recreation. It’s a place to fish, or walk the dog, or sunbathe, or swim. For many shorebird species, the beach is necessary for survival and reproduction. Unfortunately, beaches are not always tranquil. Shorebirds can be attacked by birds of prey or flushed by human beachgoers and their pets. How much does this happen? What causes the disturbance? Can anything be done to reduce the harm?
In this issue of Wader Study
, Khwaja and colleagues harness the power of citizen scientist volunteers to address these questions. Using a standardised monitoring protocol, they collected data on the disturbances that shorebirds face when resting on the beaches of Roebuck Bay.1
Roebuck Bay is a large, tropical embayment in north Western Australia, south of the town of Broome. It is an important non-breeding site on the migration flyway extending from Arctic Russia and North America, along the east coast of Asia, to the southern limits of Australia and New Zealand (the East Asian-Australasian Flyway). Researchers at the Broome Bird Observatory regularly record 29 shorebird species supported by the bay. Because most of these species are migratory and breed in the northern hemisphere, the number of shorebirds in the bay varies greatly between roughly 20,000 individuals through the austral winter (dry season) to roughly 100,000 in the austral summer (wet season). Recently, populations of the migratory species in particular have declined alarmingly within the flyway. Although these declines have been linked to habitat loss in other parts of the flyway (specifically the disappearing mudflats of the Yellow Sea), understanding what happens in Australia improves the chances that the birds will be helped rather than further hindered when they reach the beaches of Roebuck Bay.
The tidal mudflats in Roebuck Bay are extensive, and low spring tides can expose around 175 km2
of mudflats where shorebirds feed. However, such a high tidal range also means that there is a four-hour period around high tide when the mudflats are totally submerged. During these times, the birds need safe places—called high tide roosts— to rest.
[caption id="attachment_17002" align="aligncenter" width="330"]
Mixed shorebird flock roosting on Roebuck Bay’s northern shores at high tide. (photo: Mattea Taylor)[/caption]
Finding a good high tide roost is not easy. Optimally such sites should be close to the feeding areas and have clear lines of sight to spot approaching danger. In tropical areas like Roebuck Bay, these roosts must also be close to the water during daytime high tides to prevent heat stress. When a good site is found, it makes sense to rest and conserve energy for the duration of high tide, but undisturbed roosting isn’t always possible.
Disturbance is usually defined as the disruption of normal activities caused by an animal’s response to an encounter with an external stimulus. Khwaja and colleagues chose alarm flights—when shorebirds take off steeply and rapidly turn to avoid perceived danger—to quantify disturbance. Models suggest that alarm flights are around three times more energetically costly than ‘commuting’ flights when birds move between areas undisturbed.2,3
The researchers then enlisted Broome Bird Observatory (BBO) staff and trained volunteers to conduct systematic watches on five beaches in Roebuck Bay. These study sites represented a range of disturbance levels and had been regular roost sites for shorebirds since at least the late 1990s.
Observers worked in pairs when possible, but when volunteer availability was low, experienced bird watchers could work alone. Teams performed watches at each of the five study beaches, simultaneously, sitting close enough to see any shorebirds present, but distant enough not to disturb them. There were two watch days per month from May 2005 until April 2006, and from August 2019 until July 2020, with one watch-day falling on a weekday and the other on a weekend. To gauge how often the birds were disturbed, observers counted all alarm flights made in the four-hour high tide period. They also estimated the average amount of time the birds spent in flight, by performing a short scan every 10 minutes throughout the watch and noting the proportion of birds in flight. The researchers then calculated the average proportion flying per minute and multiplied by the 240 minutes in a four-hour watch. Finally, they tried to determine what caused the alarm flights and recorded details of any visits made by people to the beaches.
[caption id="attachment_17001" align="aligncenter" width="330"]
Volunteers observing shorebirds during a watch at Crab Creek Beach. (photo: Jane Taylor)[/caption]
The observers completed 214 watches over the two years: 96 in 2005–2006, and 118 in 2019–2020. Birds were present on the beach for 196 of the 214 watches and when birds were present, 2020 alarm flights were recorded: 918 in 2005–2006, and 1,102 in 2019–2020. On average the birds were disturbed 2.44 times per hour and the alarm flights usually involved all, or nearly all, of the birds present on the beach. Across all watches, the researchers estimated that each bird spent about 2.86 minutes per hour in flight.
Several factors affected both the number of alarm flights and the estimated time in flight. First, more alarm flights occurred, and birds spent significantly longer inflight, in the dry season (winter) than the wet season (summer). This makes sense because, in the dry season, birds of prey are more abundant in Roebuck Bay, Broome’s population swells with tourists and seasonal workers, and the access road to the northern beaches (study sites) is less likely to flood. Location of the beach was also associated with the number of alarm flights and time spent in flight, but the effect depended on the year of study. This interaction between location and year means that efforts to mitigate disturbance will need to be tailored to the circumstances at individual beaches over time. Finally, more alarm flights were noted when more birds were present on the beach, perhaps because the presence of more individuals increased the likelihood that one of them would detect an actual or perceived threat.
The researchers were able to identify the apparent cause of disturbance for 60% of alarm flights in 2005–2006, and 71% in 2019–2020. Most alarm flights were triggered by birds of prey (raptors) in both years and it is possible that they may have caused even more alarm flights than recorded. In both years, 29 to 40% of alarm flights could not be traced to a stimulus and birds of prey are more likely than other stimuli to have been missed by observers. For example, a brief, silent appearance by a raptor behind a dune is likely to be missed by an observer and can be enough to provoke an alarm flight. Aircraft are noisier and people disturbing shorebirds usually more obvious.
Human visitors were a less frequently identified cause of disturbance than birds of prey, but still accounted for about 20% of the alarm flights with an identified stimulus. Humans were most often seen walking or fishing on the beach, and walkers were more likely to alarm shorebirds (37% or 33 of 90 occasions) than people fishing (21% or 35 of 167 occasions). This is likely because walkers are mobile while fishers are stationary. However, observations from this study also suggest that fishing might have an indirect effect on disturbance because scraps left by human visitors attract birds of prey to beaches.
The researchers suggest various ways to mitigate human-caused disturbance in Roebuck Bay. Examples include: public awareness campaigns about the importance of not disturbing shorebirds on the beach, information for fishers on the importance of not leaving scraps or bycatch on beaches, and even installing floating roost platforms on beaches where human use is already high, to increase available habitat for birds without reducing accessibility to people.
The biggest challenge in this study, and a challenge for anyone attempting to measure the impact of disturbance on wild animals, is that is that researchers can only assume the consequences of an observed behaviour but cannot directly measure those consequences. Khwaja and colleagues were interested in the energetic costs of disturbance on shorebirds but acknowledge that they made no estimate of the true energetic cost of alarm flights, nor was doing so possible with the data they collected. They estimated a response to disturbance and used that as an index of the actual energetic costs. The use of indices is common but requires assumptions and raises the question of whether the exhibited behavior really means what we think it does.
In the case of alarm flights in Roebuck Bay, the assumption is that alarm flights are costly2
and that when the cost of multiple alarm flights exceeds the cost of a “commuting flight” to a “less disturbed” roost site, the birds will go elsewhere.3
Khwaja and colleagues estimated that shorebirds exceeded this threshold during the winter at all beaches studied in 2005–2006, and at two of the five beaches in 2019–2020. Yet, some birds clearly continue to roost on highly disturbed beaches in winter. What does it mean when a bird stays put? In many studies, staying is interpreted as low disturbance, but is that always the case? Perhaps the birds also experience disturbance at the nearest alternative roost. Perhaps they stay put and endure the disturbance—which also has costs—because they have nowhere better to go.4
This study by Khwaja and colleagues is impressive because the energy of volunteers was successfully harnessed in a standardised citizen science monitoring protocol. In this way, the researchers were able collect robust data on shorebird alarm flights and their possible causes, for two full years fourteen years apart. As we move towards summer and beach season in the north, in Roebuck Bay, the austral winter beach season is also beginning. This study is a nice reminder that though we can’t yet directly measure energetic or fitness costs of disturbing shorebirds, we can do our best to minimize our part in it.
1 Khwaja, N., C.J. Hassell, M.J. Taylor, J.A. Taylor, J. Lewis & D.I. Rogers.
2023. Repeated monitoring suggests shorebirds are disturbed consistently during winter at a globally important roost in tropical Australia
. Wader Study
2 Nudds, R.L. & D.M. Bryant.
2000. The energetic costs of short flights in birds
. Journal of Experimental Biology
3 Rogers, D.I., T. Piersma & C.J. Hassell.
2006. Roost availability may constrain shorebird distribution: exploring the energetic costs of roosting and disturbance around a tropical bay
. Biological Conservation
4 Gill, J.A., K. Norris & W.J. Sutherland.
2001. Why behavioural responses may not reflect the population consequences of disturbance
. Biological Conservation
of this article
Featured image: Bar-tailed Godwit Limosa lapponica
, Orielton Lagoon, Tasmania, Australia. © J. J. Harrison.
by Deborah Buehler originally published in Wader Study 130(1) The beach. For many humans, it means relaxation and recreation. It’s a place to fish, or walk the dog, or sunbathe, or swim. For many shorebird species, the beach is necessary for survival and reproduction. Unfortunately, beaches are not always tranquil. Shorebirds can be attacked by birds of prey or flushed by human beachgoers and their pets. How much does this happen? What causes the disturbance? Can anything be done to reduce the
The Doñana National Park
in the Guadalquivir basin in southern Spain faces an unprecedented challenge! Despite enjoying all possible levels of legal protection, Doñana National Park and its surrounding natural areas are under severe threat due to decades of (ground)water overexploitation, the effects of which are aggravated by a severe ongoing drought. Adding insult to injury, members of the Andalusian Parliament are pushing a new law proposal to regularize almost 2000ha of illegally irrigated land in the area.
As international bird migration experts
we strongly oppose the current law proposal
, which has already been heavily criticized by experts of Doñana Biological Station, the regional water authority of the Guadalquivir basin, the Spanish Minister of Ecological Transition and Prime Minister, the EU Commission, and UNESCO.
In addition, we are extremely worried about the impact of the ongoing drought on rice cultivation
in Guadalquivir basin. Rice paddies provide vital stop-over and wintering habitat for large concentrations of European waterbirds, for which they are also flooded in winter under an EU-subsidized agri-environment scheme. The drought caused the surface of cultivated rice paddies to drop by >50% in the past two years, and will be close to zero in 2023. This represents a major threat to numerous European waterbird populations.
We therefore take the opportunity to publish an open letter
on UN’s World Migratory Bird Day 2023, 13th
May, under the slogan “Water: Sustaining Bird Life
”, to raise awareness about this pressing issue and requesting UNESCO to list Doñana as ‘World Heritage in Danger’. Representing the international bird migration research community, we stress the need for an ambitious, cross-sectoral plan to preserve the key natural values of Doñana NP and the Guadalquivir basin, and in particular its international role for migrant birds; one of the main reasons for which Doñana is listed as World Heritage by UNESCO.
Wouter V., José A., Jocelyn C., Juan N. & Theunis P.
Open letter is available in five languages:
Featured image: current appearance of the Santa Olalla lagoon, the largest permanent lagoon of Doñana ©EBD-CSIC.
The Doñana National Park in the Guadalquivir basin in southern Spain faces an unprecedented challenge! Despite enjoying all possible levels of legal protection, Doñana National Park and its surrounding natural areas are under severe threat due to decades of (ground)water overexploitation, the effects of which are aggravated by a severe ongoing drought. Adding insult to injury, members of the Andalusian Parliament are pushing a new law proposal to regularize almost 2000ha of illegally irrigated
The latest IWSG Small Project Grant has been found!
' project on Arctic skuas' possible defensive umbrella exploited by Ruddy Turnstones
has been awarded with the IWSG Small Project Grant for the field season 2023.
Many shorebirds nest in loose groups or colonies to form a ‘defensive umbrella’ around their nest. The same may apply to Ruddy Turnstones that often place their nests close to Arctic Skua nests, which can fiercely defend their nest. However, Turnstones are also know for robbing the nests of other species such as gulls. Thomas and colleagues will study these colonies of Ruddy Turnstones and Arctic Skuas to find out who exactly benefits the most from nesting together.
[caption id="attachment_16802" align="aligncenter" width="330"]
Thomas Lameris tracking Red Knot chicks in the field using radio telemetry. (c) NIOZ. Royal Netherlands Institute for Sea Research.[/caption]
Since 2016, the International Wader Study Group annually funds small projects to support shorebird studies that otherwise will not go ahead. visit the IWSG Small Projects Grants pages: https://www.waderstudygroup.org/projects/small-grants/
Featured image: Ruddy Turnstone Arenaria interpres
in flight, (c) Jeroen Reneerkens.
The latest IWSG Small Project Grant has been found! Thomas Lameris' project on Arctic skuas' possible defensive umbrella exploited by Ruddy Turnstones has been awarded with the IWSG Small Project Grant for the field season 2023. Many shorebirds nest in loose groups or colonies to form a ‘defensive umbrella’ around their nest. The same may apply to Ruddy Turnstones that often place their nests close to Arctic Skua nests, which can fiercely defend their nest. However, Turnstones are also know
on behalf of Andreas Rimoldi & Vojtěch Kubelka
Dear fellow shorebird researchers and enthusiasts:
We would like to ask you collaboration for gathering data for new research project, where we aim to analyse the camouflage characteristics of adult incubating shorebirds.
Background and research rationale
Nest predation is a significant cause of avian nest mortality, and in ground-nesting species evading nest detection is an important form of anti-predatory strategy. Egg camouflage has been extensively studied, proving how camouflage predicts survival, when studying shorebirds and nightjars. In the same species, escape distance is possibly related to camouflage on individual scale, of both eggs and adults. Additionally, microhabitat selection and modification on individual level increase the individual camouflage of both nests and adults. We are comparatively investigating adult camouflage in incubating shorebirds, testing the individual camouflage against environmental, life history and geographical variables (e.g. nesting habitat from a broader scale to microhabitat selection, and behavioural variables like mating system and other nest-defense and other anti-predatory behaviour, to provide a detailed insight on how shorebirds rely on and use this anti-predatory strategy.
Since it is already known that ground nesting-birds may suffer increase predation rates in changing landscapes, understanding the role of camouflage and how this influences the nest selection sites and survivability will help design future conservation strategies.
Request for data
We are interested in all shorebird species from all over the world, without the help of the IWSG shorebird community we would not be able to cover the whole diversity of those wonderful animals breeding all over the world!
We are looking for RAW pictures of incubating shorebirds, taken in a side view and centered in a representative portion of the nesting environment, with associated data regarding the observed bird. Every camera that can shoot in RAW is suitable for the project. Unfortunately, pictures recorded with nest-cameras, camera traps or digiscoping would not be suitable for this project.
If you already have some pictures with associated information, please get in touch with us and we will be happy to consider them if they meet the set-up criteria. The project is not only for shorebird researchers. If you know a photographer or birdwatcher that would be interested and able to help, please inform them about the project.
In this project, we will use the dataset gathered up to the end of the year 2023 or start of the year 2024 and we will offer co-authorship in the resulting publication(s) to the collaborators providing suitable photographs used in the analyses.
Thank you very much for sharing this opportunity and if interested please get in touch for details.
Andreas Rimoldi (Rimoldi.firstname.lastname@example.org
) & Vojtěch Kubelka (email@example.com
on behalf of Andreas Rimoldi & Vojtěch Kubelka Dear fellow shorebird researchers and enthusiasts: We would like to ask you collaboration for gathering data for new research project, where we aim to analyse the camouflage characteristics of adult incubating shorebirds. Background and research rationale Nest predation is a significant cause of avian nest mortality, and in ground-nesting species evading nest detection is an important form of anti-predatory strategy. Egg camouflage has been
by Deborah Buehler originally published in Wader Study 129(3)
Spotlight: A 30-year effort to study an elusive bird
The ground gives beneath your feet and you know you have to stop. The wetland surrounding you is also known as a mire, a word that gives fitting connotations of sinking and getting stuck. You look at the bird through binoculars, not daring to go further. It is a small sandpiper with short legs and a long, broad bill with a downturned tip. The English name for this bird is, aptly, Broad-billed Sandpiper. The bird’s Norwegian name is “fjellmyrløper”, which translates to “mountain mire runner”. Now you know why. Instead of flying, it runs through the grass-like sedges ahead of you, almost completely camouflaged. You were lucky to spot it. It probably has a nest out there in that floating vegetation, but you know that going further would not be safe for you or the bird you are trying to study.
[caption id="attachment_16698" align="aligncenter" width="330"]
Walking through the mire is a challenge. (photo: Stuart Rae)[/caption]
Given the difficulty of even seeing these elusive birds, it’s no surprise that Broad-billed Sandpipers Calidris falcinellus
are not well-studied. Yet, in this issue of Wader Study
there are two papers, by the same team of researchers, on this species. One, by Robert Rae and colleagues describes the breeding ecology of these birds.1
The other by Brett Sandercock and colleagues focuses on the adult birds’ physical description and annual survival.2
Both refer to a long-term study that has been in place for nearly 30 years.
When the researchers began the study in 1993 the world was a different place. As they established the study site, Nelson Mandela was elected President of South Africa in the country's first multi-racial elections. When they began to capture, and ring incubating birds eBay was launched. No one “googled” anything and technologies like social media and smart phones were more than a decade away. Yet over all this time, the researchers were walking through the mires, studying Broad-billed Sandpipers.
Broad-billed Sandpipers Calidris falcinellus
breed in the subarctic taiga biome and can be divided into two distinct populations: a European subspecies breeding in Fennoscandia (Finland, Norway, Sweden and part of Russia), and an Asian subspecies breeding in central and eastern Russia. Globally, the species has a broad geographic range and a large population size, so it is listed as a species of Least Concern by BirdLife International; however, the population in Europe is decreasing and its conservation status is uncertain.
The researchers set up their long-term study site in the wetlands near Kautokeino, Finnmark in northern Norway, focusing on the European subspecies. Finnmark is situated at the northernmost part of continental Europe, where the Norwegian coastline swings eastward and "East meets West" in terms of geography, culture, and the natural environment.3
Though national bird surveys take place in this region, there are few records of nesting Broad-billed Sandpipers and no demographic data from breeding populations. Traditional survey methods like counting all birds seen or heard in a standard spot (point counts) or walking in a straight line (line transects) tend to overlook the presence of these camouflaged and secretive birds. 4
To remedy this problem, Rae and colleagues began to collect preliminary data in 1993 in order to develop a method to find and study these birds. As expected, nests and incubating birds were difficult to locate. Not only are Broad-billed Sandpipers secretive and solitary, they also “sit tightly,” which means that they are not easily startled (flushed) from their nests when disturbed. Some birds sat tight on their nests even when a person was standing over them. Therefore, each area of mire was searched by walking over it in a meandering route (in contrast to a line transect) to cover all potentially suitable nesting habitat
Once a study area was established, the researchers found as many birds and nests as possible, though some nests had to be monitored from a distance of several metres because they could not be reached safely for the observer or the nest contents. Starting in 1995, Rae and colleagues began to capture incubating adults in nests that could be approached, by laying a mist net over the nest when the adult was sitting on eggs or chicks. The researchers did not trap adults on days with rain or high winds that could chill the eggs while the parent was off the nest and did not observe any cases of nest desertion due to catching birds. Once a bird was captured, aspects of the bird’s body size (biometrics) were measured and the bird was marked with a numbered metal ring and a unique combination of colour rings. Colour-ringing allowed the birds to be recognized (re-sighted) when surveys were conducted in later years, creating encounter histories for each individual bird. Within the encounter history, each year was coded as 1 = captured or re-sighted on the study area, or 0 = not detected during the breeding season.
[caption id="attachment_16697" align="aligncenter" width="330"]
Well camouflaged and colour ringed Broad-billed Sandpiper. (photo: Stuart Rae)[/caption]
The researchers used this study protocol every year from 1995-2019 to survey 10-14 days in the 3-week period between 15 June and 8 July. From 2000-2019, they further mapped local conditions around the nest sites (in later years using GPS coordinates) so that the same areas could be checked in subsequent years to locate pairs reusing the same location. From 2009-2019, they conducted intensive monitoring with experienced observers returning to all sites two or more times during the incubation period to estimate nest survival.
All those years of fieldwork paid off. Rae and colleagues found a total of 173 Broad-billed Sandpiper nests from 2000-2019, with an average of 8 per year, but varying between 2-16. Nests were typically set in a shallow depression (scrape) on a tussock (tuft) of vegetation or mossy hummock and lined with dry dead sedge. All of the nests were located in or on the edge of floating vegetation within the mires and only 5-10 cm above the water level. No other bird species was found nesting in this way or in these habitats. The birds were also very faithful to their nest site. Of the breeding birds that returned in subsequent years, 97% nested in the same mire and many pairs reused the same nest scrape.
[caption id="attachment_16696" align="aligncenter" width="330"]
Broad-billed Sandpiper nest. (photo: Stuart Rae)[/caption]
The average date for egg laying in years 2009-2019 was 10 June and varied between 1-24 June. Rae and colleagues were able to check the contents of 156 nests and found that 94% of these had four eggs, which is typical in shorebirds. They were further able to monitor the fate of 91 nests and recorded six losses due to flooding, one to predation and one from an unknown cause. Like most shorebird species, the males mainly took care of hatched young. The strategy of nesting on floating vegetation resulted in high nest success and low predation rates but left the nests vulnerable to flooding. Nest placement has conservation implications, especially if rainstorms fueled by climate change cause water levels to rise rapidly, threatening breeding success.
Rae and colleagues ringed and re-sighted 119 Broad-billed Sandpipers during the breeding seasons of 1995-2019. They found annual survival rates that were typical for small-bodied waders. Estimated survival rates did not differ between the sexes, but were lower among first-year than older birds, and highest among previously marked birds that had returned to the study site at least once. Biometric measurements of body size showed that, like in most species of shorebirds, females are larger than males, and that in Broad-billed Sandpipers the difference in size is greatest for bill length. Bill length affects feeding behaviour (pecking and probing for food) and in other shorebird species, this sometimes leads to males and females using different habitats and sometimes even different latitudes in the non-breeding season. Testing whether this might also be true for Broad-billed Sandpipers will require studies of feeding ecology on the non-breeding grounds.
Finally, the researchers captured three birds that had been caught and ringed elsewhere during migration (foreign recaptures). They were able to compare biometric measurements from these birds with similar data from birds breeding in the study site. These data suggested that birds breeding in Norway are part of the same population as birds stopping in the Sivash in eastern Europe during spring migration.5
The stopover area in the Sivash is located in the contested Crimean Peninsula. When this study began, Crimea was part of Ukraine and early fieldwork in both Norway and Sivash were underway. Two decades later in 2014, while the work in the breeding areas continued, Russia annexed the Crimea. This past year (2022), the Sivash is again in the middle of a war zone and one wonders about the fate of the birds, and of colleagues on both sides of the conflict.
The Sivash is not the only part of the Broad-billed Sandpiper flyway under threat. The researchers point out that poorly-studied nonbreeding habitats are also vulnerable to expanding human development. Future work will focus on tracking birds with geolocators, tiny tags that record ambient light level (solar irradiance) to determine the bird’s location. The tracking tags will allow researchers to gather better data on which habitats are critical in the nonbreeding range and might even allow data collection to continue when a site becomes inaccessible for on-the-ground study.
Thirty years is a long time. The internet rose, the Twin Towers in New York fell, wars began and ceased, and through it all these researchers walked carefully through the mires of northern Norway studying small sandpipers with short legs and strange bills. Their persistence and long-standing international cooperation provide more than just data about a poorly-studied bird species. In an increasingly fast-paced and divided world, this type of collaboration provides hope.
1 Rae, R, S Rae, B. K. Sandercock & D. P. Whitfield.
2022. The breeding ecology of Broad-billed Sandpipers in northern Norway
. Wader Study 129: 183–189.
2 Sandercock, B. K., R. Rae, S Rae, & D. P. Whitfield
. 2022. Sexual size dimorphism, disassortative pairing, and annual survival of Broad-billed Sandpipers in northern Norway
. Wader Study 129: 194–206.
. (2022, December 19). In Wikipedia
4 Hildén, O.
1981. Sources of error involved in the Finnish line-transect method
. Studies in Avian Biology
5 Verkuil, Y., T.M. Van der Have, J. Van der Winden, G.O. Keijl, P.S. Ruiters, A. Koolhaas, A. Dekinga & Chernichko, II
. 2006. Fast fuelling but light flight in Broad-billed Sandpipers Limicola falcinellus: stopover ecology at a final take-off site in spring (Sivash, Ukraine)
of this article
by Deborah Buehler originally published in Wader Study 129(3) Spotlight: A 30-year effort to study an elusive bird The ground gives beneath your feet and you know you have to stop. The wetland surrounding you is also known as a mire, a word that gives fitting connotations of sinking and getting stuck. You look at the bird through binoculars, not daring to go further. It is a small sandpiper with short legs and a long, broad bill with a downturned tip. The English name for this bird is, aptly,
The 2023 annual conference will be held at the Wadden Sea island of Sylt, Germany.
For more information, please consult the conference webpage:
The 2023 annual conference will be held at the Wadden Sea island of Sylt, Germany. For more information, please consult the conference webpage:
by Deborah Buehler originally published in Wader Study 129(2)
Migrant birds move to get what they need.
Shorebird migration to exploit seasonally fluctuating resources has been studied for years and researchers have mapped globe-spanning networks of places where birds reproduce at breeding areas, refuel at stopover sites, and spend the non-breeding season at wintering areas. Still, new sites of importance continue to be found and growing datasets compiling bird sightings over decades are integral to this work. Even within a site, migrants move to exploit resources, and much remains to be discovered at these smaller geographic and shorter-time scales.
In this issue of Wader Study
, two papers examine migrant movements on opposite sides of the Atlantic and at different scales. Both highlight the overlooked significance of relatively small sites for the health of shorebirds along a larger flyway. Mary Pelton, Sara Padula and colleagues document the importance of the Kiawah and Seabrook islands in South Carolina, USA using surveys and modelling to provide population estimates for Red Knots, Calidris canutus rufa
Clément Jourdan and colleagues use GPS telemetry to analyse the movements and behaviour of wintering Black-tailed Godwits Limosa limosa islandica
in France and describe the birds’ use of wetlands over different temporal scales.2
In South Carolina, the researchers focused on a subspecies of Red Knot. Rufa
knots are listed as threatened in both Canada and the United States due to an 85% population decline over the past few decades. The researchers’ goal was to estimate the number of rufa
knots using a 24-km stretch of sandy beach in the Kiawah-Seabrook Island complex (hereafter KSI) and to further understand where they came from, where they were going, and whether some birds used the site throughout the non-breeding season.
[caption id="attachment_16474" align="aligncenter" width="700"]
Scanning for colour-marked birds during surveys (photo: Mary Margaret Pelton)[/caption]
To do this, they conducted on-the-ground surveys between 19 February and 20 May 2021. Prior to this, they also deployed geolocators on birds captured at the site between April 2015 and May 2016. Geolocators periodically record ambient light level (solar irradiance) to determine location; however, the bird needs to be recaptured to download the data. Although a total of 33 geolocators were deployed, only three were retrieved as part of this study.
When shorebirds are captured in North and South America, they are marked with flags consisting of a unique alphanumeric code. Marking follows the Pan American Shorebird Group protocol,3
and flags are colour coded to the area the bird was first marked; for example, Canada (white), the United States (green), Argentina (orange). When the bird is seen again, researchers know at a glance where the bird was first marked and can identify the individual by the code. In their surveys, the researchers in South Carolina recorded the presence of birds that had been previously marked, and they sometimes saw the same birds multiple times over the season. This is called resighting. They also estimated the ratio of marked to unmarked birds. This information allowed them to use statistical models to estimate the number of birds passing through the area (passage population) and how long they stayed (stopover duration).
KSI lies south of Delaware Bay, which has historically been regarded as the last steppingstone for birds migrating from further south to refuel before departing for their Arctic breeding grounds. However, mounting evidence in the past decade shows that birds likely use a suite of stopover sites, not Delaware Bay alone. Because shorebird marking has been standardized in the Americas since the mid-1980s, the researchers had access to an online database, www.bandedbirds.org
, containing decades of data. Using this resource, they analysed previous capture and resighting data for all of the 217 uniquely flagged birds they resighted during their 13-week study. This work revealed that the birds had accessed a network of more than 70 sites spanning Texas to Florida to Massachusetts in the USA, as well as Ontario (James Bay) and Quebec in Canada. Results from the three geolocator-carrying birds also indicated that Delaware Bay was not be the only place to rest before leaving for the Arctic. All three birds skipped Delaware Bay after stopping in South Carolina.
The researchers also found evidence that rufa
knots might be using KSI for overwintering as well as stopover. First, their surveys indicated an estimated ~2,400 birds present at KSI as early as 19 Feb, and many were subsequently observed again in May, suggesting that they had stayed throughout the winter. Second, as the season progressed the number of birds increased, indicating an influx of new birds from further south. Thus, KSI likely supports two groups of rufa
knots: those that spend the non-breeding season there, and those that migrate through, using the site as a stopover. The idea that distinct groups might exist within the rufa
subspecies is not new. Major nonbreeding clusters of rufa
knots have been found in the south-eastern USA (Florida and Texas), north-central Brazil, and Tierra del Fuego. Genetic work by Yvonne Verkuil and colleagues described evidence that suggests that these groups might also be genetically different.4
Importantly, the statistical modelling indicated a minimum of 17,000 rufa
Red Knots (over 40% of the total population) used KSI during their study period. Combined with other findings, this provides ample evidence that KSI is important along the flyway as a stopover and overwintering site for rufa
Red Knots. The site is also important for other shorebird species. Another recent study reported a nocturnal roost supporting nearly half of the Atlantic Flyway population of Hudsonian Whimbrel Numenius hudsonicus
on Deveaux Bank, right next to KSI.5
The authors recommend the nomination of KSI and neighbouring Deveaux Bank as a Site of Hemispheric Importance in the Western Hemisphere Shorebird Reserve Network.
On the other side of the Atlantic, in France, Clément Jourdan and colleagues were focused on another long-distance migrant, the Black-tailed Godwit. Unlike rufa
knots, the population of the islandica
godwit subspecies has been increasing for several decades. They are omnivorous and able to exploit multiple habitats, making them ideal for studying habitat choice in wintering sites over different temporal scales. The researchers worked on the French Atlantic coast focusing on wintering habitats within a 6,000 km2
area including the Loire Estuary, Bourgneuf Bay, the Vendée Coast, and the Pertuis Charentais area, where most of France’s Black-tailed Godwits spend the non-breeding season.
The goal was to describe how birds used the space at a single wintering site by identifying the most-used habitat for each individual on each monitoring day, then investigating when birds changed their daily most-used habitat over the season. The researchers also studied habitat choice across the span of a single day (within
days) to describe habitat shifts over 24-hour periods. They used an existing system to classify the habitat types and focused on ‘cropping systems’ (i.e., arable land), ‘inland marshes’, ‘coastal marshes’, ‘saltpans’, ‘bare mudflats’ and ‘other habitats’ (i.e., land not normally used by godwits) for this study.
The researchers used GPS telemetry to track the birds’ movements. To install the GPS tags, birds were captured at night with mist nets set on their high tide roosts between November 2016 and October 2018. All birds were weighed, measured, and their age and sex were determined. They were then marked with a metal ring and a unique colour ring combination. GPS tags were fitted to the heaviest individuals only, so as not to exceed 3% of the bird’s body mass. The GPS tags recorded location every thirty minutes or so and with an accuracy of plus or minus ten meters. The researchers only used data from godwits with at least one month of wintering data on the Central French Atlantic coast for this study. Ten birds fit these criteria and were monitored from 3 March 2016 to 24 April 2020.
[caption id="attachment_16475" align="aligncenter" width="700"]
Deploying a GPS tag (photo: Thierry Guyot)[/caption]
At the level of habitat choice over a season, Jourdan and colleagues found that most islandica
godwits used intertidal areas from early to mid-winter, then moved to inland marshes just before the spring migration period. This finding supports previous work which has shown this shift, with authors suggesting that it occurs in response to seasonal prey depletion on intertidal habitats. The birds move inland to habitats to follow the abundance of food.
At the level of habitat shifts within a day, habitat use in coastal areas depended on the tide. Birds fed in intertidal habitats like ‘bare mudflats’ at low tide and used the coastal marshes to rest (roost) at high tide regardless of time of day. When using inland habitats, like ‘inland marshes’, they were often observed roosting during the day, with feeding activity occurring mainly at night. One interesting observation was the birds’ use of hunting ponds. Hunters attract ducks to these ponds and hunt them at night between early August and late January. During the hunting season, the researchers found that shorebirds mainly exploited these ponds during the day, but after the hunt closed, the birds used the ‘hunting ponds’ both day and night.
Migrant birds move around – a lot – and they do this at varying space and time scales. Pelton, Padula and colleagues explored this at the level of a chain of stopover and wintering sites on the Atlantic coast of the United States. On the other side of the ocean, Jourdan and colleagues looked at how birds shift between different habitat types within a wintering area. Half a world away in India, researchers are starting to gather data for what will hopefully be another long standing dataset of captures and resightings.6
These studies show that there is much yet to discover about migrant shorebirds in terms of where they go, when they go and why those places they stop at are important.
1 Pelton, M.M., S. R. Padula, J. Garcia-Walther, M. Andrews, R. Mercer, R. Porter, F. Sanders, J. Thibault, N. R. Senner & J. A. Linscott
. 2022. Kiawah and Seabrook islands are a critical site for the rufa Red Knot (Calidris canutus rufa)
. Wader Study 129: 105–118.
2 Jourdan, C., J. Fort, F. Robin, D. Pinaud, P. Delaporte, D. Desmots, A. Gentric, P. Lagrange, J. Gernigon, L. Jomat, P. Rousseau & P. Bocher.
2022. Combination of marine and freshwater artificial habitats provide wintering Black-tailed Godwits with landscape supplementation
. Wader Study 129: 86–99.
3 Pan American Shorebird Group.
2016. Pan American Shorebird Program Shorebird Marking Protocol. https://www.shorebirdplan.org/wp-content/uploads/2016/08/PASP-Marking-Protocol-April-2016.pdf
4 Verkuil, Y.I., E. Tavares, P.M. González, K. Choffe, O. Haddrath, M. Peck, L.J. Niles, A.J. Baker, T. Piersma & J.R. Conklin.
2021. Genetic structure in the nonbreeding range of rufa Red Knots suggests distinct Arctic breeding populations
. Ornithological Applications
5 Sanders, F.J., M.C. Handmaker, A.S. Johnson & N.R. Senner
. 2021. Nocturnal roost on South Carolina coast supports nearly half of Atlantic coast population of Hudsonian Whimbrel Numenius hudsonicus during northward migration
. Wader Study
6 Panigrahi, M., P. Sathiyaselvam & T. Katti.
2022. Additions to ring resightings and recoveries of migratory shorebirds at Marine National Park and Sanctuary, Gujarat, India
. Wader Study 129: 148–150.
of this article
Featured image: Black-tailed Godwit, March 2020 France, (c)Fabrice Cahez.
by Deborah Buehler originally published in Wader Study 129(2) Migrant birds move to get what they need. Shorebird migration to exploit seasonally fluctuating resources has been studied for years and researchers have mapped globe-spanning networks of places where birds reproduce at breeding areas, refuel at stopover sites, and spend the non-breeding season at wintering areas. Still, new sites of importance continue to be found and growing datasets compiling bird sightings over decades are
The 21st April was World Curlew Day and it was really great to see the conservation efforts being celebrated and shared in the media to recognise the plight of this species but also highlighting the international collaborations that will be needed to save this species. I have also been watching with great interest the live news about the migration of the curlews that have been tagged on the Wash estuary in the UK this year and as ever, receiving many sightings of our black-tailed godwits as they return from west Africa through Europe and onto England to breed.
What this highlights to me is that the waders we all love have absolutely no idea about the international boundaries that they may cross as they move to and from their breeding and wintering areas. This causes me to reflect on those species which may be migrating through or, are resident in countries affected by the war in Ukraine. I have recently read a rather sobering document which was outlining the potential impacts of the war on birds in Ukraine which is home to 434 species, 18 globally threatened birds, 19 species for which the country hosts more than 15% of the European population and 141 Important Bird Areas covering 2.5 million hectares. The predictions of large-scale habitat loss and degradation, local extinctions, increased disturbance, pollution and hunting were stark but at the same time, I was inspired by the fact that amidst the war, conservationists in Ukraine are already thinking about the future needs of their species in their country and the role that nature will play in healing their country and people. I just want to say to all of our Wader Study group members affected by the war, that we are thinking about you, we hope you are all safe and once this war is over, which we hope will be very soon, our thoughts can turn to how we use our international networks and collaborations to help the global conservation effort that will be required.
Chair of the International Wader Study Group
The 21st April was World Curlew Day and it was really great to see the conservation efforts being celebrated and shared in the media to recognise the plight of this species but also highlighting the international collaborations that will be needed to save this species. I have also been watching with great interest the live news about the migration of the curlews that have been tagged on the Wash estuary in the UK this year and as ever, receiving many sightings of our black-tailed godwits as they
By Deborah Buehler
People catch shorebirds for many reasons; some for research and study, others as a supplemental food source. The Caribbean coast is rich in birdlife, and all along this coast, including the islands and the northern shores of South America, shorebirds have been hunted for food. This cultural tradition has gone on for centuries. For some people, it is a practical way to make ends meet, but others worry about whether the hunting affects shorebird populations. How many birds are currently being hunted? Are the numbers high enough to affect shorebirds populations?
These are big questions, and they cannot be answered in a single study. However, a first step is understanding the extent of shorebird hunting in any given location. Guyana is a country where shorebird hunting is legal and there are no limits on the number of birds that can be harvested. Though the country does have laws that protect its wild birds, the Wild Birds Protection Act focuses on resident species and does not provide protections for migratory shorebirds. What is not known is when and to what extent people exercise their right to hunt shorebirds and whether the hunting is intense enough to impact shorebird populations.
In this issue of Wader Study
, Brad Andres and colleagues assess the current prevalence and magnitude of hunting and selling migratory shorebirds along the coast of Guyana.1
They also compare species composition and harvest levels to other jurisdictions in the Caribbean and northern South America to understand the larger context of shorebird hunting throughout the region.
[caption id="attachment_16006" align="aligncenter" width="330"] Coastline of East Berbice, Guyana. (photo: Leon Moore)
Guyana is a tropical country located in South America between Venezuela and Suriname. Its coastal plain occupies only about 10% of the country’s area, yet 90% of its population lives there. A small portion of this population hunts shorebirds as part of the bounty the coast provides. The primary method for hunting shorebirds on the Guyanese coast is known locally as “shocking”, and the authors described its practitioners as “shockers”. As part of her 2005 Bachelor’s thesis research, Annalise Bayney confirmed the continued use of this method in the new millennium and provided a description of how shocking is conducted.2
A 12- to 15-meter length of stiff wire is attached to a short stick inserted into the sand or mud. As a flock of birds skims the surface of the shore, the wire is pulled taut horizontally, cutting into the flock. The tension of the wire kills the birds, sometimes removing appendages in the process.
[caption id="attachment_16007" align="aligncenter" width="330"] Hunting using the “shocking” technique. A vertical stick is used to pull a horizontal wire taunt as birds take off from the mudflat. (photo: Leon Moore)
Andres and colleagues returned to the 55 sites that Bayney surveyed in her earlier study and added five additional sites, to document continued shorebird hunting over the last two decades. Between August–October 2017 and October–November 2018, they visited 60 sites. At each site, they assessed potential shorebird habitat (e.g., mudflats/sand flats versus mangroves) and, if the site was suitable, counted the number of shorebirds present and the species composition of the flocks. The researchers also searched for evidence of hunting. If they didn’t see hunting directly, they asked local community members about their knowledge of current hunting activity in the area.
The researchers returned in 2020, to focus on sites where they had documented hunting in 2017 and 2018. They visited sites every two weeks on Fridays and weekends between late August and early November. The choice of time of the week was intentional. Markets, where shorebirds might be sold, operate on weekends. During the 2020 field season, the researchers interviewed shorebird hunters at two sites and vendors at a local market. They used a questionnaire adapted from one used previously to interview shorebird harvesters in Brazil, French Guiana, and Suriname. All interviewees provided informed consent to be interviewed, remained anonymous, and were interviewed by Guyanese nationals.
To analyse and extrapolate the interview data, the researchers employed a statistical method – Bayesian hierarchical modelling – that can integrate observed data and uncertainty across several different levels of observation. This analysis allowed them to estimate the number of active hunting groups and the number of birds killed at the study sites on days when the researchers were not physically there to make observations.
Results indicated that only 28 of the 60 sites visited by the researchers still contained habitat suitable for shorebirds. Of the sites where suitable habitat was still present, the researchers focused on the 19 sites where the most shorebirds were found, to study species composition and temporal trends. They detected 18 species of shorebird. Small Calidris
sandpipers made up 92.6% of all shorebirds counted and the majority of these were Semipalmated Sandpipers Calidris pusilla
. Other species that made up more than 1% of the total count were Tringa
sandpipers (mainly Lesser Yellowlegs T. flavipes
) and Semipalmated Plovers Charadrius semipalmatus
In terms of hunting, the shocking method was detected at six of the 60 sites visited in 2017–2018, and shooting, as an alternative method of hunting, was also observed at one of these six sites. The researchers also recorded shocking in an abandoned rice field, now used to farm shrimp, where flooded fields attract resting shorebirds during high tide. This site was not one of the six study sites where shocking was detected, but rather an additional and opportunistic observation, and the only site where shorebirds were hunted away from the shoreline. When surveying the markets, the researchers found shorebirds for sale at the Mon Repos and Port Mourant markets in 2017– 2018, with up to 1,000 shorebirds being sold on one occasion. In 2020, the researchers observed shocking on a regular basis at two sites and, at much lower levels than found in 2017–2018, at a third site. They also found shorebirds for sale at the Port Mourant market.
These results suggest that shorebird hunting decreased between the surveys done in 2005 and this current study. In Bayney’s 2005 study, hunting was recorded at 40 of 55 sites (73%) compared to only six of 60 (10%) of sites in 2017–2018. However, a large part of this decrease is likely due to the fact that the Guyanese coastline changed dramatically in the last decades, greatly decreasing the amount of suitable shorebird habitat. More than half (53%) of the sites visited in 2017–2018 no longer provided suitable habitat for shorebirds due to mangrove forestation, erosion, or sand deposition. What is relevant then, is the hunting recorded at sites where shorebird habitat was available, hence six of 28 sites (21%) in 2017–2018. Even taking this into account, there is still a decrease, and the authors point out that socio-economic or cultural factors beyond the scope of their study might have contributed. However, they warn that direct comparison across time is tenuous because survey methods differed between their study and Bayney’s. What they did say with certainty, is that shorebird hunting has not increased in Guyana in the last two decades.
In addition to shorebird counts and recording instances of hunting, the researchers interviewed 10 shockers in 2020. All of those interviewed said that they only harvested shorebirds during fall migration and used the shorebirds they killed for personal consumption. Some additionally said that they sold shorebirds directly to local restaurants or to other people in the community, but none said that they supplied shorebirds to commercial vendors at the Port Mourant market. Nevertheless, in 2020 the researchers found at least 13 species of shorebird for sale at Port Mourant.
[caption id="attachment_16008" align="aligncenter" width="330"] Shorebirds for sale at the Port Mourant market. (photos: Leon Moore)
The species for sale reflected the composition of species found in the counts conducted along the coast. The birds for sale were mainly small Calidris
sandpipers, but also larger species such as Greater Yellowlegs Tringa melanoleuca
, Black-bellied Plovers Pluvialis squatarola
, and Whimbrels Numenius phaeopus
. This makes sense since, as a hunting method, shocking is effective for small and large shorebirds alike.
Given that the shockers interviewed in 2020 did not sell shorebirds to the markets, yet the researchers found shorebirds for sale at the market in abundance, the field study clearly could not measure all instances of shorebird hunting or selling. Models, however, were able to extrapolate the information gathered during interviews and to estimate that approximately 37,000 shorebirds were harvested at two sites and sold in one market during the 2020 study period. Given the limited scale of the study in 2020, the total harvest along Guyana’s entire coast was undoubtedly greater.
The magnitude of harvest in Guyana is second only to Suriname and exceeds that of all Caribbean islands combined. 3
The lack of a national policy to regulate this harvest is a challenge to sustainable hunting in Guyana and ultimately throughout the region. This broader context is important because each country is a link in the chain that is a migrant’s journey. Migrating shorebirds are subject to the policies of all of the countries they visit, sequentially. Watts and Turin provided a synthesis of hunting policies across the Western Atlantic Flyway.4
Even if each country sets sustainable limits, the cumulative number of individuals killed along an entire migratory route – the collective harvest – might be too high.5
Andres and colleagues show that shorebird hunting in Guyana is significant and may account for a substantial portion of mortality from hunting in the Caribbean and northern South America. Laws that limit or ban shorebird hunting would help to sustain shorebird populations; however, people have reasons for hunting shorebirds. What would the social and financial consequences be for local people? Though the shocking method for hunting is lethal, the researchers found strings of live birds sold by vendors in the market. Those birds were likely netted – a non-lethal way of catching birds. Can hunting skills be repurposed in a way that saves birds, helps science, and still contributes to the livelihood of locals? This study does not answer these questions, and the authors acknowledge that more research is needed to understand the social aspects of shorebird hunting and its economic impact. Science builds knowledge, study after study, and for shorebird conservation to work, it must respect the needs of local hunters, vendors and conservationists.
- Andres, B.A., L. Moore, A.R. Cox, B. Frei & C. Roy. 2022. A preliminary assessment of shorebird harvest in coastal Guyana. Wader Study 129(1): 39–47.
- Bayney, A. 2005. The effect of birding on local and migrant waterfowl populations along the coast of Guyana. Bachelor’s Thesis, University of Guyana, Guyana.
- AFSI Harvest Working Group. 2020. Actions for the Atlantic Flyway Shorebird Initiative’s Shorebird Harvest Working Group 2020–2025. U.S. Fish & Wildlife Service, Migratory Bird Program, Falls Church, VA, USA.
- Watts, B. D. & C. Turrin. 2016. Assessing Hunting Policies for Migratory Shorebirds throughout the Western Hemisphere. Wader Study 123(1): 6-15.
- Watts, B. D., E. T. Reed & C. Turrin. 2015. Estimating sustainable mortality limits for shorebirds using the Western Atlantic Flyway. Wader Study 122(1): 37–53.
of this article
Featured image: Semipalmated Sandpiper, Nome - Alska June 2017. ©
Mick Thompson/Eastside Audubon.
By Deborah Buehler People catch shorebirds for many reasons; some for research and study, others as a supplemental food source. The Caribbean coast is rich in birdlife, and all along this coast, including the islands and the northern shores of South America, shorebirds have been hunted for food. This cultural tradition has gone on for centuries. For some people, it is a practical way to make ends meet, but others worry about whether the hunting affects shorebird populations. How many birds are