WaderTales blogs in 2020

Around the world in sixteen blogs

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

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

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

A Scottish trio

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

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

Nesting waders

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

Black-tailed Godwits

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

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

Behaviour

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

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

Book reviews

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

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

Previous summaries

WaderTales blogs in 2019

WaderTales blogs in 2018

WaderTales blogs in 2017

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research. Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.The intention is to add one or two new blogs each month. You can sign up to receive an e-mail notification when a new one is published. There’s a full list of blogs here.

WaderTales wins BTO Award

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

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

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

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

Dilys Breese

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

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

WaderTales and the BTO

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

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

The Dilys Breese medal

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

Graham Appleton

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

The First Five Years

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

There are six sections:

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

The most popular stories

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

It all started in Iceland

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

Migration

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

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

A focus on individuals

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

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

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

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

Thoughts about moult

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

Conservation issues

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

Acknowledgements

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

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

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

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

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

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

Graham Appleton

Here’s a link to the full WaderTales catalogue

WaderTales blogs in 2019

Nineteen new WaderTales blogs were published during 2019. Click on a link in bold to read an individual blog.

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Ringed Plovers often have time to nest again if the first clutch is lost

Over 25,000 people, representing 130 countries, visited the WaderTales website during 2019.

  • The most widely-read blog was Ireland’s Curlew Crisis, reflecting the international concern for the species and the culew family as a whole.
  • It is great that the next most popular blog is Managing water for waders, as this is such a positive story about how farmers, conservation organisations and statutory agencies can work together to deliver better habitat for breeding waders and an improved water supply for farmers.
  • In third place is Sixty years of Wash waders which describes six decades of scientific outputs of the Wash Wader Ringing Group. The WWRG’s founder, Clive Minton, died in tragic circumstances just a couple of months later and there are some lovely tributes here, on the International Wader Study Group website.

Migration

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The distinctive white under-wing of a Steppe Whimbrel

The migration blogs cover a wide range of species:

  • Generational Change uses colour-ring sightings to explore how Black-tailed Godwit populations have changed in distribution and migratory timing.
  • Whimbrel: time to leave summarises a paper about the consistencies and variability of annual migration patterns of individual Whimbrel.
  • Red Knot pay the price for being fussy eaters discusses the reliance of Delaware Bay birds on the unpredictable annual supply of horseshoe crab eggs. Why are Ruddy Turnstones better able to cope in a changing world?
  • Not-so-Common Sandpipers mixes information about migration with a review of Common & Spotted Sandpipers by Phil Holland.
  • Travel advice for Sanderling summarises research to understand the pros & cons of spending the non-breeding season in widely different locations. Birds in equatorial Africa do far less well than those in England and Namibia.
  • In search of Steppe Whimbrel summarises a paper about two very special individual Whimbrel. Will this knowledge help to rescue a subspecies?

Breeding waders

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Redshanks need long grass in which to hide their nests

There is bad news for Curlew and Redshank, some interesting information about the effects of ticks on chicks and an important stock-take of Fennoscandia’s breeding waders.

  • Redshank – the ‘warden of the marsh’ focuses on Redshank that breed on saltmarshes and the agricultural subsidies that help to fund their conservation.
  • From local warming to range expansion explores the role of climate warming in fuelling the century-long range expansion of Iceland’s Black-tailed Godwit population.
  • Ireland’s Curlew Crisis focuses on the nationwide breeding survey between 2015 and 2017, which revealed a 96% decline in the number of pairs in the previous 30 years.
  • Chicks and Ticks reviews a study of the effects of ticks on the survival probability of Golden Plover chicks.
  • Fennoscandian wader factory summarises analyses of breeding wader numbers in Finland, Sweden and Norway over the period 2006 to 2018.
  • Managing water for waders celebrates work to reduce flooding, store fresh water for farmers and create habitat for breeding waders.
  • Time to nest again? asks how much of the advantage of being an early migrant could be associated with having an option to nest again, if the first attempt fails.

Winter waders 

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Winter numbers of Oystercatcher and Knot have declined in Britain and Ireland

The Green Sandpiper blog reveals unpublished information about territoriality. The other two blogs in this section summarise population estimates of waders in Great Britain and Ireland, based on new papers in British Birds and Irish Birds.

  • Winter territories of Green Sandpipers includes unpublished information from southern England, where survival is affected by the severity of winters.
  • Do population estimates matter? is inspired by the waders section of Population estimates of wintering waterbirds in Great Britain, based on data from the Wetland Bird Survey and the Non-estuarine Waterbirds Survey.
  • Ireland’s wintering waders complements the above blog, providing information from I-WeBS and WeBS for the island of Ireland and set in a European context.

The others!

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Adding colour rings and individual flags to Grey Plover

One of the aims of these blogs is to engage people in projects that are in need of volunteers or other forms of public engagement – hence the Northern Ireland blog. The other two articles celebrate sixty years of The Wash Wader Ringing Group and share concerns about a new airport for Lisbon, to be built right next to the Tagus/Tejo Estuary.

  • The Waders of Northern Ireland was written as a promotional tool for a 2019 breeding survey but covers wintering and passage species too.
  • Sixty years of Wash waders celebrates the longest-running wader-ringing project in the UK  (and the world?), by summarising six decades of migration research.
  • Tagus estuary: for birds or planes? What could go wrong if an international airport is built right next to an estuary that is important to Black-tailed Godwits?

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Vast flocks of Black-tailed Godwit gather in the Tagus Estuary in February

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research. Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.The intention is to add one or two new blogs each month. You can sign up to receive an e-mail notification when a new one is published. Full list of blogs here.


GFA in IcelandGraham (@grahamfappleton) has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland.  He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.

Migration blogs on WaderTales

wwrg GKHere’s a selection of over thirty WaderTales blogs that celebrate the wonder of shorebird migration. The focus is mainly on the East Atlantic Flyway, because that’s where I learnt about waders, but there’s a blog about the shocking drop in the numbers of waders that use the Yellow Sea migration route, an amazing story about a shorebird that links Egypt with the far east of Arctic Russia and some thoughts about teenage waders, focused on Hudsonian Godwits in Chile. 

Multi-species blogs

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Oystercatcher

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Sociable Lapwing

  • Following Sociable Lapwing describes how geolocators have revealed two distinct migration routes and identified key stopover sites. This is vital information for conservationists, keen to learn more about unsustainable hunting practices that are threatening the viability of this endangered species.

Ringed Plover

  • RP geolocatorWell-travelled Ringed Plovers from Chukotka in north-east Russia spend the winter in Somalia, Egypt, the Red Sea & the Persian Gulf. In Chukotka these Ringed Plovers breed alongside Buff-breasted Sandpipers heading for South America, Knot that will migrate to Australia and Spoon-billed Sandpipers that may migrate to Bangladesh. It’s a small world!

Grey Plover

  • Plovers from the north is a blog about the global migration patterns of Grey Plovers (Black-bellied Plovers), with an Australian focus.

Dotterel

  • Scotland’s Dotterel: still hanging on. The fate of Dotterel that breed on the plateaux in Scotland’s highest mountains may be more closely linked to changes taking place in North Africa than to warming conditions in their nesting areas.

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Whimbrel

  • Whimbrels on the move summarises a paper about the movements of Icelandic, ringed Whimbrel, using ringing and colour-ringing data.
  • Iceland to Africa, non-stop discusses the speed of migration of Icelandic Whimbrel in spring and autumn.
  • Whimbrel: time to leave summarises a paper about the consistencies and variability of annual migration patterns of individual Whimbrel.
  • A Rhapsody of Whimbrel asks whether Whimbrel use time and weather cues in their travel ‘planning’ and might their plans change during the course of their lives?
  • Winter conditions for Whimbrel looks for links between the conditions that individual Whimbrel experience in Africa and the subsequent breeding success in the Iceland.
  • In search of Steppe Whimbrel summarises a migration paper about two very special individual Whimbrel. Will this knowledge help to rescue a subspecies?

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Bar-tailed Godwit

DSCN1827Black-tailed Godwit

The individual movements and breeding season behaviour of Icelandic Black-tailed Godwits have been studied for twenty years. They have been supported by thousands of birdwatchers who report colour-ringed birds.

Hudsonian Godwit

  • Teenage waders is ostensibly about Hudsonian Godwits but raises general questions about the conservation of young shorebirds.

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Knot

  • Red Knot pay the price for being fussy eaters compares the fortunes of Knot and Turnstone that stop off in Delaware Bay. As they fatten up to travel to the Arctic, the inflexibility of Red Knot make them more prone to unpredictable food supplies (and climate change).

Sanderling

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

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Semipalmated Sandpiper

  • Gap years for sandpipers discusses the pros and cons of breeding every year. It is a long way from Peru to Alaskan and Canadian breeding grounds. There appears to be a trade off between migrating north in spring, to try to rear youngsters, and taking a gap-year. Staying in Peru increases the probability of survival, thereby securing more breeding attempts in future years.

Spoon-billed Sandpiper

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  • Spoon-billed Sandpipers: Track & Trace is another detective story. Spoon-billed Sandpipers are in big trouble, with an estimated population of just 660 birds, including youngsters. By satellite-tracking a small number of birds, an international research team has been able to identify new stop-over and wintering sites. This information will help to target efforts to protect habitats within key estuaries and to reduce hunting pressure.

Snipe & Jack Snipe

Common & Spotted Sandpiper

  • Not-so-Common Sandpipers mixes information about migration with a review of Common & Spotted Sandpipers by Phil Holland.

blog2 movementsGreen Sandpiper

  • Green Sandpipers and Geolocators summarises a Ringing & Migration paper about changing behaviour patterns in Green Sandpipers that wore geolocators to study their migratory journeys. See map alongside.

Spotted Redshank

  • Fewer Spotted Redshanks reviews migration patterns and changes in abundance of the species, in a British & Irish context.

Greenshank

  • Migration of Scottish Greenshank may seem tame when compared to the massive journeys made by birds that winter in Australia. Blog based on neat small-scale study.

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Here’s a link to the full list of WaderTales blogs. https://wadertales.wordpress.com/about/

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

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GFA in IcelandGraham (@grahamfappleton) has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland.  He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.

In search of Steppe Whimbrel

blog in flightIt’s unsurprising if you have not heard of a Steppe Whimbrel; the subspecies was declared extinct in 1994. In this context, a new paper in Wader Study, based on detailed studies of two birds that were found in Mozambique in 2016, adds immensely to our knowledge.

Bleak times for the Numeniini

The curlew family is facing huge pressures across the globe. Eskimo Curlew and Slender-billed Curlew are either extinct or close to extinction, with no confirmed sightings for 56 and 18 years, respectively. We are definitely losing species but are we losing diversity within individual species too – as suggested by the rarity of the Steppe Whimbrel and the fragmenting distribution of the Hudsonian Godwit? There is a lot of information about the current status of different populations and subspecies of the Numeniini  family in Why are we losing our large waders? a WaderTales blog about curlews, godwits and the Upland Sandpiper based on a review paper by James Pierce-Higgins and colleagues.

As a species, the Whimbrel is categorised as ‘of least concern’ but the ‘once extinct’ Steppe Whimbrel would be considered as ‘critically endangered’ if it were to be a species, rather than a subspecies.

Whimbrel are circumpolar in distribution and it is generally accepted that there are four subspecies:

  • phaeopus breed from Iceland through Scandinavia and into western Siberia; they spend the non-breeding season largely in western and southern Africa.
  • variegatus breed across the rest of north-eastern Russia and migrate to southeast Asia and Australia.
  • hudsonicus breed across northern Canada and Alaska and migrate to Latin America.
  • alboaxillaris are thought only to breed in the steppes of Russia and Kazakhstan, at the centre of the European land-mass, and to winter only in southeast Africa.

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First find (and identify) a Steppe Whimbrel

The fact that Steppe Whimbrel was considered to be extinct just 25 years ago gives a clue as to how hard it is to find one. Details about recent records are summarised in a new paper in Wader Study by Gary Allport and colleagues, that forms the basis of this WaderTales blog. Three breeding sites have been identified, holding a maximum of 19 breeding pairs, in total, and a maximum autumn count of 11 birds has been recorded on passage, on the shores of the Caspian Sea in 2010. The two birds that Gary found in Maputo, Mozambique in February 2016 are the first wintering records in Africa (or anywhere else) since 1965.

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The photographs above show that the two birds found at Maputo by Gary Allport of BirdLife International are different in several respects to the phaeopus with which they associated:blog on ground

  • Steppe Whimbrel are bigger
  • There are cleaner/paler in overall appearance
  • The rump is paler
  • They have white axillaries

For more information see Allport, G. & C. Cohen. 2016. Finding Steppe Whimbrel: discovery and identification in southern Africa. AfricanBirdlife 4: 48–54. If you come across what you think is a Steppe Whimbrel, possibly in eastern Africa during the non-breeding season, check for white under-wings and take as many pictures as possible!

blog in handAt the time of the discovery of the two Steppe Whimbrels, BirdLife had already got a strategy in place to deal with the unexpected appearance of a Slender-billed Curlew – ever hopeful that this species is not extinct. If seen in the non-breeding season, a bird was to be caught and satellite-tagged, in order to try to find its breeding area. The same procedures seemed appropriate for the Maputo Steppe Whimbrels and one bird was duly caught and tagged. That’s probably another story – anticipation – tension – concern for the bird’s safety – relief when it accepted its tag and behaved normally – and elation when data started coming in.

Local movements

blog photographerThe Maputo area, in which the two Steppe Whimbrel were found, comprises about 6 km of tidal muddy sand banks and flats. The area is heavily used by people, with zoned sections for various uses including traditional worship and tourism. The two Steppe Whimbrel were found by chance in February 2016, at the high tide roost on the upper beach. One was bigger than the other, suggesting a female and male. No other alboaxillaris were found in a larger population of 650 Whimbrel photo-identified in Maputo Bay. This paper talks about the discovery: Allport, G. 2017. Steppe Whimbrels Numenius phaeopus alboaxillaris at Maputo, Mozambique, in February–March 2016, with a review of the status of the taxon. Bulletin African Bird Club 24: 27–37.

The local movements of the two Steppe Whimbrel in Maputo Bay, Mozambique, were studied opportunistically from February to March 2016. Both birds were found to be part of a local sub-population of ca. 30 Whimbrel which held individual feeding territories on sandy shorelines. There are important details about behaviour and habitat-use in the Wader Study paper. The male was seen more frequently and predictably.  Knowledge of his movements made it possible to catch him, by dazzle-netting at night, on 6 March. Metal and colour-rings were added, together with a PTT satellite tag. A DNA sample proved that he was indeed a male.

The male was noticeably plump when caught, suggesting that he was already preparing for northward migration. Data gathered from the tag during the period before departure added valuable extra information about key feeding areas north of the main study area, where mangroves make it hard to observe birds.

Time to fly north

blog mapThe female Steppe Whimbrel was last seen in the Maputo area on 28 February 2016, and it is suggested that she may have left the areas on or shortly after this date. The last sighting of the male was on 24 March 2016 and, using information from his PTT satellite tag, the Mozambique team know that he started to migrate the next day. Although nearly a month after the possible departure of the female, this is still one month earlier than the onset of migration for the phaeopus subspecies. This is not unexpected; phaeopus birds are heading for higher latitudes than alboaxillaris, which breed in the heart of the Eurasian continent, in the steppes of Asia.

Upon leaving Mozambique, the tagged male headed over Tanzania before the scheduled transmission phase ended. At the start of the next recording period, the bird had travelled to the northern end of the Great Rift Valley in Ethiopia. He then turned in a more easterly route to the Somali coast. During the tag’s next ‘off phase’ he crossed the Gulf of Aden where he was picked up moving up and down the coast before settling on some salt-pans in the area of Little Aden.

The tagged bird made a 4,659-km journey in six days to Aden, Yemen and his migration route was consistent with the direction of travel for the known breeding areas of alboaxillaris. The track data are the first firm evidence of a long-suspected African transcontinental migration route for southeastern Afro-Palaearctic coastal waders.

blog tag mount

The tag was attached to the back of the Steppe Whimbrel. Feathers have been parted to show the  tag. After two months, the tag dropped off.

The tagged Steppe Whimbrel stayed in the Little Aden coastal area of Yemen until 10 May, when the pattern of fixes changed to a stationary location in the northwest side of the bay. This suggested that the tag had fallen off the bird, possibly floated across the bay on the prevailing southeast wind and then settled on the shoreline. Confirmation of the loss of the tag came on 14 August, when Gary Allport came across the same Steppe Whimbrel, wearing colour rings, back in Maputo. That must have been a great moment.

Key take-home messages

tweet 4If you are on the African shores of the Indian Ocean, in Africa’s Great Rift Valley or perhaps the coasts of western India or the Middle East, please check out any Whimbrel you see. Steppe Whimbrels live up to their names – look out for the white (albo) underwing (axillaris). Perhaps you will find the next Steppe Whimbrel and it will be in a location where capture is again possible. Maybe your bird will carry the next PTT transmitter for long enough to tell conservationists where to look for what must be a tiny population of breeding Steppe Whimbrel. Peter Ryan of the Percy Fitzpatrick Institute of African Ornithology (University of Cape Town), has recently secured funding from the Mohamed Bin Zayed Fund to tag Steppe Whimbrel. He and Gary are on the look-out for any birds that might be suitable for further study. 

blog in hand underwingOne of the great things about this tracking study is that it acts as a trial-run, should anyone find a Slender-billed Curlew or (even more unlikely) an Eskimo Curlew. We know that BirdLife scientists and their colleagues have the skills needed safely  to catch a rare, large wader and to maximise the amount of information that can be gathered about its migratory movements. Fingers crossed that it’s not too late to find out what is happening to other Steppe Whimbrel, or possibly even Slender-billed Curlew. Sadly, I think that we have to admit that the Eskimo Curlew is now almost certainly extinct.

Paper

Click on the paper details below to link to the Wader Study website. Full text is only available to members of the International Wader Study Group.

Allport, G.A., P.W. Atkinson, M. Carvalho, N.A. Clark & R.E. Green. Local site use and first northbound migration track of non-breeding Steppe Whimbrel Numenius phaeopus alboaxillaris (Lowe 1921). Wader Study 125(3). doi:10.18194/ws.00126

 

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GFA in Iceland

Graham (@grahamfappleton) has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland.  He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.

 

 

 

WaderTales blogs in 2018

RP no geolocatorThe amazing migrations of Ringed Plover, concerns about Spotted Redshank and lessons from Little Tern conservation …

just three of the highlights from WaderTales in 2018.

Seventeen new WaderTales blogs were published during the year, bringing the total so far to 65. There are three articles about Black-tailed Godwits (total now 16), two more focusing upon Icelandic research (total 8) and lots of new single-species and conservation-related tales to catch up on. The most widely-read blog is a review of global survival rates in waders and the least popular (so far) is one that looks at site fidelity in breeding Black-tailed Godwits.

morgan 2018Black-tailed Godwits

There are several WaderTales blogs about the expanding population of islandica  Black-tailed Godwits and the fast-disappearing limosa birds. This year, it was a pleasure to report on the success of ‘head-starting’ as a means of boosting the British breeding limosa population.

  • Just one Black-tailed Godwit tells one godwit’s life story for the three years after ringing, using observations by birdwatchers in four countries.
  • Site-fidelity in Black-tailed Godwits looks at how the head-starting programme to support the East Anglian population of limosa might be affected by philopatry.
  • Head-starting Success reports on the joint RSPB/WWT project to increase the Black-tailed Godwit breeding population in the Nene, Ouse & Welney fens.

blog whimbrelIceland-based research

The range of wader research in Iceland has expanded over the years and these blogs give a taster of the the breadth of the work.

blog stalkingSingle-species studies

This section is a bit of a miscellany. Each blog is focused on a particular species and is usually based on a scientific paper that highlights a broader issue of conservation importance.

  • Well-travelled Ringed Plovers from Chukotka in north-east Russia spend the winter in Somalia, Egypt, the Red Sea & the Persian Gulf.
  • Green Sandpipers and Geolocators summarises a Ringing & Migration paper about changing behaviour patterns in Green Sandpipers that wore geolocators.
  • Fewer Spotted Redshanks reviews migration patterns and changes in abundance of the species, in a British & Irish context.
  • Starting moult early focuses on the timing of moult in Golden Plover populations. It turns out that it’s tough to find a three-month period in which to moult.
  • Iceland to Africa, non-stop discusses the speed of migration of Icelandic Whimbrel in spring and autumn.

malpasIssues in wader/shorebird conservation and science

Waders across the globe are subject to huge pressures, with several species close to extinction. In some areas we are seeing reduced annual survival – which is a serious issue in species which were thought of as long-lived birds – and many populations are finding it hard to raise sufficient youngsters to sustain numbers.

  • Waders are long-lived birds! Some thoughts on the longevity records for BTO-ringed wader species and the value of monitoring survival.
  • Measuring shorebird survival is a global review that explores the geographic, seasonal and sex-based variation in survival rates across wader families.
  • Curlew Moon has at its heart a review of Mary Colwell’s book of the same name but also summarises some of the issues being faced by Curlew in Ireland and the UK.
  • Black-tailed Godwit and Curlew in France provides background to the debate about a hunting ban or moratorium in France.
  • Tool-kit for wader conservation provides an overview of the tools that are available to conservationists and site-managers working on wet grasslands.
  • Deterring birds of prey summarises a paper about Diversionary Feeding; one way to keep protected predators away from wader chicks.
  • Leg-flags and nest success investigates whether nesting success of small waders (shorebirds) is affected by wearing leg-flags.

Want to read more? To see a full list of the WaderTales blogs that have been published since 2015 CLICK HERE.

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GFA in Iceland

Graham (@grahamfappleton) has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland.  He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.

 

WaderTales blogs in 2017

19 WaderTales blogs were published in 2017, celebrating waders and wader research. Many of the articles are based on newly published papers, with the aim of making wader science available to a broader audience. Click on a link in bold to read an individual blog. 

Wader/Shorebird science and conservationringed-plover

Black-tailed GodwitsDSCN1827

b-dunlinIceland-based research

Blog adultBreeding Lapwings

Upland CurlewsRC single bird muddy edge

There are nearly 30 other WaderTales blogs. Here’s the full list. The intention is to add one or two new blogs each month. You can sign up to receive an e-mail notification when a new one is published.


GFA in IcelandGraham (@grahamfappleton) has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland.  He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.

25 years of wader declines

This article summarises a Bird Study paper arising from a 25-year Scottish study of breeding Lapwing, Oystercatcher, Redshank & Curlew. The story is set against a backdrop of a changing farming landscape.

RC LapThe interesting and sobering feature of this paper about breeding waders by Mike Bell and John Calladine is that its focus is a ‘normal’ area of farmland in Scotland. If you’ve taken the A9 north of Stirling, through Strathallan, then you’ll have driven past the fields. Perhaps you might even have noticed displaying Lapwing, Oystercatcher, Curlew and Redshank? Over a 25-year period, the number of breeding waders in this valley and another one that runs northwest and that can be seen from the B827 has dropped from 600 pairs to just 76 – that’s a loss of 87%, or over 20 pairs per year.

So, what has changed in this part of Scotland that might be linked to these declines? The authors conclude that the reduction in numbers can be linked to changes in field management. Put simply, there are too few bare fields in the spring for Oystercatcher (down 95%) and Lapwing (down 88%). These two species hide their nests in ‘plain site’; they watch out for predators, take off early and hope that the eggs are coloured cryptically enough to avoid detection. Having left their nests, they attempt to deter and/or distract prowling crows etc.  Redshanks (down 87%) and Curlew (down 67%) have also declined, even though they hide their nests in long grass, about which more later.

map graph

Lapwing declines in the Strathallan area are not that much different to those that have been charted across much of Britain & Ireland

In for the long haul

In a survey in the late 1980s, this area of Strathallan held an important assemblage of farmland breeding waders, with particularly high densities of nesting Lapwing. Land use in the valley is predominantly agricultural, with a mixture of arable fields and grazing by sheep and beef cattle. It is a relatively open landscape with few hedgerows, some scattered shelter belts and small conifer plantations.

KS RedshankThis study started in 1990, when breeding densities of nesting Oystercatcher, Lapwing, Redshank and Curlew in the core area were still high, at 11.7, 35.6, 4.7 and 3.3 pairs/km2 respectively. Unlike a PhD project, which might include three years of data, Mike Bell has kept this survey going for 25 years. Mike is the volunteer Regional Representative for the British Trust for Ornithology’s Perthshire region.

Breeding waders within a core area of 65 fields and a small amount of wet fen were surveyed annually from 1990 to 2015. The field sizes were small, by modern standards, with only five fields larger than 20 ha. An additional 1 km2 of lowland mixed farmland was surveyed in most years, 4 km2 of moorland rough grazing was surveyed in four years and another 5.3 km2 of enclosed and unenclosed rough grazing and moorland was surveyed at the beginning and end of the survey period only.

Land management and usage were recorded for each field on the first visit in April or early May. Spring sward height in each field was recorded as one of three categories: no vegetation, short (<10 cm) or long (>10 cm). These sward categories comprised the following field types:

  • bare – ploughed or tilled land with no emergent vegetation
  • short – managed grass for grazing or mowing for hay or silage, rough grass, rush pasture, spring arable, setaside/fallow.
  • long – managed grass, rough grass, rush/pasture, setaside/fallow, heath/moorland, marsh/wetland, unmanaged rank grassland and woodland/scrub.

Where to find waders in Strathallan

In the early 1990s, Strathallan supported around 36 Lapwing pairs/km2 across the core study area, which is comparable with some of the highest densities reported anywhere in the UK. During the 25-year study, as the numbers of Lapwing, Oystercatcher, Redshank and Curlew declined, an increased proportion of the remaining breeding waders became restricted to areas with fields classed as ‘bare’ in spring, while the greatest losses were in fields with ‘short’ and ‘tall’ spring sward heights (see figure).

graphic

Changes in breeding densities of waders in Strathallan, on fields with different sward heights

Breeding densities of Curlew were low throughout the study area and, although overall numbers declined, there was low power to detect statistically significant changes. There were different patterns of change for Lapwing, Oystercatcher and Redshank within fields of different spring sward heights:

  • The least marked changes were in fields with no vegetation in spring.
  • Fields with short swards showed the largest declines.
  • The tallest spring sward heights supported the lowest densities of the three wader species, with Redshank present generally at low densities in all vegetation categories.

UK BBS

UK-wide Breeding Bird Survey trends for Oystercatcher, Redshank and Curlew. BBS is organised by BTO in partnership with JNCC and RSPB.

A changing farmland landscape

Sward heights reflected changing farming methods. Looking at the fields in terms of cropping regimes.

  • The highest densities of Oystercatcher were in spring-sown arable crops.
  • Rush pasture was the most favoured field type for Lapwing and Redshank at the start of the study but the amount of this habitat declined during the study, as farmers created semi-permanent pastures for over-wintering sheep. When this happened, birds became more restricted in their nesting distribution.
  • By 2015, very few fields were still under a crop rotation of grass and spring arable, that would have delivered a mosaic of sward structures. By this time, half of the Lapwing pairs were nesting in just four fields.

Breeding success

The breeding success of Lapwings was estimated in five sample fields that could easily be observed from roads or tracks without disturbing the adults. Lapwing productivity was less than 0.60 young fledged/pair (the bench-mark for a typical stable population) in all but three years and it was less than 0.25 young fledged/pair in 14 of the 22 years. With very low recruitment rates, it is not surprising that the Lapwing is in decline.

There are several WaderTales blogs about Lapwings breeding in lowland wet grassland, including A helping hand for Lapwings. A full list of WaderTales blogs can be found here.

What is changing?

TGG Oyc

The changing fortunes of Oystercatcher are discussed in this WaderTales blog

Within a mixed arable-pasture farmland environment, bare field and short swards in spring appear to be important to breeding waders. Losses of these preferred habitats type don’t appear to fully account for the decline in numbers, however.

Alongside changes to farmland habitats, other potential factors that could have contributed to the decline of the wader population in Strathallan include an increased incidence of poor spring weather, increased disturbance (including from dog-walkers in some fields in some years) and an increase in predators. Mike Bell thinks that one of the reasons for a possible link between productivity declines and wet weather is that birds are nesting in sub-optimal (long) grass and hence more affected by wetter conditions. He writes about this and potential reasons for increased disturbance in an upcoming article in Scottish Birds. A link to the Scottish Birds article will be included when available.

Densities of avian predators increased in Strathallan during the study period, with higher breeding densities of Carrion Crow and Buzzard and an increasing frequency of bigger flocks of non-breeding crows. There was no detectable change in breeding success during the study but it is possible that nest success was already depressed by predation when the study commenced.

A relentless decline

GHH pictureAlthough previously identified as a good area for breeding waders, in a Scottish context, there is nothing unique about this Strathallan study area. It is good to see these issues explored in Bird Study, the BTO journal. I am sure that the editor, Ian Hartley, will have been pleased to publish a paper based on a nice mix of dedicated fieldwork and scientific analysis – that’s what the BTO is all about.  If you want to understand the (not yet fully explained) sad demise of breeding waders in Scotland, check out the figures in the paper. These show a relentless, 25-year decline in nesting densities across a range of habitats and some less-than-subtle changes in the way that fields are now managed.

Here’s a link to the paper:

The decline of a population of farmland breeding waders: a twenty-five-year case study by Michael V. Bell & John Calladine in Bird Study, 64:2, 264-273 DOI: 10.1080/00063657.2017.1319903


 GFA in Iceland

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

@grahamfappleton

 

 

Black-tailed Godwit pairs – the importance of synchrony

How long does a godwit wait around to see if last year’s mate will turn up?

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Newly-arrived Black-tailed Godwits. Time for a wash & brush up and then off to territory?

Colour-ringing enabled Tómas Gunnarsson to follow the lives of pairs of Black-tailed Godwits nesting near his parents’ home in Iceland. In this world, that is ruled by timing and opportunity, the pairings, divorces and re-pairings could form the plot for a TV soap-opera. The studies turned into a fascinating Nature paper that was written up in The Telegraph newspaper. The two main characters were christened Gretar and Sigga  by the journalist but they’re more commonly known as RY-RO and RO-RO.

A tale of two godwits

post-bird

How long should this godwit wait for its mate?

2002: Colour-ringed Black-tailed Godwits RY-RO (red yellow – red orange or Gretar) and RO-RO (Sigga) bred successfully in Laugaras, in the inland part of Iceland’s Southern Lowlands. Come the autumn, they left Iceland. Sigga (the female) probably spent the winter in Portugal, although she was only seen there in later years, and Gretar opted for the somewhat colder conditions of eastern England.

2003: Next spring, Sigga arrived on territory on 6 May, before her mate. She cannot have known whether he was late or dead when she made the decision to move in with a new male, who was later colour-ringed as OR-OO.  When Gretar arrived back a week later, on 13 May, he had to find himself a new female (GG-YO), who had been paired to a different male in 2002.

2004: Come the spring of 2004, Sigga and Gretar arrived at the same time and got back together.

dscn2241

Tómas Gunnarsson with one of the colour-ringed Black-tailed Godwits

This is only one story but it seems to illustrate that there are good reasons to nest with a partner that is well known to you. This could help to illustrate why individual godwits are generally very good at timing their arrival back on territory, to synchronise with their partners, as revealed in this Nature paper, published in 2005.

Gunnarsson, T.G., Gill, J.A., Sigurbjörnsson, Þ. & Sutherland W.J. (2004) Arrival synchrony in migratory birds. Nature, 431, 646-646. DOI: 10.1038/431646a

In the paper the authors described the return of pairs of Icelandic Black-tailed Godwits to Laugaras in the spring of 2003. Godwits generally arrive in Iceland over a one-month period, between mid-April and the middle of May.

pairs-map

Each line joins the wintering locations of a pair of godwits

On average, previously paired males and females in the study arrived within 3.1 days of one another, despite the fact that males and females from the same pair had spent the winter on average about 1000 km apart and that there is no evidence that any pairs had met at passage sites prior to crossing the Atlantic. Arrival synchrony seems to be related to mate retention, as the only divorces occurred in two of the three pairs that arrived more than eight days apart.

Synchrony in timing of arrival on the breeding grounds may be important for retaining a mate from the previous year and avoiding a costly divorce – but how it is achieved is a mystery.

Warmer springs

Tómas Gunnarsson and his father, Gunnar Tómasson, have been studying the timings of spring arrival in south Iceland of a range of species since 1988. In a 2011 paper in Bird Study they estimated that the timing of arrival of the first black-tailed godwit moved earlier by about 5.5 days per decade over that period. Here’s a link to the paper.

graphAs this advance in spring timing of migration was already happening when Tómas was making observations of the paired birds in Laugaras in 2003, we were all interested to see whether the schedules of marked birds would advance in similar ways. Interestingly, we have been able to show that the timing of arrival of individual Black-tailed Godwits is actually not changing at all. There is year-to-year variation in the dates on which individuals arrive, but no trend. Instead it is new recruits into the population that are driving the earlier migration. There’s a blog about this here.

Whilst there are processes in play that mean new recruits are migrating earlier than their predecessors, there must also be reasons why time-fidelity is important for individual birds. Perhaps synchrony increases the probability that individuals will be able to nest with the same mate in subsequent years? This is hinted at by the fact that godwits have been observed to re-pair with previous partners if opportunities present themselves.

Potential benefits of re-pairing with the same mate

For Black-tailed Godwits, not enough is known about the benefits of retaining the same mate. Given that divorce events are rare, it would be hard to measure any consequences for productivity – even if the nests were easy to find and youngsters easy to track – neither of which is the case. For the moment, all that is available is evidence of divorce and the possibility that females will not wait for males that are late.

nest-finding

Nests are well hidden

Black-tailed Godwits are long-lived birds, with breeding territories in which resources are generally predictably distributed, and a pair is likely to be familiar with local predator densities and distributions. Whilst one member of the pair is incubating the eggs, the other spends a lot of time looking out for potential predators, and this mutual protection may well confer benefits for the adults and the eggs. Perhaps knowing the behaviour of one’s partner is important during the incubation period?

The complexities of incubating eggs

If the daily routines associated with parental change-overs at the nest become established over time, might this be an important driver towards fidelity? Fast forward to a paper on shorebird incubation patterns, published in Nature in 2016 by Martin Bulla et al, which might provide some clues:

Unexpected diversity in socially synchronised rhythms of shorebirds Nature 540,109–113 (01 December 2016) doi:10.1038/nature20563

patterns

This actogram from the Bulla Nature paper creates some wonderful patterns

This paper is the result of a collaboration between Martin Bulla and 75 of his wader biologist colleagues, all happy to share data on nest incubation patterns which Martin then analysed. This resulted in an amazing data-set of 729 nests from 91 populations of 32 shorebird species, from which Martin was able to report remarkable within- and between-species differences in nest incubation rhythms.

This study suggests that energetic demands are not an important ecological driver of incubation bout length, but instead that pairs have developed idiosyncratic incubation patterns, possibly as an anti-predation strategy. Effectively, risk of predation, rather than risk of starvation, may have a key role in determining some of the variation in incubation rhythms. This means that species that hide their nests (and themselves) incubate for longer and change places less frequently.

ringo

Incubating Ringed Plovers change places frequently

Ringed Plovers, for instance, walk away from their eggs when a potential predator approaches and change places on the nest frequently. A male or female Redshank, on the other hand, will sit tight and brood for about six hours before exchanging with its partner. While partner A is hunkered down on the nest, partner B leaves the area, so as not to draw any attention to the pre-packaged protein that partner A is sitting on. If B is only going to return when A is ready for a surreptitious change-over then the activities of the two need to be well synchronised.

As the authors point out in the paper, although the context for this comparative study was diversity in biparental incubation, it is possible that diverse behavioural rhythms may also arise in other social settings (for example, in the context of mating interactions or vigilance behaviour during group foraging). These are other circumstances in which it may well be beneficial to know one’s partner.

What does this mean for Gretar and Sigga?

Perhaps fidelity and synchronicity are really important to Black-tailed Godwits? If only their nests were easier to find and nest success was easier to measure! For the moment, all that we know is that pairs of Icelandic Black-tailed Godwits are remarkably synchronous in their arrival times on breeding territory, and something important must have driven the evolution of such a finely tuned migratory strategy.


GFA in Iceland

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

@grahamfappleton