Sixty years of Wash waders

wwrg tt balance

Weighing a Turnstone

The Wash Wader Ringing Group (WWRG) started with a bang on 18 August 1959, when the team made a catch of 1,132 birds in a Wildfowl Trust rocket-net at Terrington, in Norfolk. Over the years, cannon have replaced rockets, catches have become generally smaller and the scientific priorities have been refined, but the Group continues to focus upon discovering more about the waders that use the Wash. This blog attempts to summarises what has been learnt about the waders that rely upon the Wash, the vast muddy estuary that lies between Lincolnshire and Norfolk, on the east coast of England.

Sixty years ago, the first goal was to understand where the vast flocks of waders that visit the Wash came from – a task that would provide great insights into the way that the whole East Atlantic Flyway works. In this time, over 300,000 birds have been caught and ringed on the Wash, as you can see in the table below. Equally importantly, hundreds of bird-ringers from across the UK and scores of visitors from around the world have joined WWRG teams, in order to learn more about the study of shorebirds. Further international collaboration has been fostered through overseas visits by WWRG members and emigration of some key personnel. The impact of the Group is truly global, as you can read in the WWRG report for 2014/2015.

wwrg table

A total of 307,226 birds is impressive, especially when some of the species totals are compared to the national totals of the BTO Ringing Scheme for the whole of Britain & Ireland since 1909. WWRG is responsible for over 40% of the Grey Plover, Knot, Sanderling and Bar-tailed Godwit, with Grey Plover topping the list at nearly 60%. These are terrific achievements for a group of volunteers. I don’t have the figures but I reckon that Nigel Clark has been responsible for the largest number of catches.

Wee quiz: What’s the best match between these Wash waders and the countries that they are quite likely to have come from? Answers at the end of the blog:

  • Species: Bar-tailed Godwit, Black-tailed Godwit, Curlew, Oystercatcher, Sanderling, Turnstone
  • Countries: Canada, Greenland, Iceland, Norway, Finland & Russia
wwrg box

Firing box connected to 4 cannon-nets

In the early days, rocket nets were borrowed from the Wildfowl Trust for an annual summer week of catches, but the development of cannon-nets gave opportunities for all-year ringing. The intensity of the Group’s activities grew in the 1970s, when there was a threat to build a freshwater reservoir on the mudflats. For a couple of years, Clive Minton (founder and leader) persuaded us to visit fortnightly, so that we could get better data on weight-gain and turn-over, using a mixture of cannon-netting and mist-netting. Everything we knew was published by the Group as The Wash Feasibility Study in 1975. These days, the Group gets together about ten times a year for catching and colour-ring-reading sessions.

wwrg oldies

By catching and ringing large numbers of the key species that visit the Wash, the Group was able to generate maps showing what are now well-known patterns of migration (see Which wader, when and why?). Early on in the Group’s history, there was a focus on nine species, with Black-tailed Godwit added as a tenth when numbers increased. Each of these species has its own section below. The maps were prepared for the Wash Wader Ringing Group 2016/2017 Report by Ryan Burrell, using data stored within the BTO archives. Blue dots represent WWRG-ringed birds that have been found abroad. Red triangles represent foreign-ringed birds caught on the Wash. The base maps used are by courtesy of Natural Earth (www.naturalearthdata.com).

Oystercatcher

wwrg map OCThe map alongside clearly demonstrates the strong link between the Wash and Norway. Other interesting things that have been discovered about Oystercatchers:

  • They live a long time. An Oystercatcher that we caught at Friskney on 30 July 1976 broke the longevity record for a BTO-ringed wader when it was shot in France on 4 April 2017 (41 years 1 month and 5 days). It was ringed as an adult so we don’t know the exact age – but it must have been at least 43 years old. There’s a WaderTales blog with a list of longevity records for BTO-ringed waders.
  • When life gets tough, Oystercatchers fail to complete their autumn moult, retaining some of their outer primaries for an extra year. The ability to complete moult and annual survival rates are both affected by cockle and mussel supplies on the Wash. There’s more about this in two papers in Biological Conservation and the Journal of Applied Ecology.

Grey Plover

wwrg GV GVIn the early days of the WWRG, Grey Plovers occurred in much smaller numbers than they do now. Writing in an article about the first 40 years of the Group, Clive Minton told the story of the first catch of 100, made in 1963, that was celebrated with three bottles of champagne provided by the late Hugh Boyd, delivering on an incentive that he had promised.

  • Over half of the Grey Plover that have been ringed in Britain & Ireland since 1909 have been ringed by WWRG since 1959 (58.9%)
  • All of the Grey Plover using the Wash breed in Siberia. Some birds spend the winter on the Wash but there are autumn moulting flocks of birds that will go on to winter in other parts of Britain & Ireland, and spring and autumn passage of birds that travel as far south as West Africa.
  • Grey Plover are late to leave the Wash, with the last departures not occurring until the start of June. Unsurprisingly, they are some of the last waders to return at the end of summer, which puts pressure on birds to finish moult before the short, cold days of winter. Some adults fail to complete primary moult, especially if food supplies are low. There is more about Grey Plover moult in this WaderTales blog.

wwrg map GV KN

Knot

wash knot

First-winter Knot (subterminal bands on wing coverts and, as yet, unmoulted juvenile fethers on upper-parts)

Knot (or Red Knot) are truly international waders, as is shown in this map of movements of islandica  (and a few canutus) birds  to and from the Wash. Several WWRG members have been heavily involved in efforts to understand the decline in numbers of the rufa subspecies in Delaware Bay (on the North American eastern seaboard) and Clive Minton has been at the heart of efforts to explain the sudden drop in survival of piersmai and rogersi adults that winter in Australia and migrate to Arctic Russia via the Yellow Sea (see Wader declines in the shrinking Yellow Sea).

  • We are still learning about Knot migration. The cluster of reports of WWRG-ringed birds in Northern Norway looks odd on this map projection but it turns out that this is a well-used stopping-off point for islandica Knot heading for northern Greenland and NE Canada. This route was first confirmed in 1985, when a joint Durham University and Tromsø University expedition caught 18 Wash-ringed birds in a total catch of 1703 birds.
  • wwrg net set

    Setting cannon-nets

    Many birdwatchers visit the Wash in autumn and winter to see the swirling Knot flocks at Snettisham and Holme. If high tide is at first light, Knot and other waders sometimes roost on Heacham Beach, giving the occasional opportunity to make a significant catch. The most recent of these, on 11 February in 2012, included 2757 Knot, 77 of which were already wearing rings.

  • The most recent analysis of wader populations in Great Britain showed that there was a drop of nearly 20% in wintering Knot numbers (from 320k to 260k) in less than a decade (see Do population estimates matter?). Regular catches on the Wash will help produce estimates of annual survival rates and age ratios of the islandica subspecies.

Sanderling

wwrg sanderlingThe biggest catches of Sanderling are generally in the summer, when the Wash is a meeting point for birds from Greenland and Siberia. July can sometimes see catches of 200 or more birds. Traditionally, a Sanderling catch was the curtain-raiser at the start of Wash Week, an opportunity for the whole team to make one catch before splitting into ‘Terrington’ and ‘Lincolnshire’ teams for the rest of the main summer trip.

  • Wintering Sanderling on the Wash are thought to be exclusively of the race that heads northwest in the spring, to Greenland via Iceland.
  • Late summer and spring see the addition of birds passing through on their way from/to Siberian and Greenlandic breeding areas.
  • I well remember the first time we caught a Sanderling (on 26 July 1975) wearing an Italian ring (caught in Italy 9 May 1975). Thanks to Jeroen Reneerkens (whose work will be covered in an upcoming blog) I now understand that this is probably a bird that migrates from Namibia to Greenland in spring, via the Mediterranean. It will have been on its way back to Namibia when caught in July.

wwrg map SS DN

Dunlin

wash dunlin

Sam Franks, looking for the buffy tips on inner coverts, which distinguish first-year birds from adults

Nearly half of the waders caught by WWRG have been Dunlin – a total of 140,168 up until the end of 2018. There were really big flocks of Dunlin in the 1970s but numbers have dropped over the years, with peak counts now half what they were, according to WeBS data.

  • We caught over 3,500 Dunlin in one week in 1976 but the annual total has exceeded 1,000 in only four of the last ten years. Partly, this reflects a change in behaviour in the summertime, with fewer waders roosting on fields and hence less catchable.
  • Three races of Dunlin visit the UK. Our winter birds are alpina, from Siberia, NW Russia and northern Scandinavia. A lot of July birds are schinzii, breeding in the UK and as far north as Greenland, and we occasionally try to convince ourselves that we have caught an arctica from northern Greenland.
  • Data collected for the WeBS survey suggest that national winter totals have dropped by over 40% in 25 years. This could perhaps partly be explained by a redistribution of alpina, with new generations of young birds settling in wintering areas on the other side of the North Sea. Warmer winters may well make this a more practical proposition than in the 1970s. There’s more about this in this paper.

Black-tailed Godwit

wash blackwit

Newly ringed Black-tailed Godwit, caught in a mist-net at night.

Black-tailed Godwits became a priority species in 1995, when Jennifer Gill (University of East Anglia) started a project to study the movements of individuals, using colour-rings. Nearly 25 years later, the WWRG-ringed Black-tailed Godwits have contributed data to numerous papers, largely focusing upon migration.

  • The Wash is a hugely important area for moulting islandica Black-tailed Godwits. Some birds stay in East Anglia for the winter but others move south and west within the UK, west to Ireland and south to France, Portugal and Spain.
  • There are several blogs about Black-tailed Godwits in this WaderTales contents list.

Bar-tailed Godwit

One of the key things that was learned from the sudden decline in annual survival rates in a range of species that use the Yellow Sea (as mentioned above) is a need for regular monitoring of marked birds. The WWRG’s Scientific Committee set up colour-flagging projects for Bar-tailed Godwit, Curlew and Grey Plover, in order to increase the reliability of estimates of annual survival for three species that the Group does not catch in sufficient numbers to generate good retrap histories. Birdwatchers can help by reporting colour-marked birds here.

wwrg barwit map etc

  • In Bar-tailed Godwits: Migration & Survival there is a comparison of the data generated by a catch of 505 Bar-tailed Godwits in 1976 with the information that has been generated recently, using colour-flags.
  • Bar-tailed Godwits are long-lived birds. A WWRG bird holds the current record for a BTO-ringed Bar-tailed Godwit: 33 years and 11 months between ringing in 1978 and recapture in 2008. BTO longevity records are discussed in this WaderTales blog.
  • Colour-ring reading is now a significant element of Group activities, as described by Rob Pell in the WWRG Report for 2016/2017.

Curlew

Back in the 1970s, Curlew were still hunted on the Wash (paté made from autumn-shot birds was reported to be very tasty). Shooting stopped in Great Britain in 1981, when the maximum winter count on the Wash had dropped to about 3,000 birds, and by 2003/04 the maximum winter count was 15,336. Since then, numbers have declined, in line with national and international trends.

wwrg curlew map etc

  • A large number of Curlew on the Wash in winter are from Finland and surrounding countries. Surprisingly few are of UK origin.
  • Birds wearing WWRG leg-flags have been observed breeding in the Brecks (Norfolk/Suffolk).
  • The Curlew is internationally designated as ‘Near Threatened’. Is this really true when we can still see a field with 1000 roosting Curlew in Norfolk? Answers here.

Redshank

wash redshThe latest population estimates suggest that Great Britain has lost 26,000 wintering Redshank in less than a decade, representing a drop of 20%. Perhaps WWRG data can be used to help to explain these declines? Here are some of the things we know:

  • The Redshank on The Wash in the winter are mainly a mixture of birds from around the Wash, across the UK and from Iceland.
  • In cold winters, Redshank wintering on the Wash die in large numbers. After a period of severe weather in 1991, nearly 3,000 wader corpses were collected from along the tide-line, about 50% of which were Redshank. The winter WeBS counts for Redshank dropped by 50% after this mortality event but have recovered somewhat since then.
  • An analysis of nearly 1,000 dead Redshank showed that about two-thirds were of Icelandic origin. There was a tendency for smaller birds to be more susceptible to cold weather mortality than larger birds of the same species (More information in this paper by Jacquie Clark)

wwrg map RK TT

Turnstone

wash ttWinter Turnstone are birds that will head for Greenland and NE Canada in the spring but recoveries of birds in Finland and other Scandinavian countries indicate a passage of continental birds. African recoveries of WWRG-ringed birds probably include birds from Canada/Greenland and Finland/Scandinavia.

  • Turnstone wearing US Fish & Wildlife Service rings are occasionally caught on the Wash. Some of these rings were put on by Guy Morrison and his colleagues in Alert, Ellesmere Island, Canada. Guy was an early member of WWRG. It’s a small world!
  • The first Wash Turnstone were colour-ringed in 1999, as part of a study to understand why birds were feeding on the docks at Sutton Bridge. There is a WaderTales blog about the resulting paper by Jen Smart and Jennifer Gill. Colour-ringing continues, to measure annual survival rates.
  • Turnstone have a reputation for eating almost anything (including dog excrement and a human corpse) so do not be surprised if you see a colour-ringed bird scavenging for chips on the Hunstanton sea-front.

A few more highlights

Ringed Plover: this is not one of the ten key study species but 1,432 have been ringed between 1959 and 2018. Some birds are local breeders that hardly move anywhere but other birds link the Wash with Greenland, northern Norway, Morocco and Senegal.

wwrg GKGreenshank: The Group supports a colour-ringing project that was initiated by Pete Potts, in Hampshire. More information here.

Spotted Redshank: During the period 1959 to 2018, WWRG ringed a total of 85 Spotted Redshank, representing over 20% of the total ringed in Britain and Ireland since 1909. Amazingly, sixty of these birds were ringed on the same day – 27 July 1975. There is a blog about this catch and the recent decline in the number of Spotted Redshank visiting the UK. Fewer Spotted Redshanks.

Ruff: Until its closure, WWRG members spent many a smelly night at Wisbech Sewage Farm. This was a great place to catch Ruff, Curlew Sandpipers, Green Sandpipers etc. in mist-nets. Group members wrote a paper about Ruff moult and migration.

Rares: Occasionally there are surprises! WWRG has caught one each of Stone Curlew, Pectoral Sandpiper, Broad-billed Sandpiper and Terek Sandpiper. The last bird features in this WWRG blog.

What do we know now?

Migration studies have revealed the importance of the Wash to half a million or more waders each year – birds that spend the whole winter, others that refuel in the spring and vast numbers that rely on the food supplies in the mud to provide the energy for the post-breeding moult. There’s a selection of papers that have included WWRG data here, on the Group’s web-site.

wwrg cr TTThe Group still aims to maintain its general ringing programme, so that a representative sample of the key species carry rings. Colour-ringing projects aim to provide survival estimates for Curlew, Bar-tailed Godwit, Grey Plover and Turnstone, with Greenshank and Black-tailed Godwit colour-rings contributing to migration studies. Birdwatchers who visit the Wash can help by reporting colour-marked birds here, on the WWRG web-site.

WWRG data have been used to help inform decisions about the future of the Wash but the threats keep coming. Studies of migration and seasonal turn-over in numbers contributed hugely to decisions to provide national and international protection to the area and to fend off the 1970s plan to build a freshwater reservoir on the rich mudflats. The information that has been generated by many generations of volunteers over a period of sixty years has been used to manage the level of shellfish exploitation, to inform decisions about wind turbine locations and to manage activities that can cause disturbance.

The Wash Wader Ringing Group is very keen for its data to be used – and not just for impact assessment studies. Click here to learn more.

Diamond Jubilee

PLI

Phil Ireland releasing a Curlew

Over one thousand people are estimated to have contributed to sixty years of the Wash Wader Ringing Group’s activities. We have lived in barns, rolled cars, dug tens of thousands of holes, carried nets for miles, made important catches, had depressing failures, got frostbite, been threatened by surge tides and made friends for life.

In the whole of this period, there have been only two leaders of the Group – Clive Minton (1959-1981) and Phil Ireland (1981-present). Bird ringers, wader biologists and millions of waders owe them both a huge debt of gratitude.

You can read more about the history of WWRG on the Group’s website:

wwrg sunset

Photo at the top of this blog is by Cathy Ryden. Many thanks to her and to other photographers.

Wee quiz:

  • Bar-tailed Godwit – Russia
  • Black-tailed Godwit – Iceland
  • Curlew – Finland
  • Oystercatcher – Norway
  • Sanderling – Greenland
  • Turnstone – Canada

 


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.

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Ireland’s wintering waders

blog KN OC

There’s still space for a few Knot

The island of Ireland is a great refuge for wintering waders, washed as it is by the warm waters of the Gulf Stream. It’s just a quick hop across the Atlantic from Iceland for Black-tailed Godwits, Golden Plovers, Redshanks and Oystercatchers. For birds travelling from Siberia, such as Bar-tailed Godwits and Grey Plovers, it’s a longer journey but one that’s well worth making.

If Ireland is such a great destination for shorebirds, why do the latest population estimates reveal a decline of nearly 20% in wader numbers in just five years?

This blog summarises the wader information, published in Estimates of waterbird numbers wintering in Ireland, 2011/12 – 2015/16 in Irish Birds. The totals in the report are split into counts for the Republic of Ireland and Northern Ireland but, given that waders don’t recognise borders, most of the comments in this blog relate to the whole of Ireland. The results for 2011-16 have been compared to the equivalent figures for 2006-11 and set in the context of the totals of wintering waders throughout the East Atlantic flyway, as combined by Wetlands International. The Irish data were collected by the amazing volunteers who make monthly, winter counts for I-WeBS (BirdWatch Ireland & National Parks & Wildlife Service) and WeBS (BTO/RSPB/JNCC in Northern Ireland).

blog paper

Headline figures

Fifteen species are considered in this report. The most numerous are Lapwing and Golden Plover, which account for an estimate over 170,000 individuals between them, whilst the smallest contributions are made by Purple Sandpiper (662) and Greenshank (1317). In total, the average estimated number of waders in the winters during the period 2011-16 is 429,170 birds but it should be noted that this total excludes two widespread and common species – Woodcock and Snipe – as well as the enigmatic Jack Snipe. To update previous estimates for these three species, which were last made using distribution and abundance data collected during Bird Atlas 2007-11 fieldwork, it would be necessary to run a special inland survey. There is also some question about Lapwing and Golden Plover numbers, simply because so many of these birds are found in areas that are not covered by monthly waterbird counts.

Biggest changes

blog SA

The Irish Sanderling population has increased by 13.2% in five years

The combined average winter maximum count of the 15 wader species examined in the report declined by 102,310 birds (19%) in the five-year period between 2006-11 and 2011-16. This is extremely worrying. If Lapwing and Golden Plover are excluded from consideration, as there is uncertainty about the completeness of counts, there are five species that are of particular concern; Knot numbers dropped by more than 40% and Oystercatcher, Dunlin, Redshank and Turnstone numbers by more than 20%. The Purple Sandpiper population estimate dropped by over 30% but relatively small numbers of this species are encountered around the rocky coast of Ireland. The only species to show increases were Sanderling, Bar-tailed Godwit, Black-tailed Godwit and Greenshank.

In a previous WaderTales blog, there is detailed information about population estimates for Great Britain: Do population estimates matter? In Great Britain there were similar rates of decline for Redshank and Turnstone (measured over an eight-year, rather than five-year period) but much smaller falls for Knot, Oystercatcher and Dunlin. The possible causes of the changes in Ireland are discussed in the paper in Irish Birds. They include flyway-scale declines (e.g. Knot and Curlew) and the possibility that more birds from the east are now wintering on the coasts of mainland Europe (e.g. Dunlin and Grey Plover).

blog mixed

European context

Blog tableThe table alongside gives an indication of the relative importance of Ireland, Great Britain and, together, the British Isles to the birds that use the East Atlantic flyway during the winter period. The three columns show the percentage of each species found in each of the three regions. Summarised international counts, as used in the paper, were kindly provided by Wetlands International. In the case of four species, Ireland is host to a significant proportion of the Icelandic breeding population (Oystercatcher, Golden Plover, Black-tailed Godwit and Redshank).

Notes: As mentioned earlier, there are questions about the precision of estimates for Lapwing and Golden Plover, although the population trends are reliable. The Ringed Plover percentage seems high (98% for British Isles) but this may well reflect the fact that the Non-estuarine Waterbird Survey has uncovered significant numbers of the species on the open shores of Great Britain. These extra birds are included in the new totals for GB but not in the flyway total. The percentages for Black-tailed Godwit seem low, as discussed further down.

Ireland is particularly important for Golden Plover, Ringed Plover, Bar-tailed Godwit and Black-tailed Godwit, as well as for the Icelandic subspecies of Redshank. Greenshank is excluded because the percentages are below 1% of the flyway population for Ireland and for Great Britain.

blog BA horiz

11% of Bar-tailed Godwit on the East Atlantic Flyway spend the winter in Ireland

Although there are important populations of breeding waders in Ireland, the shores and wet fields of the island really come into their own during July and August, when the first ‘winter’ waders arrive, and they only become quiet again in April and May, when the last birds head north and east to nest. A successful breeder is likely only to be away for four or five months, meaning that these waders will spend by far the largest part of the year in Ireland. The island is even more important for immature birds. Young Oystercatchers that arrive from Iceland, Scotland or perhaps Norway when just a few months old are likely to spend the next 30 months in Ireland before making their first trip north. There is a WaderTales migration blog about the Oystercatchers that fly from Iceland: Migratory decisions for Icelandic Oystercatchers.

blog OC

Curlew in the Republic

Curlew numbers in the Republic of Ireland illustrate the relative importance of the country for breeding and non-breeding populations. The winter population estimate for Curlew in the Republic is 28,300 but the most recent survey conducted by BirdWatch Ireland and NPWS, as summarised in the WaderTales blog Ireland’s Curlew Crisis, reveals that the number of breeding birds has crashed to just 138 pairs. Accounting for young Irish birds that have not started to breed, and even if we assume that all Irish birds stay in the country for the winter, then the total number of home-grown Curlew seen in non-breeding flocks is at most about 400. This means that every winter flock of 70 Curlew will contain an average of just one Irish bird. Far more deliver their curl-ew calls with a Scottish, Finnish or Swedish ‘accent’. The map below shows the migration pattern for Curlew ringed in or found in Britain & Ireland.

blog migration map

Black-tailed Godwit

In the table above, it looks as if 18% of Iceland’s Black-tailed Godwits spend the winter in Ireland. This is probably an underestimate of the importance of the Republic of Ireland and Northern Ireland to the species. The flyway total for Black-tailed Godwit is given as between 98,000 and 134,000 in the Irish Birds paper and the percentage figure is based on 110,000. These three figures are almost certainly too high, as they build upon country-based estimates that have subsequently been revised. The true figure is likely to be around 60,000 to 65,000 (J. Gill pers. comm.), which would suggest that the maximum winter count in Ireland of 19,800 represents at least 30% of the islandica Black-tailed Godwits. Add in extra birds that moult in Ireland in the autumn, before moving further south to countries such as Portugal, and other birds that spend spring months on the island, and Ireland becomes even more important for Black-tailed Godwits!

blog BTMost birdwatchers might associate flocks of waders with estuaries but Black-tailed Godwit is an excellent example of a species that also relies on inland fields, either close to estuaries or along river valleys. Whilst undertaking PhD research on Black-tailed Godwits in south-east Ireland, Daniel Hayhow showed that there is insufficient time to find enough estuarine food during the mid-winter tidal cycles, with birds topping up their resources on grassland. You can read more about the energetic consequences of choosing to winter in eastern England, Portugal and Ireland in this blog: Overtaking on migration. Site designation and planning decisions need to take account of the grassland feeding requirements of Black-tailed Godwits and other waders that do not spend all of their time on estuaries, particularly Curlew.

Conservation implications

Some of the issues facing waders may be related to threats that species face in the breeding grounds. However, it may be easier to introduce measures that provide better protection and feeding opportunities in the wintering area, as ways of maintaining populations through the non-breeding season, than it is to deal with problems in the High Arctic. (Although we can all help by reducing carbon emissions, in order to minimise global warming, of course).

blog OC SA

Reading the report, I was reminded of the need to consider a range of conservation issues:

  • Care needs to be taken when considering shoreline developments. These can directly remove habitat or squeeze the width of the intertidal zone.
  • Increased harvesting of shellfish can affect species such as Oystercatcher and Knot and brings risks of introducing alien species and diseases.
  • In the drive to cut carbon emissions, tidal, wave and wind power developments need to be sited in appropriate places.
  • Off-shore harvesting of growing kelp beds has been suggested, as a way of producing fertiliser and biofuels. This process could reduce protection for beaches and change the availability of resources for species such as Turnstone and Sanderling.
  • Grassland areas need to be considered (and not just estuaries) when planning protection for species such as Curlew and Black-tailed Godwit.

blog RKPaper

Estimates of waterbird numbers wintering in Ireland, 2011/12 – 2015/16. Brian Burke, Lesley J. Lewis, Niamh Fitzgerald, Teresa Frost, Graham Austin, and T. David Tierney. Irish Birds No. 41, 1-12.

There is a complementary paper in British Birds, covering Great Britain. The wader information is summarised in this blog: Do population estimates matter?


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

WaderTales: a taste of Scotland

11 Dec RK LWhy is Scotland losing its breeding waders? The latest WaderTales blog with a Scottish flavour is a story from Strathallan, based on observations by Mike Bell.

“If you’ve taken the A9 north of Stirling, through Strathallan, perhaps you might 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.”

Click here for a link to the blog

 

And here are five more uniquely Scottish WaderTales blogs

headerWaiting for the wind – spring flocks of Black-tailed Godwit on Scotland Observations from Tiree by John Bowler and others gave a unique insight into what happens if northerly winds set in at migration time.

scottish-wadertalesEstablishing breeding requirements of Whimbrel  focuses on the different habitat needs of adults and chicks in Shetland.

Oystercatchers: from shingle beach to roof-tops details significant declines in Scotland, at least partly explained by predation. An increasing number have now taken to nesting on roofs.

UK Dotterel numbers have fallen by 57% presents the results of an RSPB survey that was published in Bird Study.

Prickly problems for waders explains how SNH are trying to deal with introduced Hedgehogs in the Outer Hebrides, where they are a major problem for breeding waders.

And here are another nine which may well appeal to Scottish birdwatchers:

  • NEWS and Oystercatchers focuses on the waders that  winter on coasts, instead of estuaries. It was written to promote the 205/16 coastal survey run by BTO.
  • A place to roost discusses the importance of safe, high-tide roosts, especially in terms of energetics. What are waders looking for?
  • The not-so-Grey Plover focuses on the moult of the Grey Plover but the principles are relevant to determining the ages of birds of other species.

There are over 40 WaderTales blogs. 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.

Why do Turnstones eat chips?

Turnstones feeding on discarded chips in Hunstanton – a sign of desperation or just opportunism?

019_7 edited (2)

Turnstones feeding with Starlings and Collared Doves at Port Sutton Bridge (Allison Kew)

I can think of three good reasons to worry about Turnstones wintering in the UK and a couple of arguments to suggest that that the species will cope – whatever problems they might encounter.  On the negative side, numbers have dropped by 50% in just thirty years, they breed on the most northerly (and hence climate-sensitive) bit of available land in the northern hemisphere and we frequently see them scavenging on unnatural foods, such as discarded take-aways.  On the plus side, Turnstones are long-lived birds that will eat almost anything.

Tough waders

turnstone

From Time to Fly, by Jim Flegg (BTO)

The Turnstones we see around the shores of the British Isles in the winter are almost all from Greenland and the Canadian Arctic (green arrows on map). There’s a hint, in the BTO’s Migration Atlas, that east coast birds are more likely to have bred in eastern Greenland, whilst birds from western Britain tend to head further west, to arctic islands such as Ellesmere. A few Scandinavian breeders may winter here but these birds mostly turn up on spring and autumn passage (orange arrows on map).

In a 1985 paper in Bird Study, Neil Metcalfe and Bob Furness showed that 95% of Turnstone colour-ringed on the Clyde arrived back there after the breeding season, having undertaken two Atlantic crossings and bred in the High Arctic. Perhaps unsurprisingly, given this high survival rate, the BTO longevity record is over 20 years. This is higher than that for any other Turnstone ringed (or banded) as part of a European or American ringing scheme, but this record may well increase still further, now that birds wear harder, longer-lasting rings.

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Checking to see what the tide has washed up (Graham Catley)

One way Turnstones can survive is to eat other birds, as we found in the winter of 1990/91, when nearly 5000 waders were found dead in south-east Britain, after a period of particularly cold weather. Although 2442 Redshank, 1357 Dunlin, 501 Grey Plover, 149 Knot, 139 Oystercatcher and 90 Curlew corpses were found on the tide-line, there were very few reports of dead Turnstones. Some of those that were still to be found on beaches were feeding on the bodies of other waders. (Further details in Clark, J.A., MPhil Effects of severe weather on wintering waders, University of East Anglia, 2002)

Turnstones are physically tough too. On one night in James Bay, Canada, I accidentally ran over one on a beach when driving a three-wheel ATV motor-bike. It was under the tyre (and me) before I had time to spot it. I stopped and picked the gravel out of its feathers and it flew off, apparently none the worse for the encounter.

Dinner is served

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There’s not much of a jump from scavenging for fish bits on a jetty to waiting for chips outside a fish & chip shop (Graham Catley)

As a species, Turnstones are remarkably adaptable when it comes to their choice of food outside of the breeding season. They can be found on the most exposed of shores (feeding in breaking waves along with Purple Sandpipers), on the flat sands of estuaries (perhaps in shellfish beds with Oystercatchers), or on the receding tideline with Sanderling. Colour-ringing tells us that individuals adapt to particular feeding areas, whether these be Scottish rock-pools or under bar-tables on beaches in the Caribbean. If opportunities arise they take them – when high tides wash maggots out of seaweed beds, when cockle diggers have been disturbing cockle beds, if storms throw up shellfish onto the tideline or if a carcase washes up on a beach. There’s even an oft-quoted example of Turnstones feeding on a human corpse (Mercer, A. J. 1966. ‘Turnstones feeding on human corpse’. Brit. Birds, 59: 307). 

Numbers

The latest winter population estimate for the UK is 51,000 Turnstones with about 20,000 of these on estuaries and the rest on the open coast-line. The species is only amber-listed on the latest UK Birds of Conservation Concern list, based on a decline of 20-30% in the 25-year period under consideration.

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59% of UK Turnstone were found on open shores during the NEWS-II survey

According to the latest Wetland Bird Survey data, the UK population in 2013/14 was about the same as during the period 1974 to 1983 but, in the intervening years, numbers have risen steeply and then fallen again. Were the chosen window for conservation-listing to be 1987/88 through to 2013/14, the decline would be about 50% and the species might have been red-listed. Internationally, the Ruddy Turnstone is of ‘least concern’, when assessed against BirdLife International criteria, reflecting a wide distribution, large population and relatively shallow decline in numbers.

Given that the current trend in Turnstone numbers is very much downwards, perhaps the species should be receiving a bit more attention?

That’s a strange place to find Turnstones?

When bird species are in trouble they tend to turn up in odd places – Barn Owls hunting along roads in snowy weather, for instance – but sometimes the ‘go to’ food becomes a favourite – as we saw when Siskins started homing in on bird feeders. Turnstones are commonly found foraging in non-tidal situations and a neat paper by Jennifer Smart and Jennifer Gill aimed to work out whether they are forced to do this or they’re there because these are good options.

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Catching Turnstones at dawn on the brick-weave of the dock required some lateral thinking. Note the sand bags used to make emplacements for the cannon (Allison Kew)

A flock of Turnstone on the Wash (eastern England) was first noticed feeding on the dock-side at Sutton Bridge in 1998. Over the next few winters, these birds provided an opportunity to try to work out whether this behaviour was a consequence of poor food supplies on traditional feeding areas or just opportunism. In their introduction to the paper in Biological Conservation, arising from this work, Jennifer Smart and Jennifer Gill said “Many species of shorebird typically forage almost exclusively on intertidal habitats. When such strongly maritime species choose to forage on non-intertidal habitats, it may either be a response to deteriorating intertidal conditions or to the discovery of more profitable resources in non-intertidal areas. Methods which allow distinction between these two will clearly be important for identifying problems in intertidal habitats”.

Smart, J. & Gill, J.A. (2003) Non-intertidal habitat use by shorebirds: a reflection of inadequate intertidal resources? Biological Conservation, 111, 359369.

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Turnstones feeding on grain and fish-meal: Allison Kew

Port Sutton Bridge is a four-berth facility on the canalised River Nene, four kilometres inland of the Wash. Although it handles a variety of cargo, the two that interest Turnstones are grain and fish-meal, quantities of which are spilt on the dock and presumably in the water. By colour-ringing individuals, using cannon netting techniques that had to be specifically adapted by the Wash Wader Ringing Group for the purpose, and counting birds at different stages of the tide, in a variety of weather conditions and over the course of the non-breeding season, Jen Smart aimed to understand how individuals were using the site.

Turnstone had first been observed using Port Sutton Bridge in January 1998, when a flock of 196 birds was present, grain exports having commenced at the port ten years earlier. In the period of the study (1997-2002) the maximum count was 576, a significant proportion of the estimated turnstone population of 600 on the Wash, according to Wetland Bird Survey data, although the Turnstones’ habit of roosting on offshore buoys over high tide (when counts take place) may make this WeBS total a slight underestimate.

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Colour-rings were used to measure turn-over. Ten birds were also radio-tagged. All 9 adults split their time between mud-flats and the port area but the one juvenile was only ever recorded in or around the port (Jen Smart).

Turnstones did not head straight for the port when they returned from Greenland and Canada. Very few fed there in the period July to December and, when they did start to use the site, large numbers generally only occurred at high tide, when other food sources were unavailable, and on colder days, when the availability of invertebrates on mudflats is often reduced and energetic demands are likely to be higher. The numbers and timing indicated that the switch to the dockside arose because the non-intertidal habitats were being used to supplement the diet on the preferred intertidal mudflats.

Jen Smart spent a lot of time watching Turnstones feed at the port, collecting their droppings and sampling the food available. In the paper she clearly shows that there was more than enough food for the whole Wash population on most days, so most birds were actively choosing not to make full use of the resources available most of the time. This could have been because of disturbance on the site (although the birds tolerated people) but was more likely to be realated to actual or perceived predation risk, and the lower quality of the foods available.

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Three Canadian-ringed bird were observed at Sutton Bridge. This one spent several winters in Cleethorpes, Lincolnshire (Chris Atkin)

Given that grain has a low fat content and there are high risks of predation and disturbance associated with the site, why did Turnstones choose to forage there? One possibility is that declining shellfish stocks on the Wash forced the birds to exploit alternative food sources. Within faecal samples collected on the dock, the commonest intertidal prey remains were shells of young cockles, although hard-bodied prey such as these will be more prevalent in faecal remains than soft-bodied prey. This strongly suggests that grain and fishmeal were acting as a ‘top up’. Interestingly, when there was a heavy fall of cockle spat in 2000 there was a reduction in numbers of Turnstone at the port in the next winter.

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Three colour-ringed Turnstones at Heacham, 20km from Sutton Bridge (Jen Smart)

By looking at the pattern of counts, Jen Smart & Jenny Gill could infer that the port is a source of supplementary food and not a preferred resource. This allowed them to suggest that Turnstones may have been reacting to declines in intertidal prey that also affected other shorebird species on the Wash over the same period. The availability of wheat grain at Port Sutton Bridge, in addition to field and river edge habitats, appeared to have been playing a highly significant role in maintaining the internationally important status of Turnstone on the Wash. In this study, scientists were able to assess the likely cause of the habitat switch before any decline in the Turnstone population had taken place.

Implications

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Showing off a full set of 5 colour-rings (Richard Chandler)

The invertebrate populations of intertidal mudflats in NW Europe are currently threatened by sea level rise, development pressures, disease, exploitation of shell fisheries and climate changes which can alter the suitability of the habitat for particular species. The impact of these processes is often unclear because long-term, broad-scale data on intertidal invertebrate populations are rare. Changes in the distribution or species such as Turnstone, Redshank and Oystercatchers, all of which are known to switch to terrestrial habitats, may therefore often be the first indication of pressures on bird populations that have been caused by a decline in invertebrate abundance. These changes in local bird numbers can be picked up because there are regular counts of waders on estuaries, particularly by birdwatchers contributing to the Wetland Bird Survey and the associated Low Tide Counts.

Desperation or Opportunism?

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Grahame Madge photographed these Turnstones in Brixham (Devon), feeding on scraps of fish & chips

So, should we be worried if we see Turnstones outside a fish & chip shop? I guess that, once an individual Turnstone has discovered that there’s an easy source of extra food on a Norfolk sea-front or under the tables of a beach bar in the Caribbean, then it’s probably going to continue to exploit these opportunities. On the other hand, if the flock is getting bigger then perhaps we should ask “why?”

Smart, J. & Gill, J.A. (2003) Non-intertidal habitat use by shorebirds: a reflection of inadequate intertidal resources? Biological Conservation, 111, 359369.


 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.

@grahamfapppleton

 

NEWS and Oystercatchers

It’s amazing what you can find when walking along a beach with a pair of binoculars

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Curlews waiting for the tide to drop: Graham Catley

Thousands of British and Irish birdwatchers visit estuaries but there’s a lot of coastal habitat that gets little attention.  That’s where you’ll find 87% of the UK’s Purple Sandpipers, over half of the Turnstones and nearly half of the Ringed Plover – or those were the figures nine years ago.  It’s time to update these estimates, which is where NEWS-III came in. That’s the catchy name for the third Non-estuarine Waterbird Survey, which operated in the UK and Ireland over the period 1 Dec 2015 to 29 Feb 2016.

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We’ll be looking out for colour-ringed Oystercatchers: Tómas Gunnarsson

We covered 6 beach sections as our contribution to NEWS-II over the Christmas period 2006/07: three horrible stretches right next to the main A78 along the Clyde coast and three lovely beaches on the island of Cumbrae. We found 57 waders on the first set, while dodging the traffic, and 184 on a very relaxed day trip from Largs by ferry. There were comparable numbers of Curlew, Turnstone and Redshank but more Oystercatchers on the wider, island beaches.  That’s where we also found our only Ringed Plover, as well as 11 Purple Sandpipers and 3 Lapwing.

cumbrae comparisonThis year, we found far fewer waders than nine years ago. The table alongside provides a comparison for the three sections that we covered on Cumbrae for NEWS II and NEWS III. We failed to find any Purple Sandpipers in any of the 17 sections of the Clyde coast that we covered but were surprised to see a total of 5 Greenshanks. There seemed to be far fewer seabirds too. This is just a tiny snap-shot that may not be representative of the picture across the whole of the coastline of Britain & Ireland. Let’s hope that, despite the stormy weather, there was sufficient coverage for robust anlayses to be carried out by BTO staff.

RP WeBSWe know that wader number on estuaries are changing.  For instance, in the last few years, numbers of Ringed Plover in the UK have been falling (see figure).  The declining line indicates a significant drop but it won’t be quite such a concern if this year’s NEWS-III surveyors find that there are now more Ringed Plovers on open coasts.  That may seem like an optimistic suggestion, unless you look at changes between NEWS (1997/98) and NEWS-II (2006/07).  During this period, at the same time that WeBS counts of estuaries were falling, there was actually a 25% increase in Ringed Plover numbers on open coast.  Perhaps this redistribution from estuaries to open coasts has continued?

NEWS tableTwenty-one species of wader were recorded during NEWS-II, with Oystercatcher being the most numerous with an estimated total of 64,064 for the whole non-estuarine coastline of the UK. The full report is available on the BTO website .  With support from hundreds of volunteer birdwatchers it was possible to make population estimates for the 12 most numerous species, including the non-estuarine specialists, Ringed Plover, Sanderling, Purple Sandpiper and Turnstone.  These four species accounted for estimates of 15,230, 6,295, 11,306 and 30,122 individuals respectively.  The table alongside shows the intertidal-zone totals and the percentage of the total UK population that each estimate comprises, based on Population estimates of birds in Great Britain & the United Kingdom by Musgrove et al which was published in British Birds.

Five of the species that were in the top 12 for NEWS-II have been categorised as near-threatened by IUCN/BirdLife.  Oystercatcher is the most numerous of the five, with over 64,000 in intertidal areas of the open coast, representing nearly 20% of the national wintering population.  There are relatively small numbers of Bar-tailed Godwit, Lapwing and Knot but 26,744 Curlew is equivalent to 17.8% of the UK total.   There’s a WaderTales blog about the near-threatened designation of Curlew.

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59% of the UK’s Turnstone ar found on the open shore: Derek Belsey/BTO

Unfortunately for the scientists who organised NEWS-III there is a huge disparity between the distribution of birdwatchers and the number of coastal stretches that would ideally be surveyed, so let’s hope a good number of English birdwatchers decided to spend a few days in Scotland over the survey period.  Three-quarters of the open coast in the UK is in Scotland (all those crinkly bits, sea-lochs and islands) with Northern Ireland, England and Wales respectively having approximately 2.3%, 16.0% and 6.6%.  Taking account of the spread of the available sites, there’s a relatively uniform UK-wide distribution of most species, although  Sanderling has a southerly bias to its distribution and Purple Sandpiper a strong northern bias.

NEWS-III was not just about waders; volunteers were asked to record other waterbirds too. Our counts for NEWS-II covered Cormorant and Shag, Mute Swan, Eider, Red-breasted Merganser, Wigeon, Mallard, Guillemot and Grey Heron.

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Data from BTO ringing report

Whilst I was delighted to use WaderTales to promote NEWS-III, there was an ulterior motive. We wanted counters to look out for Oystercatchers wearing colour rings. Icelandic Oystercatchers can be encountered almost anywhere but the ones in England are very much outnumbered by those from Norway, the other main source of wintering birds. The table alongside gives an idea of the north-westerly distribution of birds with an Icelandic origin.

oycmap.pngColour-ringed Icelandic Oystercatchers are part of a new project to look at how climate change might be affecting migration patterns. There’s a blog about the project here. The map alongside shows where colour-ringed birds from the study areas in Iceland have already been found, with most in Scotland and Ireland.  Birds will either be wearing 3 colour-rings and a green or white flag or two colour-rings and an engraved darvik.

NEWS only happens every few years so this was a great opportunity to contribute to our understanding of the conservation status of some important species, several of which are now near-threatened. I am looking forward to the results with interest, and a little concern.


 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