Fennoscandian wader factory

 

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Nesting Temminck’s Stint – the smallest of the 22 wader species for which trends are reported

At the end of the summer, vast numbers of waders leave Norway, Sweden and Finland, heading southwest, south and south-east for the winter. In a 2019 paper by Lindström et al, we learn what is happening to these populations of Fennoscandian breeding species, as diverse as Temminck’s Stint and Curlew. The news for the period 2006 through to 2018 is basically pretty good – most populations have been stable and there are even some that have increased – but there are worrying signs for Broad-billed Sandpiper, Red-necked Phalarope and Whimbrel.

Breeding waders of Fennoscandia

blog mapAs a volunteer taking part in the Breeding Bird Survey (BTO/JNCC/RSPB) in the UK, I feel that I do my bit to monitor what is happening to local bird population – providing counts that build into national trends. The work involved in delivering indices for breeding waders across the area of Fennoscandia shown in the map is in a different league. Here, counters visit habitats as diverse as forests, wetlands, mires and tundra, within the boreal and arctic areas of Norway, Sweden and Finland. Some survey sites are so remote that access requires the use of helicopters.

Fennoscandia provides important breeding areas for a large set of wader species, and models suggest that these habitats may be particularly vulnerable to climate change, especially increasing summer temperatures. The 2006-18 analysis in Wader Study, the journal of the International Wader Study Group, presents population trends for 22 wader species. The trends are based on 1,505 unique routes (6–8 km long), distributed over an area that’s about four times that of the United Kingdom. 

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The surveys took place across the whole of Norway and Finland, and in the northern two thirds of Sweden, between 58°N and 71°N, which largely coincides with the boreal, montane and arctic regions of Fennoscandia. The systematic distribution of these routes ensures that the main habitats in these countries are sampled in proportion to the area they cover. The paper describes the methodologies used in the three countries and the way that data were combined, especially factors used to translate sightings of individuals into ‘pair-equivalents’.

Overview of results

blog mountainLooking at the results from across Norway, Sweden & Finland:

  • In terms of pure numbers, Golden Plover was the most commonly encountered wader species, followed by Wood Sandpiper, Snipe, Greenshank and Green Sandpiper.
  • The five most widespread species, seen on the highest number of routes, were Snipe, Green Sandpiper, Greenshank, Wood Sandpiper and Common Sandpiper.
  • Wader species richness and the total number of wader pairs were both higher with increasing latitude; the median number of wader pairs per 10 km increased from just below 3 at latitudes 58–60°N, to just above 26 at latitudes 69–71°N.
  • Using a multi-species indicator, the research team found no general change in wader numbers over the period 2006-18.
  • The trends were significantly negative for three species: Red-necked Phalarope (-7.9% per year), Broad-billed Sandpiper (-5.4% per year) and Whimbrel (-1.3% per year).
  • The trends were significantly positive for three species: Oystercatcher (+4.9% per year), Dunlin (+4.2% per year) and Wood Sandpiper (+0.8% per year).
  • There was no significant trend for another 16 species for which encounters were deemed to be frequent enough for analysis.
  • Population trends of long-distance migrants tended to be more negative than those of medium-distance migrants. This is discussed in detail in the paper.

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Focusing on some key species

The Lindström et al paper is a tremendously rich source of information and references. Here are some species-specific highlights.

Oystercatcher. In the context of a species that is declining across NW Europe, the fact that there is a significant increase in Oystercatchers across Fennoscandia may be surprising. However, the authors note that there was a jump in numbers between 2006 and 2007 with little change since then.

blog l graphLapwing. The trends within the three Fennoscandian countries are very different. In Norway, there has been a dramatic decline (-15.2% per year during 2006–2018) and the Lapwing is now nearly extinct in many areas. The trend in Sweden is also significantly negative (-5.8% per year). In Finland, however, where the species is more widespread and numerous, there has been a strong increase (+5.9% per year) during the same period. See figure alongside.

Golden Plover. No significant change overall. There are some country-specific differences in trends, with a moderate decline in Norway being countered by a moderate increase in Sweden. 

Snipe. The overall trend of this species for each country indicates an initial decline followed by an increase. A similar pattern has been noted in the UK’s Breeding Bird Survey over the same period. 

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Nesting Whimbrel

Woodcock. The trend for 2006–2018 is basically stable and similar in all three countries.

Curlew. There is no significant trend, overall, but populations in Norway and Sweden have declined at the same time that numbers in Finland have increased.

Whimbrel. Fennoscandian trend indicates a decline of 1.3 % per year. Whimbrel is doing poorly in Norway and Sweden but better in Finland. 

Wood Sandpiper. This widespread species has increased slowly (0.8% per year), a trend that is largely driven by Norwegian and Swedish populations.

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Wood Sandpiper was the second most commonly encountered wader

Redshank. The fact that no change was discernible, suggests that boreal and arctic populations are faring much better than the breeding populations further south in Europe. For example, see Redshank – warden of the marsh.

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Redshank – more obvious than most breeding waders encountered!

Spotted Redshank. The estimated annual decline for Spotted Redshank is 2.8% per year but the species is too thinly spread for this to provide significant evidence of a decline. This rate is very similar to the recent drop in the Wetland Bird Survey index in the UK. See Fewer Spotted Redshanks.

Broad-billed Sandpiper. This species has the second most negative trend among the 22 species analysed (-5.6% per year). The bulk of information comes from Finland where the trend is even more negative (-7.5% per year). Birds head southeast in the autumn to countries bordering the Indian Ocean – areas for which winter trend data are not available. The species is still considered to be of ‘least concern’ but perhaps this designation may need to be revisited?

Dunlin. Breeding birds in the survey area are largely of the alpina race. The overall trend is significantly positive (+4.1% per year), which is in sharp contrast to the strong declines of the schinzii subspecies that breeds around the Baltic Sea, western Finland and further south and west in Europe.

blog rnpRuff. There were major declines in the period immediately prior to this review (Lindström et al. 2015) but changes reported here are lower (-2.3% per year) and the decline is not statistically significant.

Red-necked Phalarope. The authors write, “This species has the most negative trend of all the 22 species [-7.9% per year], with most data coming from Sweden. We do not know the cause of this decline but, given that this species shares its south-eastern migration route with Broad-billed Sandpiper, whose population exhibits the second largest decline, the relevant problems might largely apply somewhere along the migration routes”.

Link to Britain & Ireland

As shown in Which wader when and why? there are strong migratory connections between Fennoscandia and the British Isles. Some waders, such as Green, Common and Wood Sandpipers, pass through on their way south in the autumn, whilst many more fly here for the winter, to take advantage of the warmer maritime climate.

Three wader species with particularly strong links between Fennoscandia and Britain & Ireland are still shot and eaten in these islands. Each autumn, large numbers of Woodcock, Golden Plover and Snipe cross the North Sea. It is difficult to ascertain figures for the number that are shot but there is agreement that the vast majority are winter visitors, as opposed to native birds. The results presented in the paper suggest that there have been no discernible changes in the Fennoscandian populations of these three game species in the period 2006-18. Two earlier WaderTales blogs focus on Woodcock and Snipe in Britain & Ireland:

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There has been no significant change in Golden Plover numbers across Fennoscandia

Two WaderTales blogs about wintering waders in Great Britain and the island of Ireland were published in 2019, based on reviews in British Birds and Irish Birds. These were Do population estimates matter? and Ireland’s wintering waders. The six big losers, in terms of wintering numbers in these islands, were Knot, Oystercatcher, Redshank, Curlew, Grey Plover and Dunlin. Knot arrive from Greenland and Canada, with Grey Plover flying from Russia, but it is interesting to think about this Fennoscandian breeding analysis in the context of winter losses of the other four species.

  • Wintering numbers of Oystercatchers have dropped recently in Britain and in Ireland. The population is made up of migrants from Iceland (more about this here), very large numbers from Norway, birds that stay within the British Isles and smaller numbers from other European and Scandinavian countries. Given there is no discernible decline in Fennoscandia, it seems likely that much of the decline can be attributed to a major fall in Scottish breeding numbers (more about this here).
  • Most Redshank wintering in Britain & Ireland are of local or Icelandic origin. Fennoscandian numbers seem to be stable; if there were any changes, these would probably not be apparent in wintering numbers within the British Isles.
  • The Eurasian Curlew has been classified as ‘near-threatened’ and the species is known to be declining in many areas (see this blog about serious problems in Ireland). Ringing shows a particularly strong link between Finland, where breeding numbers seem to be increasing, and Britain & Ireland. The decline in British and Irish winter numbers is probably being driven by lower breeding numbers within the British Isles and in countries such as Sweden, Norway and Poland.
  • There is a theory that new generations of alpina Dunlin may be more likely to winter within Europe’s mainland estuaries, instead of continuing their westward migration across the North Sea. This might explain the apparent anomaly between the 4.1% per annum rise in Fennoscandian numbers and recent winter declines of 3% in Britain and over 20% in Ireland.

Going forwards

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Some of the survey areas were in particularly remote areas

Many of the study squares that were covered during these surveys are a long way from the main centres of human population in Norway, Sweden and Finland. The governments of the three countries are to be congratulated for supporting this important monitoring, which relied on the commitment of hundreds of volunteers. It is to be hoped that these surveys will continue and that further species-focused work will be able to explain some of the differences across Fennoscandia, particularly between eastern and western areas. The rapid declines in numbers of two species that migrate southeast each autumn (Broad-billed Sandpiper and Red-necked Phalarope) highlights the need for better information about what is happening on the flyway linking Fennoscandia with the Arabian Sea and coastal countries of the Indian Ocean.

Paper

Population trends of waders on their boreal and arctic breeding grounds in northern Europe: Åke Lindström, Martin Green, Magne Husby, John Atle Kålås, Aleksi Lehikoinen & Martin Stjernman. Wader Study 26(3)

Click on the title of paper to access it on the International Wader Study Group website. Paper is only available to members of IWSG. If you have read the whole of this blog you’ll probably want to join!

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Nesting Bar-tailed Godwit in smart summer plumage


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.

 

 

Sixty years of Wash waders

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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
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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

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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.
  • The dot in Siberia looks odd but isn’t. This will be a bird of the canutus race, small numbers of which pause on the Wash in autumn and spring, on their way between the Russian Arctic and west Africa.
  • 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

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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

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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:

*Clive Minton died in a car crash a few months after this blog was written. Friends and colleagues have shared some wonderful memories on the IWSG 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

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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

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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).

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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.

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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.

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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.

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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).

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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

Do population estimates matter?

blog top godwitsThis month (March 2019) saw the publication of Population estimates of wintering waterbirds in Great Britain, which includes all the wader species from Little Stint to Curlew. Given that the Wetland Bird Survey already covers about 2000 wetlands and provides annual monitoring, why do we need to know the total number of birds in Great Britain?

I suggest four reasons:

  • If we count the number of Curlew and we have a figure for the European population then we know that Great Britain is responsible for nearly 20% of Europe’s Curlew each winter, thereby strengthening the case for national conservation action;
  • If we have a national figure, then we know that a flock of 2000 Black-tailed Godwit represents (as it turns out) over 5% of the British total, which is a useful criterion when assessing the conservation importance of individual sites;
  • blog GKPopulation totals help to put annual percentage changes into context;
  • And simply because people ask questions such as “how many Greenshank are there in the country during the winter?”

So, here’s the bottom line. In their 2019 review of waterbird numbers in British Birds, a team from BTO, WWT, JNCC & RSPB reveal that an estimated total of 4.9 million waders spend the winter in Great Britain. That’s about one third of all waders on the East Atlantic Flyway. Impressive!

Please note that Northern Ireland figures are included in an upcoming report for the island of Ireland.

Making the counts

The population estimates owe a lot to those who undertake monthly Wetland Bird Survey (WeBS) counts on estuaries, lakes and waterways, during the winter months, year in and year out. Counts from the period 2012/13 to 2016/17 are used in the population estimates that form the basis for the 2019 review. WeBS data have many other uses, as you can read here: Wetland Bird Survey: working for waders.

blog CUFor species of wader that also make use of the open coast, the Non-estuarine Waterbirds Survey of 2015/16 (or NEWS III) provided additional data, updating the NEWS II figures from 2006/07. The vast majority of our wintering Purple Sandpipers are found on open beaches and rocky shores, as well as large numbers of Turnstone, Ringed Plover and Sanderling, together with significant numbers of Oystercatcher, Curlew and Redshank. There’s more about NEWS in this slightly dated blog: NEWS and Oystercatchers for Christmas.

The last assessment of winter wader populations was made by the Avian Population Estimates Panel and published in British Birds in 2013 as Population estimates of birds in Great Britain and the United Kingdom (APEP3). In here, estimates for waders were largely based on WeBS data for the period 2004-09 and NEWS II. The new assessment is presented as Population estimates of wintering waterbirds in Great Britain and also published in British Birds. It uses WeBS information for the period 2012-17 and NEWS III data. Effectively, there is an 8-year or 9-year difference between the two sets of figures.

The biggest losers

blog graphicGreat Britain is extremely important in the context of the East Atlantic Flyway, as is obvious from the fact that the area holds nearly five million waders. The WeBs counts already monitor the ups and downs on an annual basis but this review provides an opportunity to turn the percentages into actual numbers. It is concerning that, over a period representing less than a decade, the average maximum winter count for six of the species that were surveyed dropped by a total of over 150,000. These big losers were Knot, Oystercatcher, Redshank, Curlew, Grey Plover and Dunlin, ordered by number of birds lost, with Knot seeing the biggest absolute decline.

In preparing the new estimates for the British Birds paper, an opportunity was taken to refine the way that populations are calculated, based on Use of environmental stratification to derive non-breeding population estimates of dispersed waterbirds in Great Britain, by Verónica Méndez et al. The new methodology explains some of the differences between percentage changes reported by WeBS and the percentage changes obtained by comparing the latest population estimates to those in APEP3.

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The Knot estimate dropped from 320,000 to 260,000. This figure is higher than might be expected from the counts that take place at sites covered by WeBS, being larger than the ten-year decline of 14% reported in the last WeBS report. Knot are mobile species within the North Sea and Atlantic Coast wintering area and it is possible that British losses may be explained, at least to some extent, by redistribution.

blog oyc graphThe drop in Oystercatcher numbers from 320,000 to 290,000 appears to be less than 10%, compared to a ten-year decline of 12% on WeBS. Improved analysis of NEWS data helped to add some more birds to the open-coast estimate so the 10% fall may underestimate the seriousness of the Oystercatcher situation. The 25-year Oystercatcher decline on WeBS is 26%, which is not surprising if you look at the changes to breeding numbers in Scotland, where most British birds are to be found. There’s more about this in: From shingle beach to roof-top.

blog RKThe Redshank decline of 26,000 is higher than would be predicted from WeBS figures, suggesting a drop of over 20% since APEP3, rather than ‘just’ 15% for the ten-year WeBS figure. This is a species that also features strongly in the Non-estuarine Waterbird Survey and that might explain the difference. Wintering Redshank are mostly of British and Icelandic origin, with the Breeding Bird Survey (BBS) suggesting a ten-year decline of 24% in our British breeding birds.

The Curlew is now globally recognised as near-threatened. The latest winter estimate is 120,000, down from 140,000 in APEP3. The new total represents between 14% and 19% of the European population, which means that we have a particular responsibility for this much-loved species. Only the Netherlands holds more wintering Curlew than Great Britain. Is the Curlew really nearly-threatened? is one of several blogs about Curlew in the WaderTales catalogue at www.wadertales.wordpress/about .

blog 2 DNIt has been suggested that the long-term declines of Grey Plover and Dunlin  may be associated with short-stopping, with new generations of both species wintering closer to their eastern breeding grounds than used to be the case. WeBS results indicate a 31% drop in Grey Plover and a 42% drop in Dunlin, over the last 25 years. There was a loss of 10,000 for both species between APEP3 and the new review, representing declines of 23% and 3% respectively.

The biggest winners

There are four big winners in the period between APEP3 (2004-09) and the new review (2012-16), although, even here, not all as it seems.

The Avocet has seen further dramatic gains. with the estimated wintering population rising to 8,700. The increase is not quite as big as might have been expected, based on the 43% rise seen in ten years of WeBS counts, but it is still a dramatic continuation of a 40-year trend.

The numbers of Bar-tailed Godwit and Ringed Plover are both substantially higher but at least a proportion of each of these changes is linked to the better coverage and more sophisticated sampling methods that were discussed earlier. Bar-tailed Godwit increases may also reflect redistribution around the North Sea.

blog BW graphOne of the consequences of improved statistical techniques, as used this time around, is the apparent decline in the estimated population of Black-tailed Godwit. The new figure of 39,000 is 4,000 smaller than in APEP3, despite the fact that the WeBS graph clearly shows an increase. Interpolation using WeBs figures suggests that the earlier population estimate should have been 31,000, rather than 43,000.

There are other winners too, as you can read in the paper. At the start, I posed the question “how many Greenshank are there in the country during the winter?”.  The answer is 810, representing an increase of 200 since APEP3.

Game species

The estimates for the three wintering waders that are still on the UK quarry list have not changed since APEP3 (published in 2011) as there are no new data available.

Golden Plover: The winter estimate remains as 400,000, as there has been no comprehensive, winter survey since 2006/7. Large numbers of Golden Plover arrive from Scandinavia, Europe and Iceland in the late summer, joining the British birds that choose not to migrate south or west. The GB breeding population is probably less than 50,000 pairs. Most breed in Scotland which has seen a breeding decline of 23% in the period 1995 to 2016 (BBS). Golden Plover is still ‘green listed’.

snipe-headerSnipe (Common): The winter estimate remains as 1,100,000 – a figure that was acknowledged in APEP3 as being less reliable than that of most species. At the same time, the GB breeding population was estimated as 76,000 pairs, indicating at least a 4:1 ratio of foreign to British birds, and that does not take account of the number of British birds that migrate south and west. Snipe are ‘amber listed’ but BBS suggests a recent increase of 26% (1995-2016). There is a WaderTales blog about  Snipe and Jack Snipe.

Woodcock: The winter estimate remains as 1,400,000 – another figure that is not considered to be particularly precise, with much variation between years. The diminishing breeding population is dwarfed by winter numbers, as you can read in this WaderTales blog, with increased attention being given to ways to afford better protection of red-listed, British-breeding birds.

January counts

blog BTThe paper in British Birds also includes a table of January population estimates, to provide data that are comparable to mid-winter counts in other countries. These figures are used in waterbird monitoring for the International Waterbird Census for the African Eurasian Flyway. The main table (and figures mentioned above) are average maximum winter counts (in the period September to March). Black-tailed Godwit is one species that illustrates the difference, with a mean of 30,000 in January and a mean peak count of 39,000. Having moulted in Great Britain, some Black-tailed Godwits move south to France and Portugal in late autumn, returning as early as February. January counts are therefore substantially lower than early-winter and late-winter counts. There is more about the migratory strategy employed by Black-tailed Godwits that winter in southern Europe in Overtaking on Migration.

Looking forward

blog BB coverThe authors have done a tremendous job. They have refined the way that estimates are calculated, they have combined the results from WeBS and NEWS III, and they have delivered population estimates for 25 wader species and many more other species of waterbirds. These population estimates will be used in conservation decision-making until the next set of numbers becomes available. Meanwhile, thousands of birdwatchers will count the birds on their WeBS patches in each winter month, every year. Without them, this paper could not have been written.

Before the next assessment, there will need to be another NEWS survey, to check up on species that use rocky and sandy shore birds, such as Purple Sandpipers, Turnstone and Curlew. Hopefully, there will also be a dedicated survey to assess Lapwing and Golden Plover numbers and perhaps we might find a way to refine the old estimates for Woodcock, Snipe and Jack Snipe.

Paper

Population estimates of wintering waterbirds in Great Britain. Teresa Frost, Graham Austin, Richard Hearn, Stephen McAvoy, Anna Robinson, David Stroud, Ian Woodward and Simon Wotton. Published in British Birds Volume 112. March 2019.

British Birds is a subscription journal. The issue containing this paper can be purchased separately. At some stage, the paper will become free-to-view.

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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

Designing wader landscapes

blog whimbrelMuch has been written about the negative impacts of agriculture on breeding birds – but farming can be good for some species. In Iceland, where high-input agriculture is relatively recent, breeding waders are commonly found in nutrient-rich environments that are associated with increased production. How can high breeding densities of waders be maintained, as farming continues to expand and intensification increases?

In her paper in Agriculture, Ecosystems & Environment Lilja Jóhannesdóttir investigates the distribution of breeding waders across landscapes with varying amounts of highly-cultivated fields and semi-natural areas. She discovers that, in some circumstances and at an appropriate level, adding cultivated land within a broader mosaic of habitats may benefit breeding waders. Is this a model system that provides clues as to how to design landscapes that can support sustainable breeding wader populations in other parts of the world?

The waders of Iceland

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Breeding populations of waders in Iceland (AEWA report)

Iceland is a hot-spot for breeding waders, holding half or more of Europe’s Dunlin, Golden Plover and Whimbrel, in a country that is a bit smaller then England. The paper at the heart of this blog is written by Lilja Jóhannesdóttir, who worked with colleagues from the University of Iceland, the Agricultural University of Iceland, the University of East Anglia (UK) and the University of Aveiro (Portugal). They investigated how different ways of increasing agricultural productivity might impact upon these species, and others such as Black-tailed Godwit, Redshank and Snipe.

Much of Iceland’s upland interior is not suitable as farmland but there is still plenty of room for agricultural expansion. Only 7% of the area between sea level and an elevation of 200 m is currently under cultivation but it is estimated that it would be possible to increase this to 63% – an eight-fold extensification. Icelandic lowlands currently comprise a fine-scale mosaic of open semi-natural habitats and cultivated fields (primarily for silage production to feed animals), making most of the landscape much more heterogeneous than in countries with a longer history of commercial farming.

blog hay and semi-naturalTwo previous WaderTales blogs have already shown that:

Given that farm production is predicted to increase, that farmers like breeding waders and that some intensively-managed fields can be attractive to waders, is it possible to design farmed landscapes that will work for birds and farmers?

Increasing inputs and reducing heterogeneity

blog nice wetlandGlobally, the expansion and intensification of agriculture has altered landscapes and the associated homogenisation has greatly influenced bird abundance and reduced biodiversity. Populations of numerous species, particularly specialist species, have declined, as agriculture has expanded, while generalist species have often thrived in agricultural habitats.

There is no shortage of examples in which highly intensively managed farmland is shown to be bad for breeding waders. In the monoculture hay-meadows of the Netherlands, Black-tailed Godwit productivity is really low, for instance. These fields have been drained, fertilised and re-sown, in order to create easily-managed carpets of single-species grass that can be cut several times a year. There is more about this in this paper by Roos Kentie.

blog hay fieldAlthough there are some areas of Iceland in which farming is quite intensive, there are many others where farmers have a lighter touch. For instance, nutrient-poor dwarf birch marshes may occasionally be grazed by sheep in the summer but these areas have never received applications of artificial fertiliser. At this end of the intensification continuum, increasing agricultural operations may have benefits for breeding waders. When a patch of rough grazing is ploughed and turned into a hay meadow, the addition of fertilisers can potentially increase soil fertility and create an attractive place for waders to feed. A hay meadow within a local area that is dominated by dwarf birch marsh could effectively increase the heterogeneity (& nutrient-richness via spill-over) of the local area, albeit in an artificial way. In the UK, Golden Plovers breeding on moorland are known to travel up to 7 km to feed on fertilised hayfields with high earthworm densities. This paper by James Pearce-Higgins & Derek Yalden in IBIS provides a nice example of how low intensity agriculture can provide resources for waders in the wider landscape.

Researching waders and landscapes

blog dbmLilja’s work in the Southern Lowlands of Iceland focused upon understanding how agriculture influences breeding wader densities and how these relationships might influence future change. At its heart were counts of adult waders encountered along 200 transects (totalling over 100 kilometres) within semi-natural habitats, visited at several stages during the breeding seasons of 2011 and 2012.

As well as counting birds, Lilja categorised habitats within 500, 1000, 1500 and 2500 metres of the transects, which she called buffer area in the paper. Interestingly, and usefully for later analyses, the distribution of different habitat types is pretty uniform across these scales, in this part of Iceland, with little substantial difference according to elevation. In the diagram below, the 200 transects (a) have been split between those below 50 m above sea level (b) and those higher than 50 m (c).

buffers

Landscape-scale effects

To fulfill the various demands of parents and their offspring, waders need diverse resources on or near their territory. An adult can feed a kilometre or more away from its nest, between incubation bouts, and chicks are mobile from an early age. Tagging has shown that young Black-tailed Godwits can move up to 3 km in the first five days of life, just to give one example. In this open landscape, breeding success is likely to be a function of habitat availability at a broad scale. This is explored in a WaderTales blog about nesting Whimbrel.

blog redshankUsing data collected from these 200 lowland transects, Lilja was able to establish relationships between breeding wader densities and the amount of cultivated land and wetland in the surrounding landscape. These two habitat types were considered because future agricultural expansion is likely to take place on drained wetlands that have high conservation value. In her analyses she assessed the extent to which the amount of cultivated land in the surrounding landscape affects wader densities on semi-natural land, and then considered the potential effects of future agricultural expansion on wader populations. There was substantial variation in the density of all of the six most common wader species recorded on the transects, ranging from 0 to 284 birds/km2.

Lilja found that wader densities in semi-natural habitats were consistently greater when the surrounding landscapes had more wetland, at scales ranging from 500 m to 2500 m, indicating the importance of wetland availability in the local neighbourhood. However, the effects of cultivated land in the surrounding landscape varied with fertility and landscape structure, which was largely defined by altitude.

  • In fertile, low-lying coastal areas (from sea-level to 100 m altitude), wader numbers declined with increasing amounts of cultivated land (and the lowest densities occurred in areas dominated by cultivation). This suggests that further conversion of semi-natural habitats into farmland is likely to severely impact waders in low-lying areas.
  • In less fertile habitats at higher altitudes (between 100 m and 200 m), the lowest densities occurred in areas without cultivated land. This suggests that additional resources provided by cultivated land may have a more positive affect in the less-fertile, higher altitude areas.

blog blackwitThe relationships between the areas of wetland and agriculture in the surrounding landscape and the density of waders vary between species, as you can read in some detail in the paper. A few highlights are:

  • With increasing area of cultivated land, densities of Golden Plover, Dunlin and Whimbrel declined significantly at lower altitudes but increased at higher altitudes. These are the three species that would appear to respond most positively to the addition of pockets of cultivated land within a semi-natural matrix of less fertile land, that tends to be found at higher elevations.
  • Higher amounts of wetland were associated with increased densities of Dunlin and Black-tailed Godwit, but lower densities of Redshank. Golden Plover numbers were unaffected by amount of wetland in the surrounding landscape.
  • Whimbrel densities increased with wetland area, at higher altitudes. Wet patches have been shown to be very important to Whimbrel chicks, as you can read in this WaderTales blog about research in Shetland.
  • At lower altitudes, Snipe densities increased with the amount of wetland area in the local vicinity. This relationship was less pronounced at higher altitudes, which tend to be less effectively drained and hence generally wetter.

dunlin graphic

What now?

Changes in Icelandic landscapes are to be expected in the coming years, as most farmers intend to increase their areas of cultivated land. This expansion will inevitably have impacts upon the internationally important breeding wader populations of Iceland but the level of such impact will depend on where the expansion will occur. This paper shows that increases in the area of cultivated land at lower altitudes in Southern Iceland are more likely to result in declines in wader density than in less fertile areas, when tend to occur at slightly higher altitudes (still under 200 m above sea level). An important next step will be to identify the landscape structures and scales of management that can continue to support high densities of breeding waders.

blog coastal wetlandGiven the international importance of Iceland as a home for breeding waders it would be nice to think that this paper can be used to develop national land management policies that can prevent the unintended loss of species such as Golden Plover and Snipe, which landowners value and wish to preserve. At the farm and community level, the paper highlights the key importance of maintaining the complex and heterogeneous landscapes of lowland Iceland, retaining as many as possible of the remaining wetland patches and pockets of semi-natural land within even the most intensive of farming areas.

The paper may well be of interest to conservationists who are struggling to reverse wader declines in other parts of the world. In Southern Iceland, where 7% of the land is being farmed relatively intensively within a fine scale mosaic of both wet and dry semi-natural habitats, it is possible to support hundreds of waders per square km across the wider countryside. Can this situation be replicated across large tracts of land in other countries?

Take home message and paper

blog heterogeneousThis paper provides a useful reminder that the links between land use changes and biodiversity implications can be highly context-dependent. Further agricultural conversion of wetlands and rough grazing areas in the fertile low-lying areas of Iceland is likely to be detrimental for breeding waders, but such effects may be less apparent in less fertile, higher altitude areas. Here, the conversion of some land from rough-grazing to hay meadows may provide feeding opportunities off-territory for Dunlin, Golden Plover and Whimbrel. The scale at which the addition of cultivated areas is beneficial to breeding waders has yet to be determined.

This paper is published as:

Interacting effects of agriculture and landscape on breeding wader populations. Lilja Jóhannesdóttir, Jennifer A. Gill, José A. Alves, Sigmundur H. Brink, Ólafur Arnalds, Verónica Méndez and Tómas Grétar Gunnarsson https://doi.org/10.1016/j.agee.2018.11.024

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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.

 

Farming for waders in Iceland

Across the world, agriculture is one of the primary threats to biodiversity, as we tear up natural environments to create more space to feed an ever-growing and increasingly meat-hungry human population. Agricultural land can, however, also provide key resources for many species whose behaviours align with the rhythms of the farming year.

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In Iceland, farming areas support large and important populations of several wader species, including 75% of Europe’s Whimbrel and over half of Europe’s Dunlin. As the country welcomes more tourists and expands the range of crops grown for food and fuel, what might be the implications for iconic species such as Whimbrel, Dunlin and Black-tailed Godwit?

This paper by Lilja Jóhannesdóttir, of the University of Iceland, and colleagues there and at the universities of Aveiro (Portugal) and East Anglia (UK), investigates the use of farmland by waders living in a semi-natural landscape.

Paper details: Use of agricultural land by breeding waders in low intensity farming landscapes Lilja Jóhannesdóttir, José A. Alves, Jennifer A. Gill, & Tómas Grétar Gunnarsson Animal Conservation. doi:10.1111/acv.12390

A dynamic landscape

blog snipe postIn Iceland, volcanic activity poses serious short-term threats to agriculture, especially in areas close to the mid-Atlantic ridge, which runs through the island from south-west to north-east. Threats from volcanoes include ash-fall, lava, flooding of glacial rivers and earthquakes but, on the plus side, nutritional inputs from volcanoes have beneficial effects on soil fertility in these central areas. Over time, and with the assistance of wind and water, many of these nutrients collect in the lowlands of the country – the areas that now form the main agricultural areas, especially in the warmer south.

The distribution of breeding waders varies across lowland Iceland. A survey carried out between 2001 and 2003 showed that wader densities were greater in areas of the country that had been subject to higher rates of volcanic ash deposition with, for instance, three times as many waders in the south as in the west. See How volcanic eruptions help waders. As was shown in the paper at the heart of that blog, the nutrient signal associated with ash-fall breaks down in farmland. Here, perhaps as a consequence of the application of natural and artificial fertilisers over decades or even centuries, there is no association between ash-fall and wader density. Across the whole country, irrespective of the proximity of volcanoes, nutrient-rich agricultural land attracts waders – but which wader species and across which farmland habitats?

Waders and agriculture

In a previous paper, Lilja Jóhannesdóttir showed that over 90% of Icelandic farmers think it is important or very important to have rich birdlife on their estates, but that farmers also expect to increase the area of farmed land in the coming years. There’s more about this in the WaderTales blog: Do Iceland’s farmers care about wader conservation? It is important to understand the ways that waders currently use farmland, in the hope that nesting waders can continue to be accommodated within the future farming landscape of Iceland.

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Perhaps Oystercatchers think that the fields have been ploughed especially for them?

Agriculture in Iceland is still relatively low in intensity and extent, and internationally important populations of several breeding bird species are abundant in farmed regions. Only about 2% of land is cultivated (about 7% of lowland areas), of which about 85% is hayfields (grass fields managed to produce crops of grass for storage as winter feed) and 15% consists of arable fields (mostly barley). This is similar to areas such as Norway, northern Canada and northern and western areas of the British Isles but contrasts sharply with the US and many countries in the EU which, on average, have 20% or more of their land under cultivation.

In these high-latitude landscapes, agricultural land can potentially provide resources that help to support wader species. To address these issues, Lilja conducted surveys of bird abundance on 64 farms in northern, western and southern areas of Iceland that vary in underlying soil productivity, and quantified:

  • Levels of breeding bird use of farmed land managed at three differing intensities, ranging from cultivated fields to semi-natural land
  • Changes in patterns of bird use of farmed land throughout the breeding season.

Farm survey

In Iceland, there are still large patches of natural or semi-natural habitats; they surround the hay-fields and arable fields that are at the heart of many farms. This arrangement creates gradients of agricultural intensity from the farm into the surrounding natural land, tapering from intensive management to moderate and light management.

BLOG gradient

The three intensity levels within Icelandic farmland can be roughly described as follows:

  • Intensive: Hayfields (85%) and arable fields (15%) fields. Most hayfields are mown twice per year and ploughed and reseeded every few years.
  • Moderate: Old hayfields that are rarely or never mown but are used for grazing, or fertilized grasslands used for livestock grazing.
  • Light: Semi-natural or natural areas under low intensity grazing, usually by sheep or horses, or with no agricultural influence, ranging from sparsely vegetated habitats to habitats with abundant vegetation (where grasses and bushes dominate the vegetation) and with a broad wetness gradient.

Fields corresponding to these three categories were surveyed on the 64 farms, firstly during the egg-laying and incubation period and then later, to coincided with chick rearing.

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Gradient of management from intensive (left) to wet semi-natural (right)

Where were the waders?

blog RK on postLarge numbers of waders were encountered in all transects in all parts of Iceland, with Black-tailed Godwit and Redshank contributing most records. There were also important numbers of Oystercatcher, Golden Plover, Dunlin, Snipe and Whimbrel. Overall, wader densities on farms did not vary significantly between regions or between early and late visits but there were some subtle differences:

  • Wader density varied significantly along the management gradient, with lower densities tending to occur in more intensively managed areas, particularly in the early (nest-laying and incubation) season.
  • Intensively managed fields in the west (where underlying soil productivity is lower) had higher densities of waders than in the north and south of the country.
  • There were seasonal declines in wader density on all three management types in the south, but seasonal increases on intensive and moderate management in the west and in fields under moderate management in the north.
  • There were some differences between species in these patterns (more details in paper).

blog redshank westOne of the interesting differences in the west was the redistribution of Redshank as the season progressed. There were three times as many pairs of Redshank in cultivated land during the chick-rearing period than during incubation, suggesting that adults may be moving broods into cultivated land. Resources for chicks may well be relatively more abundant or accessible in these areas, given the relatively low levels of nutrients in areas that are a long way from the active volcano belt. There’s also a suggestion that drainage ditches around cultivated fields in the west may provide important resources for Snipe.

What about the future?

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Wader densities during the early (red) and later (blue) part of the breeding season (Modified from the paper in Journal of Animal Conservation)

Although the density of birds in Iceland’s agricultural landscapes tends to be higher in lightly managed than intensively managed agricultural land, densities in the areas under the most intense agricultural management are still high, suggesting that agricultural habitats provide important resources within these landscapes (see figure alongside). These density estimates (between 100 and 200 waders/km2) are typically much higher than those recorded in other countries in which these species breed.

Farmers in Iceland expect to expand their cultivated land in the coming years in response to increasing demand for agricultural production (Do Iceland’s farmers care about wader conservation?), and evidence from other countries throughout the world has shown how rapidly biodiversity can be lost in response to agricultural expansion and intensification. Protecting these landscapes from further development is crucial to the species that they support.

The authors suggest ways in which farming practises might change wader distributions in Iceland. Here are a few of the interesting points that they make:

  • When wader-rich semi-natural land is replaced by arable farming and intensively-managed hayfields, this is likely to reduce overall wader densities.
  • Losing wet features, which provide insect food for waders, may well have impacts for chick growth. Here’s a WaderTales blog that discusses the importance of wet features to Lapwings in the UK.
  • In other countries, early grass mowing is a direct threat to nests and chicks. Clutch and brood losses are already being observed in Iceland and, with warmer springs encouraging earlier grass growth, this could become more of a problem.
  • The conversion of less-intensively managed areas into farmland is likely to have most effect on Dunlin, Black-tailed Godwit and Whimbrel, which tend to occur in their highest densities in the least intensively managed lowland areas.

blog walk WhimbrelIt is estimated that between 4 and 5 million waders leave Iceland each autumn, for Europe, Africa and the South Pacific (Red-necked Phalarope). Iceland’s farmland supports many of these birds and this study highlights the need to protect them from the agricultural developments that have led to widespread wader losses throughout most of the world.

You can read the paper here

Use of agricultural land by breeding waders in low-intensity farming landscapes Lilja Jóhannesdóttir, José A. Alves, Jennifer A. Gill, & Tómas Grétar Gunnarsson. Animal Conservation. doi:10.1111/acv.12390

blog oycs & chick

 


 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

 

 

Interpreting changing wader counts

Blog mixed flockWhen you count the number of Redshank on your local estuary and discover that there are fewer now than there were last year –  or five, or twenty years ago – what are the implications? Is this part of a national or international trend or has something changed within the estuary itself?

The first question to ask is, ‘what is happening elsewhere?’ and then to wonder about the ways in which numbers of birds in different sites might relate to each other. What actually happens to local counts when national counts go down – or go up, for that matter?

The UK Wetland Bird Survey (WeBS) data provide comprehensive and long-term monitoring of estuarine wader populations around our coastline. Thanks to volunteers who collect monthly counts each year, these data present an excellent opportunity to explore how bird distributions can change over time. A new paper by Verónica Méndez and colleagues from the University of East Anglia and British Trust for Ornithology uses counts of 19 species (18 waders plus Shelduck, an honorary wader) over a 26-year period to ask what happens to distribution and local abundance across our estuaries when overall population sizes go up or down.

Consequences of population change for local abundance and site occupancy of wintering waterbirds Verónica Méndez, Jennifer A. Gill, José A. Alves, Niall H. K. Burton & Richard G. Davies Diversity and Distributions. 2017;1–12. DOI: 10.1111/ddi.12653

The counters

Blog Counter 2A WeBS count can be a tough assignment for a volunteer birdwatcher. Being allocated to a stretch of an estuarine coastline and asked to visit it, whatever the weather, on a given weekend of every month, in every winter, is not the same as an invitation to go birdwatching in September to look for a Curlew Sandpiper.

The counts used in this paper are from the months of November through to February, when waders are largely settled for the winter and the weather can be less than clement. Many of the data-points for individual sites have been collected by the same person in all of the years analysed in the paper and every contribution is important.

WeBS70logo6a_smallWeBS is the successor of other, similar count schemes which are celebrating 70 years of continuous monitoring this year. It is organised by BTO, in partnership with RSPB and JNCC and in association with WWT. There are over 3000 registered WeBS volunteers, collecting data about the waterbirds that can be found on estuaries, in wetlands, on inland lakes, along river valleys and in local parks and villages.

Understanding change

Many populations of migratory birds are changing in number quite rapidly at present, but are these changes more likely to result in changes in occupancy (eg colonisation of or extinction from some sites) or changes in abundance within sites? Put simply, if extra waders arrive in the autumn, how do they distribute themselves across available sites? If fewer arrive, where will the gaps be found?

DN and BTG graphs

The contrasting fortunes of Dunlin and Black-tailed Godwit over the period covered in the new paper

Over the period studied in the paper (between 1980-85 and 2002-07), populations of five species declined, with the greatest losses occurring in Purple Sandpiper and Shelduck (both declined by about 25%), while there were increases for four, the biggest of which were Avocet (+1690%), Golden Plover (+554%) and Black-tailed Godwit (+418%). No birdwatcher will be shocked by the figures for Avocet or Black-tailed Godwit, wintering numbers of which have shot up, but Golden Plover is more of a surprise and may be linked to a move from inland fields to estuaries.

When the size of a wintering population of waders declined, Verónica Méndez and her colleagues found that the main consequence was a reduction in numbers across all sites. Birds were likely to stay on a site even if local numbers were dwindling. This suggests high levels of site-fidelity by individual waders, which is something we know from ringing and tracking studies. If you’re still alive then just do the same again – there could be a better site with a higher number of conspecifics somewhere else but it would be risky to try to find that out.

 

Blog Avocets

Thirty years ago, few people can have expected that they would ever see such a large flock of Avocets on the Humber

If the size of a wintering population increased, generally numbers went up within all occupied sites. The exceptions tended to occur in species for which original numbers were very small, such as for Greenshank, or species for which the change in numbers has been rapid – as seen in Avocet and Black-tailed Godwit.

If adults don’t change their wintering sites then increases are presumably being driven by juveniles. Their settlement decisions may be influenced by the distribution of adults of the same species, resulting in increased local abundance, rather than colonisation of new sites. For the two rapidly-expanding species, Black-tailed Godwit and Avocet, there was colonisation of 25 and 15 new sites, respectively, between 1980-85 and 2002-07, with some indication of more similar increases in sites that were closer together, which may reflect local movements among groups of nearby sites.

Designating sites

Blog Blackwit

Juvenile waders may well settle in areas where there are already populations of wintering adults

One of the key conservation measures for waders across Europe is the Special Protection Area (SPA) network, a collection of sites that are designated because they hold internationally or nationally important numbers of species, measured as a percentage of the population. Designated sites need to maintain numbers of all the species that hit this threshold percentage. However, if a national or European population gets larger (for example because of high breeding success) but the number on a particular site does not grow (or grows more slowly), then the species might drop below the threshold for protection, even if the site is unchanged. Theoretically this could affect a site’s protected status for that species, although is unlikely to be a problem, as most sites are designated for many species.

This new paper shows that gains and losses tend to be fairly constant across all sites, making it unlikely that a site designation would be affected by national or European-scale changes. In only one species (Ringed Plover), have numbers declined so much in some sites that the total number of sites exceeding the threshold for that species has decreased.

Keep counting!

Blog Counter 1Habitat availability and site fidelity, along with species longevity, may explain the strong tendency for local population abundance to change much more than site occupancy, in our wintering waders. Given the statutory importance of maintaining waterbird populations in designated protected areas, it is important to continue local and national surveys that can identify changes in local abundance and relate these to large-scale processes.

Returning to the earlier question – When you count the number of Redshank on your local estuary and discover that there are fewer now than there were last year –  or five, or twenty years ago – what are the implications?

This new paper shows that it is unlikely that a local drop in a species’ numbers is caused by a redistribution of birds. Factors that might lie behind a local decline need to be investigated locally, if the trend is not replicated elsewhere. The authors could only reach this conclusion because they had 26 years of WeBS data from a range of sites at their disposal. Future generations of WeBS counters will hopefully continue to monitor the conditions of our estuaries, working together throughout the country to interpret local counts within a national framework.

Paper

Consequences of population change for local abundance and site occupancy of wintering waterbirds Verónica Méndez, Jennifer A. Gill, José A. Alves, Niall H. K. Burton & Richard G. Davies Diversity and Distributions. 2017;1–12. DOI: 10.1111/ddi.12653

Blog RINGOS


 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

 

 

Do Iceland’s farmers care about wader conservation?

When working with Icelandic farmers to conserve internationally important wader populations, a shared understanding of beneficial practises may be more important than financial incentives.

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Species like Snipe, Redshank and Black-tailed Godwits have been squeezed out of lowland areas of countries such as the UK and the Netherlands by centuries of drainage, increasingly homogeneous landscapes and the introduction of quick-growing grassland monocultures. Adults have lost nesting sites, chicks have fewer feeding opportunities and pre-fledged youngsters fall victim to farm machinery. Do the same fates await waders in Iceland or might it be possible to work with farmers to leave space for birds?

b-pool

Pools, set within semi-natural lightly-grazed fields, are important

As part of her PhD at the University of Iceland, in collaboration with the Universities of East Anglia (UK) and Aveiro (Portugal), Lilja Jóhannesdóttir asked farmers what they think about having birds on their land, what their plans are for their farms, whether they might be willing to leave some pools and focus farming activities in areas less important for birds, and if farm subsidies might encourage them to be more proactive conservationists. The sometimes surprising results of this questionnaire have been published in Ecology & Society.

Reconciling biodiversity conservation and agricultural expansion in the subarctic environment of Iceland. Lilja Jóhannesdóttir, José A. Alves, Jennifer A. Gill  and Tómas G. Gunnarsson. Ecology and Society 22(1):16.

The Waders of Iceland

tableIn a recent report prepared by AEWA (Agreement on the Conservation of African-Eurasian Migratory Waterbirds), in response to concerns about the effects of afforestation on Iceland’s waterbirds, Dave Pritchard & Colin Galbraith say “Iceland is second only to Russia in its importance as a breeding ground for migratory waterbirds in the AEWA region. It supports the most important breeding populations in Europe for six species of waders, and is the second most important country for three.”

Data in the table alongside have been extracted from Annex 4 of their report, which was discussed at the 12th Standing Committee of AEWA in Jan/Feb 2017. Iceland is home to c 75% of Europe’s breeding Whimbrel, over half of the area’s breeding Dunlin and perhaps half of its Golden Plover. The importance of Iceland has increased with the collapse of wader populations in other countries.

Waders on farmland

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Spring flock of Black-tailed Godwit feeding in a stubble field

Farmed landscapes in Iceland provide opportunities for waders. In the spring, newly-arrived flocks of Golden Plover spread out over hayfields, Black-tailed Godwits target the previous year’s barley stubbles and parties of feeding waders can be seen in sedge pools on farms. During the breeding season, the application of fertilisers, especially in areas where volcanic ash deposition is low, increases soil productivity and wader densities, as was shown in this blog about regional productivity. Come the autumn, hayfields attract flocks of birds fattening up for migration. Despite drainage of an estimated 55% to 75% of wetlands in Iceland in the last seventy years, the country is still a great place for waders.

The amount of intensively-farmed land in Iceland is increasing, to some extent driven by rapid recent increases in the number of tourists, who consume milk products and meat. This can be seen in the ongoing development of hayfields, to feed cattle, and barley production, for pig-feed. There is concern that these developments will impact upon wader numbers, through the reduction in the amount of semi-natural habitat, especially in the lowlands, loss of pools and reduced landscape heterogeneity. On top of these changes, warmer temperatures allow earlier cuts of silage which increases the risk of killing wader chicks that nest within these fields.

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More and more semi-natural land is being lost to grass monocultures

Lilja Jóhannesdóttir’s PhD is focused on how birds use the gradient of habitats that comprise farmland in lowland Iceland – from more intensively farmed fields through to lightly-grazed, semi-natural habitats. The paper that forms the focus of this blog looks at farmers’ attitudes to the birds that share Iceland’s farms and their plans for the future. It then attempts to reveal the willingness and capacity of landowners to engage with conservation management practises.

The questionnaire

To understand the views of Icelandic farmers toward bird conservation, given the current potential for agricultural expansion, Lilja interviewed 62 farmers across Iceland, using a structured questionnaire. Some of the key findings are:

  • Over 60% of farmers are likely or very likely to increase their area of cultivated land
  • Over 90% of farmers think it is important or very important to have rich birdlife on their estates
  • About 60% would consider modifying grazing regimes to help birds
  • More than 80% would be unlikely or highly unlikely to consider changing the timing of harvesting operations.
  • More than 80% would be happy to consider keeping pools intact
  • Information on conservation needs are more likely to change attitudes than financial incentives

The information collected in the questionnaires was analysed by region and by the age of the interviewee but no strong patterns emerged. Older farmers seem to appreciate birdlife more than their younger colleagues but are no more likely to change their behaviours to support conservation objectives. The detailed figures are reported in the paper.

b-dunlin

Creating new hayfield to produce cattle-food is at the expense of areas of semi-natural land

The majority of the Icelandic farmers who took part in the survey plan to expand their agricultural land in the next five years, and this is likely to be driven further by increasing demands for farming products. This implies that conversion of semi-natural land into farmland is likely to greatly increase in the near future, with potentially severe and widespread impacts on the internationally important bird populations that currently breed in these areas. Such expansion could put Iceland on a similar trajectory to many other countries that have experienced substantial biodiversity declines on the back of agricultural intensification and expansion. On the positive side, Icelandic farmers like wildlife and the results suggest that if they are better informed about the consequences of their actions they might well try to modify plans in ways that reduce negative impacts. The possibility of financial incentives to off-set potential losses did not seem to influence farmers’ views, but the authors suggest that this might be because there is no tradition for farmers to receive subsidies for conservation action.

b-horsesA clear finding of the study is that farmers are unlikely to change the timing of agricultural operations in order to help birds. Perhaps this is unsurprising in a country with a very short growing season and where periods of settled weather are rare. With relatively few consecutive dry days, opportunities to mow and turn silage or hay crops just have to be taken. The timing of farming operations, such as harvesting/mowing, can be crucial for breeding waders because they can result in the destruction of nests, chicks, and adults during the breeding season. For example, advances in timing of mowing of hayfields in the Netherlands has meant that this now coincides more frequently with wader nesting and chick rearing, causing unsuccessful breeding attempts and leading to lower recruitment. There is more about the Dutch experience in this Ibis paper.

If Icelandic farmers are unlikely to delay operations, perhaps other strategies, such as mowing fields from the centre – as used in the Outer Hebrides to reduce Corncrake losses – might be more acceptable to farmers who are so constrained by the weather? Read more about the Corncrake issue here. 

More blogs about Lilja’s research

In other papers from Lilja’s PhD, we learn about the way that Iceland’s breeding waders make use of opportunities presented in different types of farm landscapes and discover that the effects of increased intensification depends upon where new fields are created.

The Future

b-whimbrelAs a signatory to international agreements on the conservation of birds and wetlands (Ramsar Convention, Bern Convention, Convention on Biological Diversity and African-Eurasian Waterbird Agreement), the Icelandic government is required to take action to protect the internationally important bird populations breeding in the country. Given that there is no strong tradition of using planning laws or centralised agricultural policy to influence farmers’ decisions, working with individual farmers might be the best way to deliver conservation objectives.

Farmers’ views on the importance of having rich birdlife on their land and their willingness to participate in bird conservation provide a potential platform to work with landowners to design conservation management strategies – and to do this before further substantial changes in the extent of agriculture take place in this subarctic landscape. With three-quarters of Europe’s breeding Whimbrel and about half of the Golden Plover and Dunlin dependent upon decisions made in Iceland, there is a lot at stake.

Reconciling biodiversity conservation and agricultural expansion in the subarctic environment of Iceland. Lilja Jóhannesdóttir, José A. Alves, Jennifer A. Gill  and Tómas G. Gunnarsson. Ecology and Society 22(1):16.

b-end


 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

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Tracking waders on the Severn

Birdwatchers are being asked to help with some cutting-edge science, simply by reporting sightings of colour-dyed Dunlin and colour-ringed Curlew and Redshank.

Severn 1 WWT (2)

The Severn: an empty estuary or a food-rich haven? (Corinna Blake)

The tides that create unique feeding opportunities for waders and other waterbirds on the Severn can potentially be harnessed to produce large amounts of clean energy. New impact assessment work aims to see how a development that would bring big benefits to the local economy might be carried out with as little negative environmental side-effects as possible.

Colour ringed Curlew by Kane Brides

Birdwatchers are asked to look out for colour-ringed Curlew and Redshank (Kane Brides)

The Severn is a great place for birds, especially waders, attracted to the area by mud that has high densities of mud-loving invertebrates such as ragworms. It is designated as an SPA, because of its importance to wintering species such as Bewick’s Swan, Curlew, Dunlin, Pintail, Redshank and Shelduck, and the spring passage of Ringed Plovers. There’s more about the SPA on the JNCC’s website.

The British Trust for Ornithology and Wildfowl & Wetlands Trust scientists have been awarded a contract to undertake an Environmental Impact Assessment for the proposed Cardiff Tidal Lagoon  by Tidal Lagoon Power, with BTO focusing on waders and WWT on ducks. It’s a unique opportunity not only to inform conservation planning but also to answer questions about the winter ecology of some key species. The team aims to:

  • Validate and refine methods developed by Richard Stillman (Bournemouth University) that predict bird distributions from food availability. (It’s easier to map food distribution than to follow bird movements)
  • Understand patterns of movement of species that use the proposed development area and other key sites, such as the Gwent Levels.
  • Track birds in order to identify feeding and roosting areas that are used when birds are hard to observe – in poor weather, at night and at all stages of tide.
  • Work out how mobile birds are, in order to propose ways in which lost feeding opportunities might be replicated as close by as possible.

Tagging

Tag on Curlew back (head covered to keep bird calm) by Lucy Wright

Tags like this should reveal how waders and ducks use the Severn estuary. Curlew by Lucy Wright.

Tagging is an important part of the project. Four-gramme Pathtrack tags are being glued to the backs of a sample of Curlew, Redshank, Shelduck and (hopefully) Shoveler. These should stay on for a couple of months, during which time movements will be logged every 90 minutes and downloaded using UHF receiving stations set up around the Severn. These four species have been chosen because, for each, more than 10% of the estuary’s population lies within the proposed footprint of the tidal lagoon.

Colour-rings

Colour ringed Redshank by Emily Scragg

This colour-ringed Redshank may well breed in Iceland but which areas of mud-flat does it use in the winter? (Emily Scragg)

Tagged Redshank and Curlew are also being colour-ringed, alongside others that are not being tagged. By collecting reports of colour-ringed birds from birdwatchers, the BTO team will be able to monitor the efficacy of the tag down-load process and keep a track of movements when the tags stop transmitting. As an added bonus, the colour-rings may generate some new information about the breeding sites of waders that winter on the Severn.

Sightings of colour-ringed birds would be very much appreciated. Five rings have been used on both Redshank and Curlew. Please submit sightings (date time and ideally a six-figure grid reference) to Emily.scragg@bto.org who would also be interested in “ratio counts” of flocks of birds – simply the number of colour-rings and the size of the flock.

Colour-dyed Dunlin

The Severn Estuary holds an estimated 3.2% of the European wintering population of the alpina race of Dunlin, birds that breed from Siberia across to northern Scandinavia. Dunlin are too small to carry transmitters that can be used with base stations so the team has gone back to traditional picric dye in order to look at the mobility of flocks. Any sightings of colour-marked Dunlin will be appreciated by emily.scragg@bto.org. Where possible, please submit ratio counts broken up into yellow/orange on breast (adults), yellow/orange on the rump (juveniles) and unmarked birds, together with date, time and location (ideally with six-figure reference).

Colour-dyed Shelduck

shelduck Kane Brides

The neck of this tagged Shelduck will be dyed yellow before release (Kane Brides)

It’s not just waders.  Over 3,000 Shelduck winter on the Severn, which is more than 1% of the European population. A sample has been caught by WWT. Ringed birds have a yellow/orange dye mark on the normally white plumage on the neck/upper breast (between the dark green head and the brown breast band). No Shoveler have been caught yet but the aim will be to put a similar dye-mark on these birds too.  Sightings of dye-marked ducks should be reported to Ed.burrell@wwt.org.uk

Impact Assessment

The consortium of organisations that is working on this new tidal-power study is well placed to combine impact assessment with high quality wader science. By focusing on Curlew and Redshank, both red-listed species of conservation concerned, it is to be hoped that more will be learnt about the winter feeding ecology of these two species. The BTO team has already discovered that Redshank fly further at night than was previously thought and hope to get to understand some of the pressures facing Curlew, now classified as globally near-threatened (see separate WaderTales blog)

Severn 4 WWT

The Severn – Gareth Bradbury/WWT

This is not the first impact assessment work that has managed to incorporate research that increases the scientific understanding of wader behaviour and ecology. Two other examples are given below:

The Wash: Back in the 1970s, a plan to build huge reservoirs on the mud flats of the Wash, in which to store fresh water that might meet the growing demands of southeast England, led to a doubling of wader catching activity, intensive studies of their feeding ecology and complementary work on other taxa. Much was learned about the mobility of species within this huge estuary and the turn-over of birds within the annual cycle. A draft copy of the report is available on line at the NERC website 

Cardiff Bay: In the period 1989 to 2003, long-term studies took place to try to understand the impacts of closing Cardiff Bay and hence reducing the amount of tidal feeding area for waders. Following the development, it was shown that Redshank that had been displaced from the Bay were in poorer condition and had lower survival rates in subsequent winters.  There’s a summary on the JNCC website. The papers listed at the bottom of this JNCC web-page are essential reading for anyone trying to counter the ‘birds will simply go elsewhere’ arguments, which are sometimes put forward in favour of development work.


 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