25 years of wader declines

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

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

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

map graph

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

In for the long haul

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

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

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

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

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

Where to find waders in Strathallan

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

graphic

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

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

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

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

A changing farmland landscape

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

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

Breeding success

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

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

What is changing?

TGG Oyc

The changing fortunes of Oystercatcher are discussed in this WaderTales blog

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

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

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

A relentless decline

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

Here’s a link to the paper:

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


 GFA in Iceland

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

@grahamfappleton

 

 

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Curlews can’t wait for a treatment plan

Europe is losing 5000 Curlews every year. What can we all do to stop – or even slow down the decline?

RC single bird muddy edgeIf a patient presents with a problem, it’s the job of the health professional to work out the root cause, to come up with a treatment plan and to check that it works. That’s the process that is used for bird conservation – notice, diagnose, treat and monitor. Sometimes, however, the patient is in such a serious condition that you cannot wait for a full set of test results, you just have to try something. That’s the situation with Curlew in the United Kingdom; the losses are so rapid that people are already taking local action to try to increase chick numbers (see some links at the bottom).

This blog focuses on a new paper, by Samantha Franks and colleagues from the BTO and RSPB, that tries to identify the primary factors associated with the species’ decline at a national scale. Unsurprisingly, the answers point to changes in ‘habitat’ and ‘predation’ but it’s worth looking at the detail.

Background

The United Kingdom is one of the key breeding areas for Eurasian Curlew, accounting for an estimated 19-27% of the global population. Within the UK, breeding Curlew numbers have dropped by 48% in the last 20 years – earning the species the dubious distinction of red-listed status in 2015. We are responsible for a staggering estimated loss of 13.5% of the European population during this period.

categoriesThere’s more about the national and international problems for Curlew in this blog (Is the Curlew really near-threatened?). Sadly, the Eurasian Curlew is not alone – almost every member of the Numeniini (curlews, godwits and Upland Sandpiper) is in trouble, as you can read here (Why are we losing our large waders?).

Theories

The aim of the new study by BTO and RSPB scientists is to use national figures to assess whether there is evidence to support or refute previous theories about the causes of Curlew declines. The paper starts with a thorough and fully-referenced overview of existing evidence for potential causes of the population change. At its heart is a discussion as to how management affects Curlews, through things like changes to upland grazing patterns and land-use modifications which may have had unintentionally positive effects on generalist predators. Changes to weather patterns provide additional challenges. The suggested drivers of the declines that have been observed and in some cases measured are summarised here.

Potential positive effects on Curlews:

  • GT inbye

    Adding some improved grassland to the habitat matrix

    Increased fertility of improved grassland could boost invertebrate numbers and support Curlews

  • Gamebird management may provide better habitat conditions for breeding Curlew
  • Site protection might limit development and protect habitat

Potential negative effects on Curlews:

  • Intensification of agricultural activity – e.g. removal of rough, damp patches used by Curlew
  • Conversion of open habitat into woodland may reduce feeding opportunities and harbour predators
  • Increases in numbers of general predators
  • Climate change – warmer summer temperatures/reduced rainfall may change prey availability
  • Declining quality of heaths and bogs may reduce nesting opportunities

Data analysis

BBSThe paper uses data collected by thousands of volunteers who contribute to the Breeding Bird Survey (BBS), organised by the BTO in partnership with JNCC and RSPB. The team focused upon Curlew breeding distributions in Great Britain during the periods 1995-99 and 2007-11, separately. They then considered patterns of change between the two periods.

The following potential correlates of distribution and change were investigated:

  • Changes to habitat – as evidenced from land cover maps
  • Site protection – as included in the World Database of Protected Areas
  • Topography – altitude, slope and organic carbon content of soils
  • Climate – summer and winter rainfall and temperature data
  • Game management – assessed from maps of strip-burning in the uplands and BBS data on gamebird abundance
  • Predator populations – crow and fox data from BBS counts

GT chickSo, how well did the patterns of change fit with the theories as to which factors might be causing the collapse of Curlew numbers? Let’s start with a couple of the strange findings from the 1995-99 period. It illustrates just how hard it is to interpret correlative relationships. Just because A and B happen at the same time, does it mean that A is actually causing B?

1995-99 anomalies

When the research team investigated links between Curlew abundance in 1995-99 and the variables that might explain the species’ distribution, they found that Curlews were associated with semi-natural grassland, heathland and bog, as one might expect. However, Curlew were also more abundant in areas with a greater amount of woodland in the landscape, albeit this being a relatively weak relationship . Given previous research by David Douglas et al in the Journal of Applied Ecology had shown a negative effect of woodland on Curlew abundance, this seemed strange. This unexpected association with woodland was reversed when data for 2007-11 were considered and when the changes between the two periods were analysed. The authors’ explanation is that tree planting prior to the 1995-99 surveys may have taken place in some Curlew breeding areas, that the trees were still becoming established and that the Curlews still present.  Whether these birds were successfully raising chicks we shall never know.

RC burnt moorland

Moorland managed for Grouse shooting

Another anomaly in this first period was that Curlew density was highest in areas with high crow abundance. This may look odd until you also consider the strong association between Curlew numbers and numbers of Red Grouse and Pheasant. Provide the right conditions for these ground-nesting species to flourish and you’re likely to draw in predators.

The bigger picture

Fortunately, and thanks to the volunteers who collect Breeding Bird Survey data every year, the researchers were not constrained to one time period. They could also look at 2007-11 and changes in Curlew distribution in the intervening period. Anyone interested in the finer detail will want to read the whole paper but here are my take-home messages.

Habitat associations

  • GT nest in uncut juncus

    Nesting in rushes

    Semi-natural grassland supports the highest densities of breeding Curlew, of any habitat.

  • Enclosed farmland, particularly when fields contain arable crops, has far fewer Curlews, supporting the theory that the ‘improvement’ of semi-natural habitats is bad news for the species.
  • While ‘improved’ grassland was positively associated with curlew abundance in 1995–99, the more recent results suggest these habitats have declined in importance. Perhaps Curlews have withdrawn from these nutrient-rich, structure-less habitats as numbers have declined?
  • While upland heath and, to a lesser extent, bog habitats are important breeding habitats for British Curlew, they appear to have become less important through time. 

Game management and predation

  • GT predated

    Predated nest

    High Curlew densities were associated with areas with more Red Grouse and Pheasant, despite management for Red Grouse and Pheasant occurring in largely different habitats.

  • Curlew population declines were greatest in areas with high crow abundance and numbers of Curlews were lower in areas with more foxes. “Our findings support the hypothesis that measures to reduce predation pressure from generalist predators such as foxes and crows are likely to be very important for Curlew”.
  • While Red Grouse abundance was positively associated with Curlew abundance in both time periods, rotational strip burning was negatively associated with Curlew abundance in 2007–11, though weakly so. The authors suggest “while low levels of strip burning could plausibly be beneficial for Curlew, by creating variation in habitat structure, too much may be detrimental, as burning can impact peatland hydrology and consequently soil moisture, reduce invertebrate prey, or alter vegetation structure or composition”.
  • Significant areas of semi-natural habitats in Britain are protected as Sites of Special Scientific Interest, National Nature Reserves and/or Natura 2000 sites. Curlew densities are now higher where there is a greater extent of protected area coverage.

Climate change

  • Curlew abundance is lower if summer temperatures are higher.
  • Declines were greatest in areas of high winter temperature, conditions which may have negative impacts on invertebrate populations.
  • Declines were greatest in areas of low summer rainfall.

What to do for Curlews?

nest in short vegetation

Nowhere to hide – Curlew nesting in cut rush

We cannot do much about climate impacts in the short term, and site protection is unlikely to reverse the national declines. The key things to focus on, according to the authors of this new paper, are “habitat restoration and reducing the negative impacts of predators”. Even if the details of the treatment plan have not been worked out, there appears to be a general diagnosis – there is not enough habitat of sufficient quality for Curlews to raise their chicks. While predator impacts may not have been the original cause of population declines, there is a broad consensus that reducing predator pressure is essential for successful species recovery.

So, we’ve noticed a decline, there is a diagnosis of the problem and there is a broadly accepted treatment plan of creating better habitat and reducing predator pressures. The next phase is to monitor what works, which is where national collaboration comes in. Curlews are not only found on nature reserves; they are ‘out there’ in land owned and managed by all sorts of people with a broad range of motivations, including farmers, shooting estates, statutory agencies and conservation charities. Single land-owners and local groups are working in partnerships to try to improve breeding habitat and reduce predation. What is working – and in which circumstances?

GT ad and chickAt the end of the new paper is a key section advocating “the need for the rapid establishment of intensive studies to identify the mechanistic drivers of the patterns observed here and to test potential conservation management interventions”. Ideally, these will look at issues such as:

  • RC poolHow Curlew numbers relate to variations in how intensively land is used for agriculture, forestry and grouse moor management.
  • How predator abundance and invertebrate resources relate to Curlew abundance and importantly, reproductive success.
  • Which potential restorative conservation management interventions best improve habitat quality and reduce the impacts of generalist predators.
  • Whether there are agri-environment schemes that can improve habitat quality for Curlew more broadly in the wider countryside. This may well involve better understanding the impacts of drainage on soil invertebrates.

In the absence of sufficient funding to conduct all these experiments as proper trials, it is to be hoped that the RSPB’s Trial Management Project and a new initiative by the Game & Wildlife Conservation Trust (links below) will enable local experiences to be shared in a national framework. Further collaboration is being encouraged through the UK and Ireland Curlew Action Group and a series of workshops organised through The Curlew Forum.

Links to local and collaborative initiatives in the UK and Ireland

RSPB GWCThttps://ww2.rspb.org.uk/our-work/conservation/projects/curlew-recovery-programme

https://www.gwct.org.uk/action-for-curlew/

http://www.curlewcall.org/

https://www.npws.ie/research-projects/animal-species/birds/curlew-task-force-august-2017

This list will be updated as and when I am notified of appropriate links.

Paper

Environmental correlates of breeding abundance and population change of Eurasian curlew Numenius arquata in Britain

The paper appeared in Bird Study, published by BTO, on 31 August 2017.

The authors are Samantha E. Franks (BTO), David J. T. Douglas (RSPB), Simon Gillings (BTO) and James W. Pearce-Higgins (BTO). BTO work on this paper was funded via the Trust’s Curlew Appeal.

RC roosting


 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

 

 

A great summer for Iceland’s waders?

As July 2017 turned into August, the first juvenile Icelandic Black-tailed Godwits started to arrive in the UK – soon they were everywhere. Had this been a good year for waders and wader research in Iceland?

juvvy blackwits

Flock of juvenile Black-tailed Godwits in Devon

An increasing amount of wader research is taking place in Iceland, much of which is part of an international partnership between the South Iceland Research Centre (University of Iceland), the University of East Anglia (UK) and the University of Aveiro (Portugal). Although the main focus has been on Black-tailed Godwits, Whimbrels and Oystercatchers, there is a lot more to this collaboration.

Winter into spring

january surveyThe spring season started early for Verónica Méndez, who is studying the migratory decisions made by Iceland’s Oystercatchers. About one third of these birds stay in Iceland for the winter but most are thought to migrate to Ireland and western coasts of the UK. By looking for colour-ringed individuals in January she was pretty sure that she would be sampling resident birds. There’s a blog about this project here. At the same time, sightings of migratory birds were being reported from the UK and Ireland.

Since 2000, there have been annual spring surveys of arriving Black-tailed Godwits. Jenny Gill and I arrived on 13 April and started our survey routine of regular visits to estuaries, wetlands and stubble fields in south and west Iceland. Icelandic birdwatchers cover other sites in the east and south of Iceland. The dates of the arrivals of individual birds have already contributed to a paper about what is driving earlier spring migration of the species, which is written up in this blog.

FrenchIn cold northerlies, migration from Ireland, the UK and mainland Europe was slow in 2017. This is something we have seen before and described in this blog about the appearance of large flocks in Scotland. A record number of Black-tailed Godwits – 2270 birds in total – were seen on the Scottish island of Tiree on 25 April 2017, including a minimum of 23 colour-ringed birds. We saw one of these birds four days later, fast asleep on a hay field near the south coast of Iceland.

Breeding studies

The 2016/17 winter had been relatively warm and wet in Iceland and the ground was not frozen when waders returned from Europe. The Black-tailed Godwits did not stay for long on the estuaries before moving inland to breeding territories.

The Oystercatcher project got off to an early start. oyc crossIn collaboration with Sölvi R Vignisson, Ólafur Torfason and Guðmundur Örn Benediktsson, the team colour-ringed 177 new adults and 144 chicks in a range of sites around Iceland. This year’s adults have white rings with two letters on the left leg and two colour-rings on the right, whilst chicks have grey instead of white. A smaller number of youngsters ringed in 2016 have green rings with engraved letters and some adults from previous years have green flags.

As part of a study to try to understand the migratory behaviour of young Oystercatchers, José Alves & Verónica Méndez have fitted GPS/GSM transmitters to a small number of big chicks. Which birds will migrate and what determines the strategy? Two birds have already made what appear to be exploratory trips around southwest Iceland, before returning to their natal sites.

FIRST2OYCSAt the time of writing (26 August), none of the birds with trackers has yet left Iceland but the first two colour-ringed birds have been seen in Ireland – an adult from the east and a juvenile from the south (see map).

Breeding studies of Black-tailed Godwits have been ongoing since 2001 and a small number of adults and chicks were ringed this year. This graph, which appears in the blog Why is spring migration getting earlier? showed that recent recruits to the population arrive in Iceland earlier than birds from previous generations.

timing hatching

Dates of spring arrival into Iceland of 46 individuals hatched in different years and subsequently recorded on spring arrival (reproduced from Gill et al. 2014)

Pressures on Iceland’s waders

tableIceland is hugely important for breeding waders. It holds about 75% of Europe’s breeding Whimbrel, over half of the region’s Dunlin and perhaps half of its Golden Plover. Although changes to the way land is farmed may have provided opportunities for some species, such as Black-tailed Godwits, intensification and the timing of operations have the potential to impact distribution and breeding success. A paper by Lilja Jóhannesdóttir was written up as a blog Do Iceland’s farmers care about wader conservation? and she successfully completed her PhD Links between agricultural management and wader populations in sub-arctic landscapes in June 2017.

T with BTGThe amount of woodland is changing in Iceland, with more forestry and shelter belts around summer cottages. This is an issue that was highlighted in an AEWA report published in the autumn of 2016. In the spring, Aldís Pálsdóttir started a new PhD at the University of Iceland, in which she will explore the effects of forestry on breeding waders in Iceland. Her first task in the field was to measure the effects of forest patches on breeding wader distribution, which involved walking over 400km of survey transects! Complementary work this summer by Harry Ewing, as part of his Masters in Applied Ecology and Conservation at the University of East Anglia, has explored how levels of wader nest predation vary with distance from forest patches. There’s more about the effects of woodland on breeding waders in this recent Lapwing blog: Mastering Lapwing Conservation.

Deploying and collecting geolocators to study migration

Geolocators provide a cost-effective way of collecting information on the year-round movements of individual birds, as long as birds can be recaught in the breeding season following the deployment of the tags. This blog summarises a useful paper about the safe use of geolocators.

whimbrelCamilo Carneiro is studying for a PhD at the University of Aveiro. His project, entitled Bridging from arctic to the tropics: implications of long distance migration to individual fitness, takes him to Iceland in the summer and to Mauritania and Guinea-Bissau in the winter time. By putting geolocators on Whimbrels in Iceland, he can establish the migration strategies of individuals. He has already mapped 96 migrations of 32 individual birds and we look forward to seeing the results from his studies. A flavour can be found here, in blogs about the migration of Icelandic Whimbrel and the first results of initial geolocator work by José Alves, one of Camilo’s supervisors.

RingoRinged Plovers that breed in Iceland are thought to spend the winter in southern Europe and northern Africa. Böðvar Þórisson has been studying breeding Ringed Plovers for many years, with recent work including using geolocators to explore the migration routes and timings of individuals. This year he managed to retrieve 7 of the 9 geolocators that he put on in 2016 – look out for a poster on this at IWSG 2017 in Prague. These birds had spent their winters in Mauritania, Portugal, Spain, France and southern England. 16 new tags were deployed during 2017, including a number on the same birds as in 2016.

RNPIn collaboration with Yann Kolbeinsson and Rob van Bemmelen, Jóse Alves and other members of the team have been using geolocators to study Red-necked Phalarope migration. Some birds migrate to the Pacific Ocean around coastal South America and the Galapagos but how do they get there and what is the timing of their movements? These two articles tell the story of one bird from Shetland (UK) and moulting flocks in the Bay of Fundy (Canada). Sixteen new geolocators were deployed but none of the ten deployed in 2016 were retrieved. Perhaps Red-necked Phalaropes are not that site-faithful?

So how good a breeding season was it?

2017 chick surveyAs described in this blog, the productivity of Iceland’s Black-tailed Godwits is closely linked to May temperatures – unless a volcano erupts. Each June, Tómas Gunnarsson collects information on the number of successful broods, based on a 198 km car-based transect through south Iceland. Repeating this survey in 2017 he discovered a record number of broods, adding the right-hand orange dot to the graph alongside. May 2017 was warmer than any spring during the study period covered for the IBIS paper and the number of June broods was higher too. It is not surprising that there are so many reports of juvenile Icelandic Black-tailed Godwits in Britain and Ireland this August.

For other species, where productivity is recorded in the same manner (Whimbrels, Oystercatchers and Golden Plovers), the 2017 season was also the best in the period since 2012. Perhaps other species, such as Redshank and Snipe, did well too? Will these cohorts of juveniles be big enough for there to be a detectable uplift in number on this winter’s I-WeBS and  WeBS counts?

sunset


 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

 

 

 

Special Black-tailed Godwits

What will happen to 25 head-started juvenile Black-tailed Godwits that were released at Welney, Norfolk, yesterday (12 June)? Here’s how birdwatchers can help to provide answers.

blog header

Black-tailed Godwits nest in the grazing marshes of the Nene Washes in the UK. Photographs in blog from Mark Whiffin, Jennifer Smart, Ian Dillon, Verónica Méndez & Haije Valkema.

If you have heard anything about Project Godwit, you’ll know that eggs from seven pairs of Black-tailed Godwits nesting in the RSPB’s Nene Washes reserve in Eastern England have been hatched in incubators and reared in captivity at WWT Welney. By head-starting’ these eggs/chicks, it is hoped that the tiny, Fenland Black-tailed Godwit population, estimated at around 40 pairs, can receive a much-needed boost in numbers. These birds belong to the limosa subspecies. In the winter, the Washes are home to thousands of islandica Black-tailed Godwits. There’s a blog about the two subspecies here.

blog release pen

Time to stretch their wings

On 12 June, 25 head-started godwits were released from their aviary. What will happen now? The Project Godwit Team from RSPB and WWT is appealing to birdwatchers to look out for these special birds as they leave the Washes. They are expected to spend time around the East Anglian coast before heading for Spain, Portugal and African countries such as Senegal and Gambia. The chicks have been individually marked but each member of the group has a green ring above a lime ring (engraved with a letter E) on the right tibia (top part of the leg), as can be seen in these pictures.

Blog GY-GE

GY-GE (green yellow – green E)

Sightings can be reported to the Project Godwit Team https://projectgodwit.org.uk/get-involved/report-a-sighting/ or to jennifer.smart@rspb.org.uk

Background

The small number of Black-tailed Godwits that breed in East Anglia’s wet grassland belong to the limosa subspecies. There are far more birds of this subspecies on the other side of the North Sea but nowhere near as many as there were just a few years ago. (Read this blog about the 75% decline in numbers in The Netherlands).

blog soggy nest.jpg

Innundation can be a problem in the Washes, which are designed to store flood-water

Unsurprisingly, the tiny breeding population in the UK, individuals of which follow the same migration route as those in The Netherlands, is also under threat. By taking a few first clutches of eggs, and hatching and rearing chicks away from the dangers of predators and flooding, it is hoped that numbers can be given a boost. Most of the pairs from which eggs were taken have laid replacement clutches – giving them a chance to raise a second family themselves.

If a significant number of godwit chicks return to breed then that will be excellent but that’s looking a long way ahead. For now, the Project Godwit team want to know if the released juveniles are going to behave in the same way as they would have done had they been reared by their parents. That’s where birdwatchers come in. As these special birds learn to fly and then disperse from their Welney release site where will they go?

Head-starting

revised mapRSPB scientists colour-ringed free-living Black-tailed Godwits between 1999 and 2003 and more have been marked over the last 3 years. The map alongside indicates sites in East Anglia where previous generations of chicks and adults have been seen in the months from June to September. You’ll see that a lot of them have been spotted on the North Norfolk coast and others in Suffolk – which are also places where there are a lot of birdwatchers. Young godwits – like most other waders – are deserted by their parents before they themselves are ready to make their first migratory journeys. When it is time to move, they rely on an in-built sense of direction but they could also perhaps follow the lead of adults that are not their parents. The hope is that the head-started chicks will behave in a similar way to their naturally-reared brothers and sisters but the Project Godwit team will only know what happens when birdwatchers send in their sightings. It’s an exciting and anxious time for Hannah Ward, the project leader, and her RSPB and WWT colleagues.

What happened? There’s an update about where the chicks were seen in this blog from Project Godwit

Where to next?

Birdwatchers in Norfolk and Suffolk probably have the biggest chance of finding these colour-ringed birds but some of the young Black-tailed Godwits may be seen further south, in Essex and Kent, before crossing the English Channel. During autumn, godwits from this population start to be seen around the Iberian coast, with sightings from between the Tagus Estuary (Lisbon) and Alicante in southern Spain.

blog RLGE
RL-GE (red lime – green E)

The Limosa Black-tailed Godwits (the subspecies that breed in East Anglia, The Netherlands and surrounding countries in mainland Europe) spend the mid-winter period either in Africa or Iberia (Spain and Portugal). As numbers have declined, so the proportion of birds wintering in Europe has become more significant. Some of the newly ringed chicks – which all have a green ring with lime E scheme marker on the right leg – may venture as far as countries on the other side of the Sahara but others could stay in Iberia. Dutch researchers will be visiting African wintering areas to catch up with their limosa birds from the Netherlands and have found Nene Washes birds in previous years. If they get a photograph of one of the head-started birds that will be a day of huge celebration for the Project Godwit team. A sighting in Spain or Portugal will be equally encouraging – anyone planning a birdwatching break in Cota Doñana or the Algarve this winter?

The return journey

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Spring godwit flock takes off from a Portuguese rice field

In the late winter and early spring, the more adventurous Black-tailed Godwits that flew as far as west Africa will cross the Sahara and head for Spain and Portugal. Here, vast flocks gather in places such as the rice fields of the Tagus Estuary. Roos Kentie has been studying these birds; there are two WaderTales blogs about her work that may well be relevant to the head-started birds from the Fens.

There has been a 75% decline in the Dutch population:

headerOn average, godwits that fly all the way to Africa nest earlier than those that short-stop in Iberia:

Hang out the bunting – time to party!

If the Project Godwit team is very lucky, the first of this year’s young Black-tailed Godwits will return to the Ouse and Nene Washes in April or May in 2018. At this time of year, flocks of 1000 or more Black-tailed Godwits are already feeding on the flooded washes but these are birds of another subspecies – islandica godwits that are moulting and putting on fat for their return journeys to Iceland. By the middle of May these islandica flocks will have moved north and the limosa birds should be breeding. There’s a blog about the two subspecies here.

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There’s a worm in here somewhere – will one of these godwits return next year?

Roos Kentie has shown that some Dutch godwits nest in their first year. Imagine how exciting it will be if one of this year’s head-started bird is found breeding in the Nene or Ouse Washes next year. Time to ice the cake and have a party!

You can follow the fortunes of these pioneering Black-tailed Godwits on Twitter via @projectgodwit

Funding

Project Godwit is a partnership between RSPB and WWT, with major funding from the EU Life Nature Programme, The HSBC 150th Anniversary Fund, Natural England and the Heritage Lottery Fund.


 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

 

Mastering Lapwing conservation

Predation and perceived risk of predation in Lapwings

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Students from the University of East Anglia and conservation organisations such as the RSPB Centre for Conservation Science benefit greatly from applied conservation research by MSc students. Two recent papers, reporting on projects by Sam Leigh and Nik Bertholdt, focus on risks and perceived risks to nesting Lapwings.

Lapwings – a diminishing asset

Blog adultLowland, breeding waders are increasingly confined to nature reserves, and the wet grasslands of the Norfolk Broads retain some of the largest remaining populations of Lapwing and Redshank in England. Over the last two decades, a collaboration between Dr Jennifer Smart of RSPB and Professor Jennifer Gill the University of East Anglia (UEA) has helped to identify some of the key habitat management options that can attract breeding waders. A series of dissertation projects by nine students on the Masters in Applied Ecology and Conservation course at UEA have contributed greatly to this knowledge, complementing four PhD and three post-doctoral projects, as described in Jen Smart’s Wader Study perspectives paper.

Blog chickIn a previous WaderTales blog – A helping hand for Lapwings – there is a summary of some of the actions that can support breeding populations. Short, grazed grass and surface water are attractive to waders at the start of the breeding season and invertebrate densities are greater around these wet features, which generally dry out as the season progresses. However, unsustainably high levels of nest predation mean that numbers of breeding waders are struggling to recover, despite the creation of great breeding habitat. We need to understand which landscape features might influence the risk of nest predation, especially if these features might be managed in ways that could reduce predation rates.

Two  recent MSc dissertations by Sam Leigh and Nik Bertholdt have focused on different aspects of predation risk. Both have recently been published, in Animal Conservation and Bird Study.

Sam LeighBlog Sam

Sam Leigh asked whether patterns of nest predation on a major RSPB nature reserve (Berney Marshes, in the Norfolk Broads) were influenced by management of the surrounding area. Much of the land adjacent to Berney is managed as arable farmland, whilst other areas are grassland. Some of the latter fields are within agri-environment schemes (AES) for breeding waders, and are therefore managed more sympathetically than the commercial land. The main nest predators of Lapwings are foxes, and their activity around the reserve might vary depending on surrounding land (given the large areas over which they can roam).

Blog foxSam compared nest survival rates within the reserve at different distances from the reserve edge, in areas with different surrounding land. He found that foxes tend to avoid parts of the nature reserve next to commercial farmland that is not being managed to favour breeding waders. In parts of the nature reserve that are adjacent to AES-managed land, fox activity was higher and nest predation rates remained constant with increasing distance from the reserve edge into the reserve. This lack of an ‘edge effect’ would suggest that foxes do not distinguish between fields within the nature reserves and AES land managed outside the reserve when they are searching for wader eggs.

Impacts of grassland management on wader nest predation rates in adjacent nature reserves. Leigh, S.J., Smart, J. & Gill, J.A. (2016) Animal Conservation DOI: 10.1111/acv.12283

Nik BertholdtBlog Nik

Nik Bertholdt worked at Stanny Farm in Suffolk, a commercially-farmed site with breeding waders nesting on the wet grasslands. He had help from extremely supportive landowners, Paul & Louise Cooke, who provided Nik with somewhere to stay and a grant to help with research costs, and local wader enthusiasts (led by Rodney West). Nik wanted to know if the presence of trees and small copses within wet grasslands could potentially influence patterns of Lapwing nest predation. Predators such as foxes and corvids could be attracted to these areas by the presence of small mammal prey (within and around the woodland), the availability of perches for birds or den sites for mammals.

Blog Hay picNik found that Lapwings avoided nesting close to (within 500 m of) the copses but that nest predation rates did not vary with distance from copses at greater distances. This could either mean that predator activity is not focused on these copses or that the Lapwings have avoided predation risk by nesting further away – and hence outside the area of influence of predators. Whatever the reason, Lapwings are not using what would otherwise be thought of as suitable nesting habitat, thereby potentially reducing the numbers of pairs that could nest in the area. Removal of small woodlands in grasslands in which breeding waders are a conservation priority could increase habitat availability for Lapwings.

Landscape effects on nest site selection and nest success of Lapwing Vanellus vanellus in lowland wet grasslands. Bertholdt, N. P., Gill, J.A., Laidlaw, R.A. & Smart, J. (2016). Bird Study DOI:10.1080/00063657.2016.1262816.

UEA MSc in Applied Ecology & Conservation

logoBy working alongside conservation organisations throughout the world, students on the Masters in Applied Ecology and Conservation course at the University of East Anglia have been well placed to combine research experience with learning that is directly aimed at furthering a career in ecology. Sam Leigh is now undertaking a PhD at the University of Reading on ecosystems services in agricultural systems and Nik Bertholdt works for Natural England. On average, three projects each year are later written up as peer-reviewed publications, with support from project supervisors at UEA and in partner organisations, resulting in a WIN-WIN-WIN situation for the students, the university and the partner organisations.

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Harry is using dummy nests, containing hens’ eggs to study predation associated with proximity to Icelandic woodlands.

Students on the MSc AEC course at UEA travel all over the world to carry out conservation-related research projects. For example, Harry Ewing (pictured here) is in Iceland, studying the effects of woodland patches on breeding waders. Other MSc students from this group are currently working on a wide range of projects, including warblers in East Anglia, invasive caterpillars in the Seychelles, sloth bears in India, critically endangered turtles in Vietnam and tropical forest restoration in Brazil.

To learn more about the UEA AEC course please read page 16 of this brochure. Download here. 


 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

 

 

 

 

 

 

Should Black-tailed Godwits cross the Sahara?

Are Dutch-breeding limosa Black-tailed Godwits that now winter in Spain and Portugal doing better than ones that travel to the other side of the Sahara?

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Changing weather patterns and land management are providing opportunities for many bird species to modify their migration patterns – both in terms of space and time. Dutch limosa Black-tailed Godwits were traditionally thought of as long-distance migrants that spent the winter months in countries such as Senegal and Guinea Bissau. In recent years, however, increasing numbers have been observed to fly no further south than Spain and Portugal, where their winter distribution overlaps with the islandica race.

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Fewer Black-tailed Godwits  return to The Netherlands each spring

As has been described in a previous blog (Dutch Black-tailed Godwits numbers down by nearly 75%), the limosa population in western Europe is in serious decline. The proportional change is therefore even more impressive than the change in numbers. Márquez-Ferrando et al showed that the number of birds wintering in the Doñana Wetlands, Spain has increased from 4% of the flyway population in the late 1980s to 23% in 2011.

The annual distances travelled by African-wintering and Iberian-wintering Black-tailed Godwits are hugely different, being about 10,000 km and 4,000 km, respectively. A Doñana bird therefore needs to find much less fuel for migration when compared to  a bird in Guinea-Bissau.

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Flamingos for company in Spain

Logic might suggest that travelling less far should have benefits. Provided that an Iberian bird survives the winter, it should be better placed at the start of the next breeding season? There’s less far to travel to return home and it might be easier to use weather cues in Spain & Portugal to determine the best time to make the journey, given that Atlantic lows affect the weather patterns across large sections of western Europe?

In a paper in Ecology & Evolution, Rosemarie Kentie and her colleagues investigate whether there are differences in timing of breeding and breeding success between Black-tailed Godwits that spend the winter in Africa and those that only travel as far as Iberia. Do European wintering birds start breeding earlier, do they choose the best breeding territories and do they have a higher chance of successfully raising chicks?

Timing of arrival

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Maroune, Khady Gueye, Jos Hooijmeijer, Haije Valkema & Idrissa Ndiaye in Guinea Bissau

This paper benefits hugely from colour-ring sightings made in both African and European wintering areas. Most of these have been collected by dedicated teams but additional reports by other birdwatchers are also gratefully acknowledged. Their efforts distil into 180 known Iberian-winterers and 131 known African-winters.

When the spring arrival dates of males and females of the two groups were compared, Rosemarie Kentie discovered that African winterers arrive back two days earlier than Iberian winterers and that males return to the breeding grounds three days earlier than females (see table). Mean lay date of first egg was five days earlier for African birds.

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Mean spring arrival dates

Although the magnitude of the differences seem quite small, the results are statistically significant and previous work has shown strong effects of timing of breeding on reproductive success. What is clear is that birds that only have 2,000 km to travel are no earlier (and  on average are actually later) than birds that travel 5,000 km. Both groups spend several weeks together in Iberian rice fields, before heading north, but a difference based on wintering location is still detectable.

mapInterestingly, this pattern of timing is similar to that previously found by José Alves and colleagues for islandica Black-tailed Godwits. In islandica, there is a much smaller wintering range, from Iberia in the south to Scotland in the north. Despite the longer journey back to Iceland from Portugal, these southern birds tend to reach Iceland about five days earlier than birds wintering in England. The energetic constraints of birds wintering in (and migrating from) different parts of the range are discussed in the paper Overtaking on migration: does longer distance migration always incur a penalty? or you can read this WaderTales blog: Overtaking on Migration.

Breeding success

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Rocio Marquez-Ferrando rings an adult Black-tailed Godwit on the Dutch breeding grounds

In the limosa paper, the authors look for different measures of breeding success for Iberian and African winterers. There seems to be no link between wintering area and the quality of the territory in which birds breed, although the earlier birds may have had earlier access to better territories (see paper for details). There’s no difference in size between birds in the two groups and the daily nest survival rates were not different either. The only potential benefit for either group is that Iberian-wintering females lay slightly bigger eggs. Given that other wader studies have shown that bigger eggs turn into bigger chicks and bigger chicks are more likely to fledge, there may be a breeding advantage for birds travelling less far. This is a statistically different result (i.e. there is a measurable difference) but the magnitude is only 3% difference in egg weight, and the authors question whether this can really be significant, biologically. Is this extra mass enough to make a practical difference to the probability that these bigger eggs will turn into more, bigger or fitter youngsters?

Why are godwits now wintering in Iberia?

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Fewer and fewer Black-tailed Godwits are crossing the Sahara to countries such as Guinea Bissau

We know that individual Black-tailed Godwits, like most other waders, use the same wintering areas each year. Having once settled into a particular pattern – African or Iberian – then that’s almost certainly the pattern for life. As recently as the 1980s, 96% of the western population of limosa were flying 5,000 km each autumn. The fact that few birds used the 2,000 km option then and that an increasing number do so now may suggest that winter conditions in Iberia have become more suitable for Black-tailed Godwits. This may be a good thing because there’s a line in the paper that makes for interesting reading “the mortality rate of godwits equipped with satellite tags was highest during the crossing of the Sahara Desert”.  Perhaps it’s harder to find the resources for the journey north from countries such as Guinea Bissau? That’s going to be the subject of a future paper. Meanwhile, there’s more about the satellite-tagging project on the King of the Meadows website.

Read the full paper

RoosDoes wintering north or south of the Sahara correlate with timing and breeding performance in Black-Tailed Godwits?

Rosemarie Kentie, Rocío Marquez-Ferrando, Jordi Figuerola, Laura Gangoso, Jos C.E.W. Hooijmeijer, A. H. Jelle Loonstra, Frédéric Robin, Mathieu Sarasa, Nathan Senner, Haije Valkema, Mo A. Verhoeven and Theunis Piersma


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

Flyway from Ireland to Iceland

There are over forty WaderTales blogs so far. Here’s a selection that may appeal to birdwatchers in Ireland.

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The Ireland to Iceland air link opens in February and does not close until well into May, as swans, geese, ducks, waders, gulls and passerines head north. At the end of June it opens again, with the first failed breeders returning to Ireland. Species such as Oystercatcher and Black-tailed Godwit spend much more of the year in Ireland than they do in Iceland.

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Most Oystercatchers are being ringed with two letter engraved rings, along with two colour-rings: Photo Tómas Gunnarsson

The island of Ireland holds important populations of waders in the wintertime – everything from Grey Plovers from Siberia to Turnstones from Canada – but there is  special relationship with Iceland. It’s the next stopping off point for passage Sanderling, as they fly from Africa to Greenland, and the ultimate destination for lots of wintering birds such as Redshank and Golden Plovers.

Oystercatchers lead the way

A lot of the Oystercatchers seen around Ireland’s coastline breed in Iceland, as has been shown by the Dublin Bay Birds Project. Birds start moving north very early, as shown by the appearance of four yellow-ringed Dublin Bay birds in Tiree before the end of February this year. Migratory decisions for Icelandic Oystercatchers explains how a new Icelandic project is examining the costs and benefits of being a migrant. Irish reports of Icelandic colour-ringed birds are helping to provide answers – and the Dublin Bay birds are providing great additional data.

snipe-1Each autumn, Irish-breeding Snipe are joined by much larger numbers from the north and east. About a quarter of foreign-ringed snipe that have been found in the island of Ireland are of Icelandic origin, compared to just one out of 255 in England. Snipe & Jack Snipe in the UK and Ireland compares the migratory strategies of the two species and laments the decline of Common Snipe, as a breeding species.

whimbrel-mig-fig1Some of the last waders to use the Ireland to Iceland flyway are Whimbrels, many of which stop off in Ireland on spring migration. Whimbrels on the move summarises a paper about the movements of Icelandic, ringed Whimbrel. Since its publication, a new paper has shown that Whimbrel are able to fly between Iceland and west Africa in one jump but that they sometimes need to stop off on the way north. See Very rapid long-distance sea crossing by a migratory bird by José Alves and colleagues.

Black tailed-Godwits

WaderTales was invented as a way of providing feedback to colour-ring readers who focused on Black-tailed Godwits. There are 10 blogs about the species, some of which may well appeal to birdwatchers who have spotted colour-ringed birds anywhere between Belfast Harbour and the Shannon Estuary.

pairs-mapWe are all aware that migration is getting earlier but how does this happen? Monitoring the annual arrival of individual colour-ringed Black-tailed Godwits in Iceland may well have provided an answer. Why is spring migration getting earlier? reveals that it is new recruits into the breeding population that are setting the pace; they are reaching Iceland earlier than previous generations.

Another fascinating story that is revealed by colour-ringing is the synchronous arrival of the two members of breeding pairs of Black-tailed Godwits, even if one wintered in Ireland and the other in France. You can read more here.

Breeding Waders

WaderTales were developed in East Anglia so many of the articles about breeding waders have an English feel to them. Hopefully, some of the blogs will still appeal. Anyone trying to support breeding Lapwing populations might be interested in A helping hand for Lapwings, which also talks about Redshanks.

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There’s an Icelandic focus too and a new blog, which looks at the attitudes of farmers, will resonate with conservationists (scientists, birdwatchers and farmers) who are trying to work together to improve conditions for Irish breeding waders. As Icelandic farming expands, what are farmers prepared to do to support breeding waders, many of which are destined to spend the winter on Irish estuaries. See: Do Iceland’s farmers care about wader conservation?

Ireland – a special place for Curlews

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Curlews fly vast distances to spend the winter on the estuaries of Britain & Ireland (© Graham Catley)

Is the Curlew really near-threatened? considers the plight of breeding Curlew. It’s easy to understand why BirdWatch Ireland, RSPB, BTO and GWCT  are focusing on this species How long will it be until breeding Curlew are lost from Ireland, completely?

The threat to the Curlew is real, especially when set in an international context. Two species of curlew are probably already extinct and other members of the Numeniini (curlews, godwits and Upland Sandpiper) are facing a similar set of problems to those that probably caused the demise of the Eskimo Curlew and Slender-billed Curlew. Why are we losing our large waders? outlines the background to a global problem.

There’s a WaderTales blog that summarises a new paper from BTO and RSPB – Curlews can’t wait for a treatment plan. Although the analyses are based on British data, the results are highly relevant to Irish Curlews.

Conservation issues

Hundreds of  birdwatchers take part in the Irish Wetland Bird Survey (Republic) and the Wetland Bird Survey (Northern Ireland). These counts identify and monitor key sites for wintering waders – and wildfowl. Whilst mud  and sand-flats are, of course, important to waders, so are roost sites. A place to roost discusses the importance of safe, high-tide roosts, especially in terms of energetics. It has been estimated that the cost of flying to and from roosts might account for up to 14% of a bird’s daily energy expenditure. That’s something to think about next time you see a dog chasing off a flock of roosting waders.

Further reading

b-stubble-godwitsHopefully, this summary  gives a flavour of some of the issues being faced by Irish waders and the research to which they are contributing. There are already over 40 blogs in the WaderTales series, with one or two new blogs being produced each month. If you want to know how volcanoes affect breeding waders in Iceland, why Black-tailed Godwits wear colour-rings or if there are costs to carrying a geolocator have a look here.

And finally …

There’s a useful summary about wader migration to, from and through Ireland in Which wader, when and why?

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.

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?

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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.

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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. 

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.

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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

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Black-tailed Godwit pairs – the importance of synchrony

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

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

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

A tale of two godwits

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How long should this godwit wait for its mate?

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

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

2004: Come the spring of 2004, RO-RO and RY-RO arrived at the same time and got back together.

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

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

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

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

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Each line joins the wintering locations of a pair of godwits

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

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

Warmer springs

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

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

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

Potential benefits of re-pairing with the same mate

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

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Nests are well hidden

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

The complexities of incubating eggs

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

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

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This actogram from the Bulla Nature paper creates some wonderful patterns

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

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

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Incubating Ringed Plovers change places frequently

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

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

What does this mean for RY-RO and RO-RO?

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


GFA in Iceland

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

@grahamfappleton

Dutch Black-tailed Godwit numbers down by nearly 75%

Colour-rings and radio-tracking are helping to chart the ongoing decline of the Dutch Black-tailed Godwit population.

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A Portuguese rice field, full of limosa Black-tailed Godwits; most are Dutch breeders

The Black-tailed Godwit is the national bird of the Netherlands, the country in which the vast majority of the West European limosa race breed. These Dutch birds are an important part of the country’s cultural heritage and are of major international significance. Large amounts of money have gone into supporting the species, and the meadows that they share with others such as Redshank and Snipe, but efforts so far have failed to reverse a Black-tailed Godwit decline that has been going on since at least the 1970s. This negative situation is in stark contrast to the increases seen in the islandica subspecies that breeds in Iceland and winters in countries between Scotland and Spain. (There’s a comparison of the two subspecies in this WaderTales blog)

Counting Black-tailed Godwits

vero-pretty-flockIt is often easier to measure changes in numbers of waders on the wintering grounds, when birds are in flocks, than when pairs are thinly spread across their breeding ranges. For Dutch Black-tailed Godwits, most of which spend the winter in African countries, south and west of the Sahara, however, the best opportunity to monitor population trends occurs in Spain and Portugal in February, when the birds are on their way back to breed.

Each year a small group of ornithologists visit key sites in Extremadura, the Doñana Wetlands and the rice fields of the Tagus Estuary, to count flocks of birds and to look for colour-ringed birds. They’re able to use these counts and sightings of colour-ringed birds to assess what has happened to numbers in the previous twelve months.

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grutto met ringen (ringed Black-tailed Godwit)

In three of the years since 2007 they’ve witnessed increases but in most years the numbers have gone down. As February 2017 approaches, what will this year’s score be? How many of last year’s birds will have died and how many chicks hatched in 2015 and 2016 will be making the migratory journey north for the first time?

When assessing how many breeding godwits there are in the Netherlands the researchers collect and use the following information:

  • Counts of birds seen in flocks in Spain and Portugal.
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    It’s not always easy to see the colour-rings in rice fields

    Counts of colour-ringed birds. There’s a great one-line comment in the newly-published paper that forms the basis of this blog: ‘In total, we checked 420,206 godwits for colour-rings at Spanish and Portuguese staging sites’. That’s a lot of legs – and a huge effort.

  • An assessment of the proportion of islandica Black-tailed godwits in the flocks, so that they can be removed from the estimation process. This proportion had been established previously but were also monitored using sightings of colour-ringed birds of the islandica and limosa subspecies, and by taking account of the proportion of each population that wears rings.
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    Rosemarie Kentie in the rice fields of the Tagus estuary (Portugal)

    An estimate of the number of the birds that will be flying north to the Netherlands, as opposed to other countries. Limosa Black-tailed Godwits that pass through Iberia are on their way to a range of countries, stretching from the tiny population that breed in the UK, in the Ouse and Nene Washes, across to Germany in the east. This proportion was calculated by monitoring the movements of satellite-tagged individuals.

The results have just been published in a new paper, which also presents annual survival rates, obtained using colour-ring sightings. There is a full explanation of the methodology in the paper. You can also see maps from the satellite-tagging project on the King of the Meadows website.

postEstimating the size of the Dutch breeding population of Continental Black-tailed Godwits from 2007–2015 using resighting data from spring staging sites. Ardea 114: 213–225. doi:10.5253/arde.v104i3.a7

The authors are Rosemarie Kentie, Nathan R. Senner, Jos C.E.W. Hooijmeijer, Rocío Márquez-Ferrando, Jordi Figuerola, José A. Masero, Mo A. Verhoeven & Theunis Piersma.

Latest findings

Over the eight years of the survey work, the average decline in numbers of limosa Black-tailed Godwits has been 3.7% per year. Numbers appeared to go up between 2009 and 2011, when the calculated survival rate of young birds was high, but the magnitude of this perceived recovery may have been artificially elevated by an increase in the number of Icelandic birds. From WeBS counts in the United Kingdom, the number of islandica birds is continuing to rise.

Since 2011, the estimated annual decrease has been 6.3% per year. Such large declines can only occur if there is both low recruitment and reduced adult survival.

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Agricultural intensification has seriously affected Dutch Black-tailed Godwits

The estimated breeding population in the Netherlands in 2015 was 33,000 pairs, representing a drop of nearly 75% since 1967. However, the agricultural grasslands of the Netherlands are still the single most important stronghold for breeding limosa  Black-tailed Godwits using the East Atlantic flyway.

The authors finish with a sad conclusion. “Although enormous amounts of money and effort have been expended to conserve continental godwits, our findings make clear that these have been ineffective or insufficient.”

One wonders how much worse the situation would have been without Dutch and European support for Meadow Birds and the ‘King of the Meadows’ in particular?


take-off

Estimating the size of the Dutch breeding population of Continental Black-tailed Godwits from 2007–2015 using resighting data from spring staging sites.  

The authors are Rosemarie Kentie, Nathan R. Senner, Jos C.E.W. Hooijmeijer, Rocío Márquez-Ferrando, Jordi Figuerola, José A. Masero, Mo A. Verhoeven & Theunis Piersma.


 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