The UK hosts almost 5 million waterbirds and supports a large number of internationally important wetlands within the African-Eurasian flyway. The BTO is increasingly taking a flyway approach to its research and is applying the expertise it has gained from waterbird studies in the UK to this and other flyways. We collaborate with a wide range of government and non-government organisations and stakeholders abroad and are part of a wide diversity of projects. These range from developing new methodologies such as developing new statistical methods to estimate the number of individuals passing through a site or orgnaising international surveys, to investigating the impacts of factors such as introduced species, development and fishing on waterbirds as well as species recovery plans and designing new wetlands to mitigate the effects of habitat loss.

Red Knots and other shorebirds in Delaware Bay

In spring, Delaware Bay in the north-eastern US hosts one of the most amazing wildlife spectaculars in the animal kingdom. Millions of Horseshoe Crabs come ashore from April to July and lay eggs in the sandy beaches, which become awash with eggs. In May and early June hundreds of thousands of migrating shorebirds take advantage of this food resource and stopover to fatten rapidly so they can continue on their final leg of their long journey to their Arctic breeding areas.

BTO has been involved in the project since 1997 and this is a truly international collaboration. Working closely with Delaware and New Jersey’s Division of the Fish & Wildlife, and the Delaware Coastal Programs, BTO along with researchers from Argentina, Chile, Brazil, Canada, the Netherlands and other countries have been working to establish the causes behind alarming declines in the Nearctic sub-species of Red Knot Calidris canutus rufa and other shorebirds and also better understand how commercial harvest of Horseshoe Crabs impact the ability of migrating shorebirds to fatten.

BTO has developed ways of using stable isotopes in flight feathers to identify birds from wintering areas in Tierra del Fuego, Brazil and the south-eastern part of the USA. Each of the 1000 or so birds caught each year is individually marked and its wintering location identified. Subsequent counts, egg density surveys and resighting & foraging observations have shown that high egg densities Delaware Bay are crucial to birds’ long-term survival - underweight birds late in May are less likely to be seen in the flyway in subsequent years. Lower egg densities have been linked to declines in crab numbers due to commercial harvest for bait and the biomedical industry and also, in some years, cold weather conditions. This important long-term dataset has been used to show that this sub-species is in imminent danger of extinction unless remedial action is implemented urgently. As a result, conservation measures have been put in place to safeguard the egg resource in Delaware Bay. Publications

The number of birds “using” a site is used as a basis for designating sites important for nature conservation. To attain international importance, and thus protection as a Ramsar site, a site must ‘regularly’ support 20,000 or more waterbirds or 1% or more of the individuals of a population of a species or subspecies of waterbird. Over 138 countries have adopted these criteria and the use of the 1% criterion has been, and will continue to be, an effective tool for the identification of important wetlands for wintering waterbirds (Fuller & Langslow 1986). However, it has shortcomings, especially in the case of sites which are important for migrating birds. Birds rarely migrate all at once and the migration period may cover an extended period. Single, or multiple counts are very likely not to capture the total number of birds as some may have ‘moved on’ and some may have not yet arrived.

This project, joint with Roger Pradel & Remi Choquet from CEFE (Centre for Evolutionary and Functional Ecology in Montpellier) and Morten Frederiksen from CEH (Centre for Ecology and Hydrology, Banchory, Scotland) is developing new techniques and software to integrate count data into mark-recapture models to produce estimates of turnover and hence the total number of birds passing through a site.

Mangrove Conservation in Oman

Invited by the Oman Government and Japan International Cooperation Agency (JICA), the BTO applied its knowledge of wetland birds to help design an artificial mangrove wetland (the Qurm Nature Reserve) at Muscat in Oman. It is hoped that the creation of a series of lagoons and mangrove habitats will attract wildlife, which will in turn attract the paying visitors necessary to ensure the reserves financial self-sufficiency. Facilities will include a modern visitor and education centre over-looking the created wetlands. Publications

The European Non-Estuarine Coastal Waterbird Survey (NEWS)

The BTO took the lead on the first co-ordinated survey of waders over-wintering on Europe’s non-estuarine coasts. The survey, involving partners from 12 countries aims to provide better population estimates for birds more associated with open coastlines. Although estuaries host the most waders, non-estuarine coasts support significant proportions (>20%) of the biogeographic populations of species such as Ringed Plover Charadrius hiaticula, Sanderling Calidris alba, Purple Sandiper Calidris maritima and Turnstone Arenaria interpris. Publications

International Waterbirds Census

Together with Wetlands International, the global co-ordinator of the International Waterbirds Census and organisations from more than 100 countries worldwide, the BTO contributes to the International Waterbirds Census, by providing waterbird count data from the United Kingdom. These data are combined with data from other countries to provide information on the global state of waterbirds and to analyse trends in their population. Data for this project are stored and disseminated through the Wetlands International waterbirds database. The BTO has recently provided expertise to facilitate the design of this database. Publications

AEWA Introduced species projects

The African-Eurasian Waterbird Agreement (AEWA) covers over 116 range states in Africa, Asia, Europe and the Middle East and aims to encourage the right conditions for the conservation and management of migratory waterbirds. As the presence and continued release of introduced species is detrimental to the meeting of this aim, the BTO was asked by the UK Government to assess the scale of the problem in 1999 and to provide an update in 200. The number of introduced species in each country is highly variable ranging from zero in many countries to 72 in the United Kingdom. 16 species are thought to pose a particular threat to native waterbird species in the AEWA area. Publications

Climate change is potentially a major threat to migratory waterbirds. To help understand the issues, the AEWA secretariat asked the British Trust for Ornithology and Wetlands International to undertake a series of reports asessing the degree of threat facing waterbirds. Of 235 species of migratory waterbird occurring in Europe and Africa, all except one are experiencing some threat from climate change, and nine species face severe threats that could cause extinction. With warmer temperatures, many birds are finding their current living conditions increasingly unsuitable. Some are shifting their ranges towards cooler climates. However, species such as the Crowned Cormorant, confined to the extreme southern coast of Africa, need land to nest on and are prevented from moving poleward by the presence of the sea. A similar situation exists for those species that breed in the high Arctic, such as the Sanderling. Publications

Atkinson, P.W., Baker, A.J., Bennett, K.A., Clark, N.A., Clark, J.A., Cole, K.B., Dekinga, A., Dey, A., Gillings, S., González, P.M., Kalasz, K., Minton, C.D.T., Newton, J., Niles, L.J., Piersma, T., Robinson, R.A. & Sitters, H.P. (in press) Rates of mass gain and energy deposition in red knot on their final spring staging site is both time - and condition dependent. Journal of Animal Ecology.

Gillings, S., Atkinson, P.W., Bardsley, S.L., Clark, N.A., Love, S.E., Robinson, R.A., Stillman, R.A., & Weber, R.G. (2007). Shorebird predation of Horseshoe Crab eggs in Delaware Bay: species contrasts and availability constraints. Journal of Animal Ecology 76: 503-514.

Haramis, G.M., Link, W.A., Osenton, P.C., Carter, D.B., Weber, R.G., Clark, N.A., Teece, M.A. & Mizrahi, D.S. (2007) The value of horseshoe crab eggs to red knots: results from stable isotope, pen feeding trials, and lipid studies. Journal of Avian Biology. doi:10.1111/j.2006.0908-8857.03898.x

Atkinson, P.W., Baker, A.J., Bennett, K.A., Clark, N.A., Clark, J.A., Cole, K.B., Dey, A., Duiven, A.G., Gillings, S., González, P.M., Harrington, B.A., Kalasz, K.S., Minton, C.D.T., Newton, J., Niles, N.J., Robinson, R.A., Serrano, I. de L. & Sitters, H.P. (2006). Using stable isotope ratios to unravel shorebird migration and population mixing: a case study with the red knot Calidris canutus. In: Waterbirds abount the World, pp 535-540. Eds. G.C. Boere, C.A. Galbraith & D.A. Stroud. The Stationary Office, Edinburgh, UK. Proceedings of the Global Flyways Conference.

Atkinson, P.W., Baker, A.J., Bevan, R.M., Clark, N.A., Cole, K.B., Gonzalez, P.M., Newton, J., Niles, L.J. & Robinson, R.A. (2005) Unravelling the migration and moult strategies of a long-distance migrant using stable isotopes: Red Knot Calidris canutus movements in the Americas. Ibis 147: 738-749.

Baker, A.J., González, P.M., Piersma, T., Niles, L.J., Nasicmento, I.d.L.S., Atkinson, P.W., Clark, N.A., Minton, C.D.T., peck, M.K. & Aarts, G. (2004) rapid population decline in red knots: fitness consequences of decreased refuelling rates and late arrival in Delaware Bay. Proceedings of the Royal Society B 271: 875-882.

Mangrove Conservation in Oman

Rehfisch, M.M. & Holloway, S.J. (2005) Mangrove review in the context of Quorn Nature Reserve, Oman. British Trust for Ornithology repot to JICA

Grieve, A., Holloway, S.J., Rehfisch, M.M. & Fletcher, D.J. (2006) Qurm Environmental Information Centre (QEIC) Development Project: Creation of Natural Lagoons and Visitor Facilities. BTO Research Report No. 436, BTO, Thetford.

The European Non-Estuarine Coastal Waterbird Survey (NEWS)

Burton, N.H.K. et al. (in prep). The European Non-Estuarine Coastal Waterbird Survey. International Wader Studies 18.

International Waterbirds Census

Delany, S. & Scott, D. (2006) Waterbird Population Estimates. Fourth Edition, Wetlands International Global Series 12, Wageningen, The Netherlands.

AEWA introduced species project

Banks, A.N., Wright, L.J., Maclean, I.M.D., Hann, C., Mellan, H.J., Dereliev, S. & Rehfisch, M.M. (in press) Second Review of the Status of Introduced Non-Native Waterbird Species in the Area of the African-Eurasian Waterbird Agreement. BTO Research Report No. 487, BTO, Thetford.

Blair, M.J., McKay, H., Musgrove, A.J., & Rehfisch, M.M. (2000) Review of the Status of Introduced Non-Native Waterbird Species in the Agreement Area of the African-Eurasian Waterbird Agreement Research Contract CR0219. BTO Research Report No. 299, BTO, Thetford.

Maclean, I.M.D. & Rehfisch, M.M. (2008) Guidelines on the measures needed to help birds adapt to climate change. AEWA Technical Series No. 26, African-Eurasian Waterbird Agreement Secretariat, Bonn, Germany.

Maclean, I.M.D., Rehfisch, M.M., Delany, S. & Robinson, R.A. (2008) The Effects of Climate Change on Migratory Waterbirds within the African-Eurasian Flyway. BTO Research Report No. 486, BTO, Thetford.

Maclean, I.M.D., Rehfisch, M.M. & Robinson, R.A. (2008) Migratory waterbirds and climate change: summary for policy makers. African-Eurasian Waterbird Agreement Secretariat, Bonn, Germany. Available

here.