Coastal survey highlights change in wintering wader populations


The findings from a survey of the wintering waders on the UK's non-estuarine coast has revealed significant changes in the numbers of several species, including Northern Lapwing, Eurasian Curlew, Common Redshank, Ruddy Turnstone and Sanderling.

The UK's wetlands, estuaries and non-estuarine coast are of international importance for the numbers of non-breeding waterbirds that they support. However, the UK's 17,000 km of non-estuarine coast is important too, but impossible to cover annually. For this reason, periodic surveys of such coastline are needed if scientists are to secure a complete picture of these important waterbird sites

The survey found Eurasian Oystercatcher densities were highest in Wales (Jonathan Bull).

During the winter of 2015-16, volunteers surveyed 9,183 km of non-estuarine coast (53% of the total length), with the greatest proportion of this incredible effort (5,699 km) delivered in Scotland. From these data, researchers at the BTO were able to calculate measures of waterbird abundance and distribution, revealing just how important this habitat is for wintering populations.

In terms of absolute numbers, Scotland has consistently supported the majority of the population across all non-estuarine waterbird surveys for Eurasian Oystercatcher, Ringed Plover, European Golden Plover, Northern Lapwing, Purple Sandpiper, Bar-tailed Godwit, Eurasian Curlew, Common Redshank and Ruddy Turnstone. Although this is likely to reflect the relative length of the coastline for Scotland (12,714 km) compared to England (2,705 km), Wales (1,185 km) and Northern Ireland (328 km), Purple Sandpiper, Eurasian Curlew, Redshank and Ruddy Turnstone still appear to show a bias towards Scotland.

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The survey work also revealed that Eurasian Oystercatcher densities were higher in Wales than in England, Scotland or Northern Ireland. Wales and other western parts of the UK host a greater proportion of wintering individuals from the Icelandic and Faroese breeding populations.

Although smaller in absolute numbers than Scotland, densities of Ringed Plover and Sanderling were highest in England. Grey Plover winter in larger numbers towards south-east Britain, and numbers were highest in England.

The survey also revealed that there have been significant declines in abundance for four species: Northern Lapwing (-57%), Euraisan Curlew (-31%), Common Redshank (-37%) and Ruddy Turnstone (-32%), with only Sanderling (+79%) appearing to have increased since the previous survey in 2007-08.

Co-author on the report and Wetland Bird Survey (WeBS) National Organiser, Dr Teresa Frost, commented: "The wintering populations of many of these species are drawn from different races, often breeding in different parts of the world and the relative distributions of these around the UK are only partially understood. 

"Being able to carry out periodic surveys across the non-estuarine coast is important, not just to complete the picture of total wintering waterbird numbers, but also to highlight the changing fortunes of birds that might be from different populations to those wintering on our wetlands and estuaries, typically covered by the WeBS scheme."