Birdwatch

Help survey gulls

THE Winter Gull Survey (WinGS) has been run by the BTO for more than 50 years and over that period it has provided essential informatio­n about how our gull population­s are changing. BTO researcher­s are trying to determine the causes of population declines in Britain’s breeding gulls and to monitor those birds that arrive here from overseas. In autumn and winter, gulls roost communally on lakes, reservoirs and estuaries across the UK, in flocks that can number many hundreds or even thousands of birds. Understand­ing where these roosts occur, and the numbers of birds using them, is key to helping conservati­on organisati­ons protect them.

The last WinGS surveys were in 2005-06 when the most abundant gull species was Black-headed Gull, with at least two million wintering across the UK. Recent population estimates point to a decline of about 40%, with avian flu probably taking its toll.

To glean more informatio­n, the BTO is asking its volunteer counters to undertake an autumn count as well as the usual winter edition, as informatio­n on the whereabout­s of gulls following the breeding season is limited. Volunteers will visit establishe­d roost sites used by migrating and wintering gulls, as well as random sites across inland and coastal locations. Some gull species group in large concentrat­ions in the autumn before dispersing to their wintering areas and birders across the UK can help to identify the locations of such autumn aggregatio­ns and determine exactly how many gulls are using each site.

The key date for the autumn count is 29 September 2024 and any birders taking part must feel confident that they can count large numbers of birds accurately in the late afternoon with fading light. They must also be able to identify all gull species present, focusing on six key species in particular: Black-headed, Common, Lesser Black-backed, European Herring, Mediterran­ean and Great Blackbacke­d Gulls.

WinGS covers survey sites across the UK, plus on the Channel Islands and the Isle of Man. To find more details about the actual sites where volunteers are needed, together with more informatio­n about the survey, log on to www.bto.org/

wings. If you want to test your identifica­tion skills then the BTO has several online identifica­tion videos you can access from its ‘Develop your skills’ webpage (www.bto.org/develop-yourskills). There is also an article on ‘Accurately counting winter flocks’ in the ‘Field Craft articles’ section.