Species of the Month: Whooper Swan Cygnus cygnus (October 2024)

Autumn sees the return of migratory birds which breed in the subarctic regions and return to the relatively mild conditions of western Europe to spend the winter months. Whooper Swans Cygnus cygnus are our largest regular migrant bird, and occur in internationally important numbers in SW Scotland. The yellow and black bill distinguishes them from all but their close cousin the Bewick’s Swan Cygnus columbianus bewickii, which is a scarce visitor to the region.

The Solway Estuary is of particular significance, regularly supporting nationally important numbers (>=1% of the Great Britain wintering population), with WWT Caerlaverock being the key location. Flocks may be encountered at other regular sites such as Wigtown Bay, Loch Ken and Threave. Although less common in Ayrshire, small flocks do occur throughout the winter period, with favoured sites including Fail, Bogton Loch and Garnock Floods. They occur irregularly at many other sites throughout the region. During the daytime birds often disperse to feed on agricultural land, and flocks can often be found grazing in fields well away from their overnight wetland roosts.

Whooper Swans are well studied, and compared to many species we know a considerable amount about their ecology, behaviour and movements. Much is down to the ability to recognise and study individuals; some birds carry coloured leg rings or neck collars, each bearing a unique letter/number combination which allows individual birds to be identified in the field. Recorders can contribute to research by reporting colour-ring sightings via the Euring portal.

Mark Pollitt

SWSEIC Manager