BBC Nature - Autumn’s birds delay migration
Geese, ducks and swans that spend winter in wetlands of Northern Europe are changing their migration patterns as temperatures rise, say scientists.
Researchers in Finland found some waterfowl delayed migrations by up to a month compared with 30 years ago.
The Wildfowl and Wetlands Trust (WWT) says that numbers of some very familiar species are decreasing in the UK, as many birds do not fly as far.
The study is published in the Journal of Ornithology.
Lead researcher Aleksi Lehikoinen from the University of Helsinki examined three decades’ worth of data from Hanko Bird Observatory in southern Finland.
Tufted duck (c) Petteri Lehikoinen The tufted duck showed the largest change in its migration, delaying by more than a month
Since 1979, volunteers there have been undertaking daily bird counts, to build up a “migration census”. This revealed which species were flying south from Finland and when.
The three-decade census revealed that “some species had been delaying their migration dates by as much as one month”, Dr Lehikoinen told BBC Nature.
Six species out of the 15 they counted set off significantly later; these included some traditional UK winter visitors, such as the greylag goose and the tufted duck.