Unusually warm January temperatures have enticed record numbers of migratory birds to remain in Finland.
BirdLife Finland member Marko Pohjoismäki has been birdwatching in Central Ostrobothnia for over 40 years, said that a few decades ago there were 30-50 different species that spent the winter in the region.
But over the past few winters, more than 100 different species have been spotted.
"It is really an exceptional change. As the weather warms birds are migrating later, or not at all, as the waterways stay thawed," Pohjoismäki said.
Birdwatchers in Central Ostrobothnia have seen large numbers of migratory birds who have stayed behind, especially aquatic birds such as goosanders (Mergus merganser) and common goldeneyes (Bucephala clangula). There have also been the first winter sightings of both black-throated and red-throated loons (Gavia-arctica and -stellata).
Dozens of swans have also been seen in the area.
"Temperatures this January have been 5-10 degrees above normal and that has consequences. The higher temperatures affect the birds' hormones, and even mating rituals are being seen by some great tits (Parus Major), blue tits (Cyanistes caeruleus), greenfinches (Chloris chloris), crows and magpies," Marko Pohjoismäki said.
"This weather could trigger nesting, and if the chicks hatch too early and cold weather hits, that would be bad," Pohjoismäki adds.
Warmer weather has already brought a few new species to Finland that usually nest in southern or central parts of Europe. For example, a pair of great egrets (Ardea alba) was discovered nesting in Finland for the first time in 2018.