Finnish brown tawny owls have increased in number over the last 28 years compared to their grey counterparts. Research in Nature Communications this week suggests that populations of wild birds can evolve in response to climate change.

Patrik Karell and colleagues modelled the heritability of plumage colour in Strix aluco a Finnish tawny owl and found that almost 80% of the colour variation was heritable. They also modelled the survival of 466 owls. They found that brown owls have a lower survival rate compared to grey owls in winters where there was deep snow cover. As winters have been milder in recent years the numbers of the brown owls have increased, therefore the study shows that climate change can affect a heritable trait.