how now brown owl?

Tawny owls turn brown to survive in warmer climates, according to scientists in Finland. Feather colour is hereditary, with grey plumage dominant over brown. But the study, published in the journal Nature Communications, found that the number of brown owls was increasing. As winters become milder, the scientists say, grey feathered tawny owls are likely to disappear.

This study indicates that the birds are evolving in response to climate change. Climate-driven selection has led to an evolutionary change in the population. Dr Patrik Karell from the University of Helsinki, who led the study, gathered together data from long-term tawny owl studies carried out across Finland over the last 30 years.
BBC News, 22/2/11