25 February 2011
Scientists in Finland say warmer winters in recent years are causing some of the country's owls to change colour. Research done at the University of Helsinki suggests brown owls are better able to survive the warmer weather than grey-feathered owls.
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Despite their name, tawny owls actually come in two colours. And in Finland, the freezing, snowy winters give pale grey birds a camouflage advantage over their darker brown-feathered counterparts. But as the Finnish winters get milder, the grey owls are disappearing.
The University of Helsinki team gathered 30 years' worth of genetic and population data on tawny owls. They found that the birds inherited their plumage colour from their parents. The grey tawnys, as well as being better hidden from predators in the snow, seem to be endowed with other genetic advantages that make them healthier and stronger. But despite this, the brown owl population is now overtaking that of the greys, because the warmer winters have improved the brown owls' chances of survival.
The lead researcher, Dr Patrik Karell, said that this showed that the birds were evolving in response to climate change, so the tawny owl gene pool is actually getting browner. This is the first evidence of climate change having such an effect in the animal kingdom.
Victoria Gill, BBC News
Click to hear the vocabulary:
- tawny owls
a kind of owl, which is either brown or grey (although the colour tawny on its own usually means yellowish-brown)
- a camouflage advantage
a better disguise or way of hiding
here, other tawny owls
- plumage colour
- endowed with
- in response to
in reaction to
- gene pool
set of genes or genetic code (for a species)
- the animal kingdom
the set of all animals