BRITISH people's love of feeding birds in their gardens may have changed the evolution of a species, according to Oxford researchers.

Comparing nearly half a million pieces of DNA collected from Wytham Woods in north Oxford and two sites in the Netherlands, academics found that the British great tit has grown a longer beak than its European cousins.

The research, published in the journal Science suggests that the bird's bill has grown 0.4mm since the 1970s.

Birds with genetic variants for longer beaks were more frequent visitors to feeders than birds without the genetic variation.

The genetic changes are thought to be connected to having to reach past the wire mesh of the feeders to get hold of the food.

Britain spends about twice as much on bird seed as the rest of Europe.

The tradition dates back to the winter of 1980-91 when newspapers urged readers to feed starving birds.

The birds measured at Wytham were also more likely to raise more nestlings which is thought to be because they are better fed.

The report, produced in collaboration with researchers from other universities, is part of a long-term study on great tits in Wytham Woods.