Feeding Evolution

“Bird-feeders, hung in many a garden, can affect the way our feathered friends evolve, say scientists. European birds called blackcaps follow a different “evolutionary path” if they spend the winter eating food put out for them in UK gardens. The birds’ natural wintering ground is southern Spain, where they feed on the fruits that grow there. Researchers describe the impact this well-intentioned activity has had on the birds in Current Biology journal. Dr Martin Schaefer from the University of Freiburg in Germany led the research. He and his team found that blackcaps that migrated to the UK for the winter were in the very earliest stages of forming a new species. He explained that some blackcaps (Sylvia atricapilla) would always have migrated ‘little further north’ than others and eventually ‘ended up in Britain in the winter. But those birds would have had nothing to eat,’ he said. It was when garden bird feeders became more popular in the UK that an evolutionary division began to emerge.”