INNOCENTLY feeding wild birds in winter can alter their evolution, a study has shown.
One population of blackcaps has already begun to split into two separate species because of British bird-lovers, scientists have found.
In less than 30 generations, birds visiting UK gardens in winter have evolved different-shaped wings and beaks.
In time, they could eventually become a distinct species, say researchers – although in practice this was unlikely.
The birds breed side-by-side in the same central European forests, but began to follow different winter migration routes after some discovered rich pickings in the UK.
Eventually they divided into two reproductively separate groups.
One continued to fly south for the winter,
The other got into the habit of flying a shorter distance north-west to the UK.
