Scientists in Norway say they have conclusive genetic evidence that sparrows recently evolved a third species.
The Italian sparrow, they argue, is a cross between the ubiquitous house sparrow and the Spanish sparrow.
Whether it is a distinct species has been the subject of a long scientific debate.
The Oslo team say in the journal Molecular Ecology that their evidence resolves the question.
Many bird-watching guides already identify the Italian sparrow as a separate species.
But this study, led by evolutionary biologist Glenn-Peter Saetre from the University of Oslo, is a genetic snapshot that appears to settle the debate.
