Italian Sparrow - Taxonomy

Taxonomy

The taxonomic status of the Italian Sparrow has been a matter of debate. It has been variously regarded as a stable hybrid between the House Sparrow and Spanish Sparrow, or as a subspecies of either the House or Spanish Sparrow. Many authorities, including the Handbook of the Birds of the World, recognise it as a separate species, if only for convenience. Others, including many conservation groups, consider the Italian Sparrow a simple hybrid and ignore it. The chromosomes of Italian Sparrows are distinct from those of the House Sparrow, but mitochondrial DNA suggest a close relation to the House Sparrow.

A DNA analysis by Jo Hermansen, Glenn-Peter Sætre, and a group of other scientists from Norway published in Molecular Ecology in 2011 indicates that the Italian Sparrow originated as a hybrid between House and Spanish Sparrows. It has mitochondrial DNA from both parent species. Additionally, it is now breeding beside the Spanish Sparrow without cross-breeding in areas where the species both occur. Although it hybridises with the House Sparrow in a sparsely populated contact zone in the Alps, the contact zone is characterized by relatively abrupt changes in species-specific male plumage, suggesting that partial reproductive isolation based on plumage may also have developed between these two taxa. As a genetically distinct group that is reproductively isolated from the parental species, it must be recognised as a separate species, according to Hermansen and colleagues.