HYBRIDIZATION BETWEEN HOUSE SPARROW PASSER-DOMESTICUS AND TREE SPARROW PASSER MONTANUS

Hybridisation between House and Tree Sparrows is reported from islands off the coast of Northern Norway, including observed mating attempts in two different mixed pairs, and the breeding success in a third mixe d pair. The biometrics of hybrid offsprings were intermediate between the parents. The hybridisation probably involve only inexperienced ind ividuals and may have been facilitated by the spatially division of th e population into small island subpopulations.