Effects on rural House Sparrow and Tree Sparrow populations by experimental nest-site addition
While rural House Sparrows (Passer domesticus) have declined in Sweden, the population of the related Tree Sparrow (P. montanus) has remained stable, suggesting that they are affected by different population regulating mechanisms. Here we investigated if the two species differ in degree of nest-site limitation. After conducting an initial survey of both species on farmsteads in southern Sweden, we