Urbanization and nest-site selection of the Black-billed Magpie (Pica pica) populations in two Finnish cities: From a persecuted species to an urban exploiter

Urbanization is an important ecological factor that modifies the living conditions of species at multiplelevels. Urbanization is also influenced by human-animal relationships. We studied the effects of human-related factors on nest site selection of the Eurasian Magpie (Pica pica) by using both historical andcontemporary data on the nest sites of the Magpie both at landscape and micro-habitat levels in Finland.The nest site data on the Magpie were collected by searching old nest site data as well as by collectingdata from current nest sites in two Finnish towns. Our results indicate that the population densities ofthe Magpie have increased in both study areas during 1950–2010, and that the actual adjustment tourban conditions began around 1980. The relative nest height of Magpies has decreased in urban, butno in rural habitats. The Magpie preferred breeding sites with great green area cover and less built-upareas. Moreover, Magpies preferred ever-green coniferous trees over deciduous tree species as their nestsites. The Magpie made its nest in the upper parts of the tree canopies, regardless of the tree species. Ourresults support the idea that urbanization by the Magpie is related both to changes in human disturbance,and to species-specific habitat needs. Planting coniferous trees may promote the breeding of the Magpiein urban environments in northern areas. We suggest that, the Magpie, as a common and well-knownspecies, may be a good candidate to monitor the state of the urban environment.