Effects of building features on density and flock distribution of feral pigeon Columba livia var. domestica in an urban environment

We censused feral pigeons (Columba livia) living in Milan, Italy (a 181-km2 area), between July 1999 and February 2000 by means of linear transects to examine population densities in different urban habitats and the relationships between population density and structural features of buildings. The pigeon population of Milan was 103 650 birds, with an average density of 570/km2. Population density increased significantly from farmland (434 birds/km2) to the suburbs (604 birds/km2) and from the suburbs to the centre of the city (2083 birds/km2). There was a positive relationship between both bird number and flock number and the abundance of buildings constructed before 1936. There were no significant associations between either bird number or flock number and the abundance of buildings when we did not consider date of construction. This indicated active selection of old buildings by feral pigeons.