Playback census of a breeding population of Little Owl, Athene noctua, in NW Lombardy (Varese province).

摘要

In the years 2006-2008, the authors investigated a breeding population of Little Owl, Athene noctua, in an urbanized area of NW Lombardy (Varese province). They employed the playback method along 5 transects with 36 points of emission: they obtained an overall response rate of 33.6%, with a mean density of breeding pairs of 0.5/km2, a value close to the Italian mean value for urbanized areas. The authors found a significant value of the G test for the spacing of the breeding territories (G=0.73 and G=0.81 respectively) in the years 2007 and 2008. Otherwise no correlation was found with urbanized noise level and response rate, but in the three years 2006-2008 only 8 census points were continuously occupied vs. 16 points never occupied and 12 points revealed a positive response only in one year. The authors analyzed with ArcView 3.2 the available habitat between occupied and unoccupied points, but the 1:10.000 cartography was too coarse to reveal exactly the habitat use of Little Owl in the urbanized habitat.