Author/Editor		Vrezec, Al
Title		Breeding density and altitudinal distribution of the ural, trawny, and boreal owls in north Dinaric Alps (central Slovenia)
Type		članek
Source		J Raptor Res
Vol. and No.		Letnik 37, št. 1
Publication year		2003
Volume		str. 55-62
Language		eng
Abstract		Ural (Strix uralensis), Tawny (Strix aluco), and Boreal owl (Aegolius funereus) density and altitudinal distribution were determined using playback to census owls on Mt. Krim (North Dinaric Alps, central Slovenia). Survey points were selected proportionally by altitude according to the relief of the area (820-1060 masl). Density of Ural Owls was estimated to be 2.2 territaries/10 km2; high relative to published data from Europe, while densities of Tawny (4.0 territories/10 km2) and Boreal owls (2.8 territories/ 10 km2) were in the range or fower than other European data. The Tawny Owis were found at signi6cantly lower altitudes (320-850 masl), while Boreal Owls were at higher altitudes (700-940 masl) than expected. I suggest that Ural Owl territories were located in suboptimal habitat for Tawny Owls. The segregation of these owts by altitude in temperate-zone, continuous-montane forests is either a consequence of competitive exclusion or predation. The similarity in altitudinal distribution between Tawny and Boreal owls was low, suggesting that Tawny Owl territories are not suitable habitat for Boreal Owls. At high altitudes, harsh conditions prevent the Tawny Owl from competing with the Ural Owl; an advantage for the Boreal Owt, which was capable of surviving harsh conditions within Ural Owl territories. Further studies are needed to determine competitive exclusion or predation interactions among these owls.
Descriptors		BIRDS ECOSYSTEM POPULATION DENSITY SLOVENIA