SPACING OF BIRDS OF PREY IN SOUTHERN FINLAND

Birds of prey were studied in central Uusimaa, southern Finland, durin g 1972-90. Eight diurnal species and six owl species bred regularly in the study area (of up to 4800 km2). As their food supply was relative ly stable, most long-term territorial (site-tenacious) species demonst rated even spacing of nesting places, while irregular patterns charact erized the widely fluctuating short-term territorial (nomadic) vole sp ecialists. Dispersion of traditional nesting places had a major effect on spacing of occupied locations. Irregularities in spacing of nestin g places were largely due to the uneven distribution of suitable habit ats. Avoidance of predation might have affected the spatial structure of the bird assemblage studied, while interspecific competitive effect s were less evident.