Territory turnover, reproduction and human persecution in a population of goshawk Accipiter gentilis Revierbesetzung, Reproduktion und menschliche Verfolgung in einer Population des Habichts Accipiter gentilis
Bezzel, E.; Rust, R.; Kechele, W.
Journal fuer Ornithologie. Oktober; 1384: 413-441
In southern Bavaria all Goshawk Accipiter gentilis territories were checked in an area of 6690 km2 during a long-term study. The number of breeding pairs fluctuated within short periods, the percentage of females breeding only once increased. 1989-1997 the number of breeding pairs decreased from 83 to 34. The average annual reproduction was 1.59 per female, for females breeding once 1.14, for females breeding at least in two (up to 12) consecutive years 2.04. The 'lifetime' reproduction per female was 2.44. Among 489 females 21% had no offspring, whereas ca. 16% produced 50% of the total offspring (including single females with more than 20 fledglings). Sex ratio among nearly fullgrown nestlings was balanced, varying with annual reproduction rate. The breeding population suffers from modern forestry management and regular persecution particularly in areas with released Pheasants. Regional differences in turnover among territorial Goshawks and reproduction rates could be mapped. Core areas for the population form only minor parts of the area inhabited by breeding Goshawks.