Northern Goshawk (Accipiter gentilis) Science Article 3 abstract Age-dependent breeding performance is arguably one of the best-documented phenomena in ornithology.The existence of age-related trends has major implications for life-history theory, but the proximatereasons for these patterns remain poorly understood. It has been proposed that poor breeding performanceof young individuals might reflect lack of foraging skills.We […]

Northern Goshawk (Accipiter gentilis) Science Article 6 abstract Northern goshawks (Accipiter gentilis; hereafter, goshawks) occurthroughout forests of North America and have received muchattention as a target species for management (Reynolds et al. 1992,Iverson et al. 1996, Andersen et al. 2003). Goshawks nest in foreststands with high timber volumes and dense overstory canopiesabove relatively open understories […]

Northern Goshawk (Accipiter gentilis) Science Article 4 abstract The Northern Goshawk Accipiter gentilis typically prefers woodland habitat for nesting and hunting. In recent decades, however, the species has started colonising urban environments across Europe. Here I present the first study on the ranging behaviour of urban-breeding Goshawks. Each year from 1997 to 1999, I tracked […]

Northern Goshawk (Accipiter gentilis) Science Article 1 abstract While many studies have shown that patterns of partial brood loss often differ with offspring sex, food availability or between years, the question of whether family-size adjustment varies between sites has achieved little attention. I investigated this in Finnish northern goshawks Accipiter gentilis, and found that partial […]

Northern Goshawk (Accipiter gentilis) Science Article 5 abstract Age at first breeding has a large influence on fitness and hence is crucial to the evolution of life-history strategies. Goshawks Accipiter gentilis start breeding aged 1-4 years. Using 30 years of data and both lifetime reproductive success (LRS) and lind as a fitness estimate for 74 […]

Northern Harrier (Circus cyaneus) Science Article 4 abstract Hen Harriers Circus cyaneus and Montagu’s Harriers Circus pygargus are medium-sized raptors that differ in size (Hen Harrier being slightly bigger than Montagu’s Harrier) and breeding system (Montagu’s Harriers are semi-colonial and Hen Harriers defend nesting-hunting territories). In contrast, the diets of the two species when in […]

Montagus Harrier (Circus pygargus) Science Article 1 abstract The copulatory behavior of the monogamous Montagu’s Harrier (Circus pygargus) was studied between 1992 and 1995 near Madrid, Spain. Copulations started around 20 days before laying, and typically stopped at the end of the laying period. Copulation frequency peaked just before the start of the laying period, […]

Montagus Harrier (Circus pygargus) Science Article 6 abstract The feeding of Montagu’s Harriers Circus pygargus during the breeding period was studied in relation to the land-use systems (agricultural or pasture-lands) in pseudosteppe areas of Extremadura (SW Spain). A total of 1,180 prey items was identified from the combined analysis of pellets and prey remains collected […]

Montagus Harrier (Circus pygargus) Science Article 5 abstract Hen Harriers Circus cyaneus and Montagu’s Harriers Circus pygargus are medium-sized raptors that differ in size (Hen Harrier being slightly bigger than Montagu’s Harrier) and breeding system (Montagu’s Harriers are semi-colonial and Hen Harriers defend nesting-hunting territories). In contrast, the diets of the two species when in […]

Montagus Harrier (Circus pygargus) Science Article 4 abstract Autumn migration routes of two Dutch female Montagu’s Harriers (Circus pygargus) were documented for the first time using satellite telemetry. Both migrated to their African wintering area