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 […]
Category: Accipitriformes
Age at first breeding and fitness in goshawk Accipiter gentilis
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 […]
Food-niche differentiation in sympatric Hen Circus cyaneus and Montagu’s Harriers Circus pygargus
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 […]
Habitat use by Hen Harriers Circus cyaneus on Orkney: implications of land-use change for this declining population
Northern Harrier (Circus cyaneus) Science Article 3 abstract The use of habitats by hunting Hen Harriers Circus cyaneus just prior to the settlement period was investigated on Orkney, where numbers have declined by 70% over the last 20 years. Both males and females hunted over areas that were closer to subsequent breeding territories. Neither sex […]
Movements of British Hen Harriers Circus cyaneus outside the breeding season
Northern Harrier (Circus cyaneus) Science Article 1 abstract Hen Harrier chicks were wing-tagged in four regions in Scotland and in North Wales between 1990 and 1995, and resighted or recovered dead as fully grown birds during the non-breeding season (August to April) throughout Britain and Ireland, and on the Continent, until April 1997. Results were […]
Veranderungen in der Zusammensetzung der PCB- und DDT-Gemische in verschiedenen Lebensstadien der Wiesenweihe (Circus pygargus) und der Rohrweihe (Circus aeruginosus) in Nordrhein-Westfalen, Deutschland
Northern Harrier (Circus cyaneus) Science Article 2 abstract Egg and liver samples of Montagu’s and Marsh Harriers from the 1990’s were examined for their burden of DDT and PCB. The DDT burden in both species was distinctly higher in the eggs than in juveniles and adults, whereby the values for the adults were clearly higher […]
Copulatory Behavior Of Semi-Colonial Montagu’s Harriers
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, […]
The diet of Montagu’s Harriers Circus pygargus in relation to land-use systems in pseudosteppe areas of Extremadura (SW Iberian Peninsula)
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 […]
Food-niche differentiation in sympatric Hen Circus cyaneus and Montagu’s Harriers Circus pygargus
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 […]
Satellite tracking of two Montagu’s Harriers ( Circus pygargus ): dual pathways during autumn migration
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