Tiny Hawk (Accipiter superciliosus) Science Article 1 abstract This paper describes the hunting tactics of the Tiny Hawk, Accipiter superciliosusfontanieri, in a Costa Rican rain forest, where it appears to be a hummingbird specialist. Three tactics were used by the hawks to hunt hummingbirds: typical Accipiter still-hunting (probably not specifically for hummingbirds), waiting in ambush …
Tag Archive: all of Accipiter
Dec 27 2011
Causes and consequences of breeding dispersal in the Sparrowhawk Accipiter nisus
Sparrowhawk (Accipiter nisus) Science Article 1 abstract Sparrowhawks Accipiter nisus were present on particular territories for only one breeding season, but others were present on the same territory for up to eight seasons. Short periods of occupancy were due partly to mortality and partly to about one third of surviving birds of both sexes changing …
Dec 27 2011
A test of the condition-bias hypothesis yields different results for two species of sparrowhawks (Accipiter)A Test Of The Condition-Bias Hypothesis Yields Different Results For Two Species Of Sparrowhawks (Accipizter)
Sparrowhawk (Accipiter nisus) Science Article 2 abstract Determination of body condition of birds is important for many field studies. However, when using trapping methods based on food as a lure, the sample of trapped birds could be biased toward individuals in poor physical condition. We provide information on body mass, body condition, and sex and …
Dec 27 2011
WEIGHTS, BREEDING, AND SURVIVAL IN EUROPEAN SPARROWHAWKS
Sparrowhawk (Accipiter nisus) Science Article 5 abstract No significant diurnal variation in mean weight was detected in trapped European Sparrowhawks (Accipiter nisus). Weights of males fluctuated rather little through the year, but were highest in March and lowest in August. During the breeding cycle, males lost weight slightly in the prelay/early laying periods, when they …
Dec 27 2011
Age-related trends in the breeding success of individual female Sparrowhawks Accipiter nisus
Sparrowhawk (Accipiter nisus) Science Article 4 abstract Overall, female Sparrowhawks improved in the mean number of young they raised per year up to the 5th year of life, and then declined. An attempt is made to find to what extent this mean trend is caused by similar trends in the breeding of individual females, and …
Dec 27 2011
The abundance of essential vitamins in food chains and its impacton avian reproduction
Sparrowhawk (Accipiter nisus) Science Article 3 abstract Birds produce fewer or less viable eggs if the micro-nutrient requirements for reproduction cannot be met. Forexample, embryos from failed eggs of European sparrowhawks Accipiter nisus often show anomalies that indicate vitamin B2deficiency. B2 is only produced by plants and is propagated through the food chain. Here, egg …
Dec 26 2011
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 …
Dec 26 2011
Ecology of the Northern Goshawk in Fennoscandia
Northern Goshawk (Accipiter gentilis) Science Article 2 abstract Delayed density-dependent mortality induced by delayed numerical response of predators can drive prey populations to fluctuate in high-amplitude cycles. We studied numerical response of goshawks Accipiter gentilis to varying densities of their main prey (forest grouse) in western Finland during 1979_/1996. Occupancy rate of goshawk territories tracked …
Dec 26 2011
Age-dependent diet choice in an aviantop predator
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 …
Dec 26 2011
Northern Goshawk Diet During the Nesting Season inSoutheast Alaska
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 …
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