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 […]
Category: Accipitriformes
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 […]
Long-term changes in nest defense intensity of the spanish Imperial Eagle Aquila adalberti.
Spanish Imperial Eagle (Aquila adalberti) Science Article 1 abstract This paper deals with the variations recorded in the nest defence of the Imperial Eagle Aquila adalberti after the declaration of Donana as a national park (Parque Nacional Donana, SW Spain) and the cessation of strong human pressure. Increases have been detected in the defence and […]
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 […]
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 […]
Notes on the Snail Kite in Surinam.
Snail Kite (Rostrhamus sociabilis) Science Article 1 abstract The coastal plain of Surinam the Snail Kite (Rostrhamus sociabilis) is the most numerous hawk wherever freshwater marshes occur. The cultivation of rice, which inundates large areas during part of the year, has undoubtedly expanded its feeding grounds. When the rice is growing the birds concentrate along […]
MOLLUSK PREDATION BY SNAIL KITES IN COLOMBIA
Snail Kite (Rostrhamus sociabilis) Science Article 4 abstract Snail Kites (Rostrhamus sociabilis sociabilis) observed along the lower Rio Magdalena in northern Colombia fed heavily on Pomacea chemnitzi but also took Marisa cornuarietis, a smaller species. The kites captured Pomacea preferentially over Marisa and had difficulties extracting Marisa from its shell. They also failed to extract […]
HUNTING BEHAVIOR, PREY SELECTION, AND ENERGETICS OF SNAIL KITES IN GUYANA: CONSUMER CHOICE BY A SPECIALIST
Snail Kite (Rostrhamus sociabilis) Science Article 5 abstract The hunting behavior, snail size selection, and time-activity patterns of non-breeding Snail Kites (Rostrhamus sociabilis sociabilis) were studied in Guyana rice fields. Kites spent 62% of the photoperiod perching, 19% foraging, 13% in maintenance activities, and 6% flying. As the day progressed, the percentage of daylight hours […]
Snail Kite Kleptoparasitism of Limpkins
Snail Kite (Rostrhamus sociabilis) Science Article 2 abstract Kleptoparasitism is defined as the stealing of food from an individual by another individual (Rothschild and Clay 1952). Interspecific kleptoparasitism occurs in many animal groups but is particularly widespread among birds, especially when individuals of different species regularly congregate at feeding areas (Brockmana nd Barnard 1979). BRUCE […]
SOME ASPECTS OF THE BREEDING BIOLOGY OF THE SNAIL KITE IN FLORIDA
Snail Kite (Rostrhamus sociabilis) Science Article 3 abstract The breeding biology of the Snail Kite was studied in Florida from 1968-1977 and intermittently from 1978-1980. Breeding occurred every month, but not in the same year. Peak egg-laying occurred from February through April or generally about 81 d before the onset of the rainy season in […]