Kestrel (Falco tinnunculus) Science Article 6 abstract The hunting flight of the kestrel (Falco tinnunculus) consists of short bouts of flight at wind speed against the wind with the eyes in a fixed position relative to the ground, and of short flights from one such position to the next. High speed films taken with a […]
Category: Falconiformes
Sex and testosterone effects on growth, immunity and melanin coloration of nestling Eurasian kestrels
Kestrel (Falco tinnunculus) Science Article 10 abstract Sex differences in testosterone levels and sex-biased sensitivity to testosterone are the basis of some ideas postulated to account for sex-linked environmental vulnerability during early life. However, sex variation in circulating testosterone levels has been scarcely explored and never manipulated at post-natal stages of birds in the wild. […]
Inter-sexual differences in the immune response of Eurasian kestrel nestlings under food shortage
Kestrel (Falco tinnunculus) Science Article 2 abstract When resources are limited, parents should decide the optimal number, size, and sex of progeny, and offspring should decide the optimal allocation of resources to different costly functions, such as growth and immunity. We manipulated clutch sizes of Eurasian kestrels by one egg to estimate possible cumulative effects […]
Between cohort variation in dispersal distance in the European Kestrel Falco tinnunculus as shown by ringing recoveries
Kestrel (Falco tinnunculus) Science Article 8 abstract Ringing recoveries of European Kestrels from north-western Europe have shown that a very low proportion of this population is migratory, and that even large-distance movements can be attributed mainly to dispersal movements of young birds. Several studies have shown the importance of food availability on dispersal rates in […]
First evidence of sex differences in the durationof avian embryonic period: consequences forsibling competition in sexually dimorphic birds
Kestrel (Falco tinnunculus) Science Article 7 abstract Parental favoritism in birds would be enhanced if parents can control any egg feature influencing the ontogeny of the embryo during incubation. Egg size and composition may influence the duration of incubation and hatching periods, and eggs bearing embryos of different sex may differ in size and composition. […]
Eurasian Hobby density, nest area occupancy, diet, and productivity in relation to intensive agriculture
Hobby (Falco subbuteo) Science Article 1 abstract A Eurasian Hobby (Falco subbuteo) population of 13-18 breeding pairs was studied for 6 years from 1987 to 1995 in a 62 km2 study area located within the seasonal flood zones of the PO River plain in northern Italy and characterized by intensive farmland interspersed with poplar (Populus […]
Woodpigeons nesting in association with hobby falcons:advantages and choice rules
Hobby (Falco subbuteo) Science Article 2 abstract Many bird species nest in close association with other bolder and more aggressive birds which provideprotection against nest predators. The woodpigeons, Columba palumbus, that nest in poplar plantations inNorthern Italy are found almost exclusively clumped around hobby, Falco subbuteo, nests. Woodpigeonssettle in the area and build their nests […]
Diving speeds and angles of a gyrfalcon (Falco rusticolus)
Gyrfalcon (Falco rusticolus) Science Article 1 abstract An optical tracking device recorded the threedimensional paths of 11 dives by a 1.02 kg gyrfalcon, trained to dive to a falconer. The dives started at altitudes up to 500 m above the ground and were inclined at angles of 17-62 deg from the horizontal. The falcon controlled […]
Southern Extension to the Breeding Range of the Gyrfalcon,Falco rusticolus, in Eastern North America
Gyrfalcon (Falco rusticolus) Science Article 2 abstract We report the observation of four gyrfalcon (Falco rusticolus) nests and several adults south of the previouslyrecognized southern limit of the species’ breeding distribution in eastern North America. Our southernmost observation extendsthe known breeding range approximately 400 km to the south. The northern forest tundra biome could delineate […]
Gyrfalcon predation on ptarmigan: numerical andfunctional responses
Gyrfalcon (Falco rusticolus) Science Article 3 abstract Gyrfalcon predation on ptarmigan during the breeding season was studied innorth-east Iceland 1981