White Gyrfalcon (Falco rusticolus candicans) at Wayland, Mass

The Auk ◽  
1932 ◽  
Vol 49 (2) ◽  
pp. 217-217
Keyword(s):  
Falco Rusticolus

Ненейтральная изменчивость цитохрома b у балобана Falco cherrug Grey, 1834 и кречета Falco rusticolus L.

2021 ◽  
Vol 57 (4) ◽  
pp. 454-463
Author(s):  
Д. Н. Рожкова ◽  
Л. С. Зиневич ◽  
И. В. Карякин ◽  
А. Г. Сорокин ◽  
В. Г. Тамбовцева ◽  
...  
Keyword(s):  
Falco Rusticolus ◽  
Falco Cherrug

Ecology of gyrfalcons, Falco rusticolus, in the central Canadian Arctic: diet and feeding behaviour

1988 ◽  
Vol 66 (2) ◽  
pp. 334-344 ◽  
Author(s):  
K. G. Poole ◽  
D. A. Boag
Keyword(s):  
Feeding Behaviour ◽  
Prey Species ◽  
Prey Availability ◽  
Optimal Foraging Theory ◽  
Ground Squirrels ◽  
Spermophilus Parryii ◽  
Falco Rusticolus ◽  
Lagopus Mutus ◽  
Spring Arrival ◽  
Average Size

Diet and aspects of feeding behaviour in a population of gyrfalcons (Falco rusticolus) in the Northwest Territories were examined between 1984 and 1986. Three prey species, rock ptarmigan (Lagopus mutus), arctic ground squirrel (Spermophilus parryii), and arctic hare (Lepus arcticus), composed 96.5% of total prey biomass identified. Ptarmigan and hares were taken in May and June of all years (98.2% of biomass). Juvenile squirrels were used extensively in July and August of 1984 and 1985 but not in 1986, when squirrel production fell to almost zero; ptarmigan continued to be the dominant prey species throughout that summer. Because densities of breeding ptarmigan remained relatively constant during the study, but those of juvenile ground squirrels did not, it appeared that gyrfalcons responded functionally to varying availability of prey. Mean weight (250 g) of prey taken by male gyrfalcons was significantly less than the weight (330 g) of prey taken by females. As predicted by optimal foraging theory, average size of prey brought to the nest increased as time away from the nest increased. Conditions of food abundance were observed at most nests, suggesting that the amount of food available during the nestling period was not limiting production. We suggest that annual production is a function of spacing of pairs, which is set during courtship and prelaying, when prey availability is at its yearly low and when males must forage for both members of the pair. The fact that most gyrfalcon pairs initiated laying only after the spring arrival of migrating ptarmigan is consistent with this conclusion.

scholarly journals Nonrandom territory occupancy by nesting Gyrfalcons (Falco rusticolus)

2019 ◽  
Vol 5 (3) ◽  
pp. 148-160
Author(s):  
David L. Anderson ◽  
Peter J. Bente ◽  
Travis L. Booms ◽  
Leah Dunn ◽  
Christopher J.W. McClure
Keyword(s):  
Site Selection ◽  
Spatial Scales ◽  
Site Occupancy ◽  
Brood Rearing ◽  
Falco Rusticolus ◽  
Occupancy Patterns ◽  
Information Gap ◽  
Competing Models ◽  
Nonrandom Pattern ◽  
Habitat Variables

We know little regarding how specific aspects of habitat influence spatial variation in site occupancy by Arctic wildlife, yet this information is fundamental to effective conservation. To address this information gap, we assessed occupancy of 84 Gyrfalcon (Falco rusticolus Linnaeus, 1758) breeding territories observed annually between 2004 and 2013 in western Alaska. In line with the theory of population regulation by site dependence, we asked whether Gyrfalcons exhibited a nonrandom pattern of site selection and if heterogeneous landscape attributes correlated with observed occupancy patterns. We characterized high- and low-occupancy breeding territories as those occupied more or less often than expected by chance, and we evaluated land cover at 1 and 15 km circles centered around nesting territories to identify habitat variables associated with observed occupancy patterns. We tested 15 competing models to rank hypotheses reflecting prey and habitat variables important to nesting Gyrfalcons. We confirmed a nonrandom pattern of site selection but found only weak evidence that the distribution of prey habitat was responsible for this pattern. We reason that preferential habitat use by nesting Gyrfalcons may be determined by spatial scales other than those we measured or may be driven by landscape-level attributes at time periods other than during the brood rearing period.

Normal haematological values in gyr falcons (Falco rusticolus)

2005 ◽  
Vol 157 (26) ◽  
pp. 844-847 ◽  
Author(s):  
J. H. Samour ◽  
J. L. Naldo ◽  
S. K. John
Keyword(s):  
Falco Rusticolus ◽  
Haematological Values
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