A 3-month-old, captive-bred gyrfalcon (Falco rusticolus
) of unknown sex was presented for acute respiratory distress and voice change of < 12-hour duration.
Other changes in cliff-nesting raptor occurrence included a decrease in occupied Gyrfalcon (Falco rusticolus
) territories from four in 1977 to one in 1979 and two in 2008, a decrease in Rough-legged Hawk (Buteo lagopus) nests from one in 1979 (none in 1977) to none in 2008, and increases in Golden Eagle (Aquila chrysaetos) nests, from two in 1977 and 1979 to five in 2008.
Birds of prey seem to be particularly susceptible to HPAIV infection (10), including the HPAIV H5N8 virus that killed captive gyrfalcons (Falco rusticolus
) that were fed infected duck carcasses (7).
In addition, Prairie Falcons (Falco mexicanus; Wyoming), Gyrfalcons (Falco rusticolus
; Alaska), and Golden Eagles (Aquila chrysaetos; Alaska) have responded to the female Peregrine Falcon eechup call.
JER FALCON (Falco Rusticolus
) COLUMBIA JAY (Coruus Bullockii) WHITE PELICAN (Pelecanus Erythrorhynchos) FISH HAWK (Pandion Haliaetus) WHOOPING CRANE (Grus Americana) CALIFORNIAN VULTURE (Pseudogryphus Californianus) WHITE HEADED EAGLE (Haliaeetus Leucocephalus) HUNTER John James Audubon shot the birds in the American wilderness SNOWY OWL (Bubo Scandiacus) BIRD OF PAY Sotheby's worker Mary Engleheart & the rare copy of the 19th century work, valued at up to pounds 6million
Among its next of kin are the kestrel (Falco sparverius), merlin (Falco columbarius), prairie falcon (Falco mexicanus), and gyrfalcon (Falco rusticolus
Radiographic measurement of internal organs in gyr falcons (Falco rusticolus
) and gyr peregrine hybrids (Falco rusticolus
X Falco peregrinus).
domestica), 2 mice (Mus musculus domesticus), 2 northern goshawks (Accipiter gentilis), and 2 Gyr-Saker hybrid falcons (Falco rusticolus
x Falco cherrug).
Further examination and comparisons using museum specimens resulted in a total of six identifications: Anatidae, eagle (Aquila or Haliaeetus), gyrfalcon (Falco rusticolus
), white-tailed ptarmigan (Lagopus leucurus), short-eared owl (Asio flammeus), and northern flicker (Colaptes auratus luteus).
The prevalence of Caryospora species among the various falcon species in this study was: gyr X peregrine hybrid falcons (Falco rusticolus
X Falco peregrinus), 27.3%; gyr falcons (Falco rusticolus
), 25.6%; peregrine falcons (Falco peregrinus), 20.5%; saker falcons (Falco cherrug), 16.5%; gyr X saker hybrid falcons (Falco rusticolus
X Falco cherrug), 8.1%; Eurasian kestrels (Falco tinnunculus), 1%; red-napped shaheen (Falco pelegrinoides babylonicus), 0.7%; and American kestrels (Falco sparverius), 0.3%.
We studied gyrfalcon (Falco rusticolus
) food delivery and feeding behavior during the nestling period in central West Greenland during the 2000 and 2001 field seasons.
This falcon belonged to a group of healthy peregrine falcons (n = 8) and gyrfalcons (Falco rusticolus
) (n = 7) with ages between 1 and 17 years.