Learn About Gyr Falcon
The Gyr Falcon (Falco rusticolus), or Gyrfalcon, is the largest of all falcon species. It breeds on Arctic coasts and islands of North America, Europe and Asia. It is the official bird of the Northwest Territories.
Males are 48 to 61 cm (19 to 24 in) long, weigh 805 to 1350 g (1.8 to 3 lbs) and have a wingspan from 110 to 130 cm (43 to 51 in). Females are rather bulkier and larger at 51 to 65 cm (20 to 26 in) long, a weight of 1180 to 2100 g (2.6 to 4.6 lbs) and have a wingspan ranging from 124 to 160 cm (49 to 64 in).
Plumage is very variable in this highly polymorphic species: the typical morphs are called “white”, “silver”, “brown” and “black” though coloration spans a continuous spectrum from nearly all-white birds to very dark ones.
The Gyrfalcon is a bird of tundra and mountains, with cliffs or a few patches of trees. It feeds only on birds and mammals. It usually hunts in a horizontal pursuit. Most prey is killed on the ground, whether they are captured there or, if the victim is a flying bird, forced to the ground.
The Gyrfalcon almost invariably nests on cliff faces. Breeding pairs do not build their own nests, and often use a bare cliff ledge or the abandoned nest of other birds, particularly Golden Eagles and Common Ravens. The clutch ranges usually from 2 to 4. The incubation period averages 35 days.
The only natural predator of gyrfalcons are Golden Eagles and even they rarely engage with these formidable falcons. Gyrfalcons have been recorded as aggressively harassing animals that come near their nests.
Humans, whether accidentally (automobile collisions or poisoning of carrion to kill mammalian scavengers) or intentionally (through hunting), are the leading cause of death for Gyrfalcons. Gyrfalcons that make it to adulthood can live up to 20 years of age.
- Kingdom: Animalia
- Phylum: Chordata
- Class: Aves
- Order: Falconiformes
- Family: Falconidae
- Genus: Falco
- Subgenus: (Hierofalco)
- Species: F. rusticolus
References: * BirdLife International (2004). Falco rusticolus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006. Database entry includes justification for why this species is of least concern. * Emslie, Steven D. (1985): The late Pleistocene (Rancholabrean) avifauna of Little Box Elder Cave, Wyoming. Rocky Mountain Geology 23(2): 63-82. * Helbig, A.J.; Seibold, I.; Bednarek, W.; Brüning, H.; Gaucher, P.; Ristow, D.; Scharlau, W.; Schmidl, D. & Wink, Michael (1994): Phylogenetic relationships among falcon species (genus Falco) according to DNA sequence variation of the cytochrome b gene. In: Meyburg, B.-U. & Chancellor, R.D. (eds.): Raptor conservation today: 593-599. * Howard, Hildegarde (1971): Quaternary Avian Remains from Dark Canyon Cave, New Mexico. Condor 73(2): 237-240. * Miller, Loye H. (1927): The Falcons of the McKittrick Pleistocene. Condor 29(3): 150-152. * Miller, Loye H. (1935): A Second Avifauna from the McKittrick Pleistocene. Condor 37(2): 72-79. * Nittinger, F.; Haring, E.; Pinsker, W.; Wink, Michael & Gamauf, A. (2005): Out of Africa? Phylogenetic relationships between Falco biarmicus and other hierofalcons (Aves Falconidae). Journal of Zoological Systematics and Evolutionary Research 43(4): 321-331. * Royal Alberta Museum (2006): Dragon Bytes: Did you know about time’s arrows?. Version of October 12, 2006. Retrieved 2007-AUG-13.+ * Snow, David W.; Perrins, Christopher M.; Doherty, Paul & Cramp, Stanley (1998): The complete birds of the western Palaearctic on CD-ROM. Oxford University Press. * White, Clayton M. (1994): 58. Gyrfalcon. In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (editors): Handbook of Birds of the World, Volume 2 (New World Vultures to Guineafowl): 274, plate 28. Lynx Edicions, Barcelona. * Wink, Michael; Seibold, I.; Lotfikhah, F. & Bednarek, W. (1998): Molecular systematics of holarctic raptors (Order Falconiformes). In: Chancellor, R.D., Meyburg, B.-U. & Ferrero, J.J. (eds.): Holarctic Birds of Prey: 29-48. Adenex & WWGBP. * Wink, Michael; Sauer-Gürth, Hedi; Ellis, David & Kenward, Robert (2004): Phylogenetic relationships in the Hierofalco complex (Saker-, Gyr-, Lanner-, Laggar Falcon). In: Chancellor, R.D. & Meyburg, B.-U. (eds.): Raptors Worldwide: 499-504. WWGBP, Berlin.