Gyrfalcon, Falco rusticolus is a species of falcon in the Falconidae family. It is a very large, heavy-bodied, broad-necked falcon. It displays sexual dimorphism, the females being larger than the males and they are the largest falcons. It comes in three colour morphs: white[nb 1], grey and dark.
The Gyrfalcon's tail is very broad and moderately long; wings fairly long and broad-based for a falcon; outer wing tapers to a blunt tip. It tail length equals that of its wing width.
^ abcdeStokes, Donald W. and Stokes, Lilian Q. (2010). Stokes Field Guide to the Birds of North America. Little, Brown and Company. ISBN9770316010504 Check |isbn= value: invalid prefix (help). CS1 maint: Multiple names: authors list (link)
^ abcLiguori, Jerry; Pete Dunne (2011). Hawks at a Distance: Identification of Migrant Raptors. Princeton, NJ: Princeton University Press. p. 3. ISBN0691135592.Cite uses deprecated parameter |coauthors= (help); |access-date= requires |url= (help)
^ abcClark, William S.; Brian K. Wheeler (2011). Hawks of North America, 2nd Edition. Boston, MA: Houghton Mifflin Company. p. 12. ISBN0395670675.Cite uses deprecated parameter |coauthors= (help); |access-date= requires |url= (help)
^ abFrances, Peter; et al. (2007). Bird: The Definitive Visual Guide. Dorling Kindersley Inc. ISBN1564582957. CS1 maint: Explicit use of et al. (link)
^Peterson, Roger Tory (1980). A Field Guide to the Birds East of the Rockies. Houghton Mifflin Company. ISBN039526619X.
^Called "light" in Stokes Field Guide to Birds of North America
This article is part of Project Aves, a All Birds project that aims to write comprehensive articles on each bird, including made-up species.