Falco mexicanus
(Prairie Falcon)

Physical Description:
17-20" (43-51 cm). Gray-brown above with white edging on feathers for a scaling effect. White below with dark, vertical streaks. Brown on top of head and white on neck; blackish, vertical streaks on cheeks. Yellow feet and dark bill. Undersides of wings show black wingpits in flight.

Similar Species- Peregrine Falcon

Song:
Hoarse, repeated whistle, sometimes incessant.

Distribution:
Breeds from southeastern British Columbia, southern Alberta, southern Saskatchewan, and northern North Dakota, south to Baja California, parts of southwestern U.S., and northern Mexico. Winters from breeding range in southern Canada, south to Baja California and northern Mexico.

Found in open situations in mountainous shrub steppe, or grasslands areas. In Idaho, breeds in shrub steppe and dry mountainous habitat, and winters at lower elevations.

Diet:
Feeds opportunistically on mammals, lizards, and birds. In southwestern Idaho, Townsend's ground squirrels are main prey item.

Ecology:
Nests on cliff, sometimes in old corvid or raptor nest. Rapidly pursues birds in flight, but usually captures prey on or near ground. May cache prey in vegetation, on ledge, or in small crevice or cavity (caching is most common during early brood rearing). Cumulative home range size increases from incubation to hatching period. Birds disperse from lower elevations after young fledge. Average home range in southwestern Idaho study was 49-73 km2; highest known nesting density in North America occurs in that area (recorded nesting densities: 23 pairs on 26 km of cliffs in Colorado; and 200 pairs in 130 km along Snake River). Annual mortality has been estimated at 74% in immatures, and 25% in adults. Southwestern Idaho study found construction and recreation activities had no detectable adverse effects on nesting Prairie Falcons.

Laying may begin as early as: February in Texas and Mexico; March in California, Washington, Arizona, and Oregon; and April in Montana and Wyoming. Female (usually) incubates 6 eggs for 29-33 days; male brings food (in southern Idaho study, maximum broods averaged 3.14 young/nest). In southwestern Idaho, from 1974-83, numbers fledged/pair ranged from 1.48-3.23. Young are tended by both parents, remain at nest site for 36-41 days, and first breed at 2 yr. (sometimes 1).

Conservation:

Element Code:	ABNKD06090
Status:	Protected nongame species
Global Rank:	G4
State Rank:	S5,NTMB
National Rank:	N5B,N5N

Important State References:
Holthuijzen, A.M.A. 1990. Behavior and productivity of nesting prairie falcons in relation to construction activities at Swan Falls Dam. Final Report. Idaho Power Co., Boise. 77pp.