Animal Field Guide

American Kestrel

Falco sparverius
(Falconidae)

Global Rank: G5
State Rank: S5B

Agency Status
USFWS:
USFS: none
BLM: none

Adult males are slate-blue on their wings and the crown of their heads. The back is rufous with distinct dark brown horizontal barring. The tail is uniformly rufous with a black band on the end. The breast is buff to cream with light vertical streaking. The female is uniformly rufous on the back and wings with dark brown horizontal banding. The tail is similarly marked. The breast is buff with heavy rufous streaking. Both sexes have a dark vertical stripe below, in front of, and behind the eye, with an additional dark stripe farther back on the head. Juvenile males differ from adults in having a more heavily marked breast and brown-tipped feathers. Juvenile females are identical to adult females. American kestrels range from nine to 12 inches in length and have a wingspan of 20-24 inches (FWP). Pointed wings, reddish back and tail, two black stripes on each side of white sides of head; male has blue-gray wings; averages 27 cm long, 58 cm in wingspan (NGS 1983).

Merlins are slightly larger than kestrels. female merlins are not as rufous as female kestrels. male merlins have blue backs and wings. sharp-shinned hawks have more rounded wings, and have blue or brown backs and wings(fwp). differs from peregrine falcon, merlin, and aplomado falcon in having a reddish back and tail and double black marks on sides of head; peregrine falcon is much larger. smaller than the eurasian kestrel (averages 34 cm long), which has only a single black mark on each side of the head.

Bozeman area migration: 4/1-5/5 & 8/25-10/10, peaks 4/25 & 9/15.

American kestrels are found in nearly all habitats in Montana. Nests are often located in cavities in trees, banks, cliffs, and buildings. They also use man-made nest boxes. They usually hunt in open habitat. Kestrels often perch on overhead wires or posts while looking for prey, or hover in midair (FWP). In Bozeman area, summer birds are concentrated in the valley, but some birds are found far up mountain canyons (Skaar 1969); wintering birds tend to frequent irrigated areas (Skaar 1969).

During the summer, kestrels feed heavily on large insects such as grasshoppers. Other prey includes small birds, rodents, and snakes. During winter they feed primarily on small birds and rodents.

In the 1944 raptor survey, this species made up 49.8% of raptor population in Montana (Davis 1961). Near Fortine, it is described as decreasing in numbers in recent years.

Male kestrels arrive at nest sites before females. A prolonged and often noisy courtship in May results in three to seven eggs, which hatch after 28 to 30 days of incubation. The young fly when they are about a month old. Parents and young often stay together for up to a month after they leave the nest (FWP). Nesting occurs in May and June, with young out of nest in July (Davis 1961). Fortine area eggs laid from early May- early June; young left nests as early as July 20.