Winter Roost-Site Use by Female American Kestrels (Falco-Sparverius) in Louisiana

Roosting ecology of American kestrels (Falco sparverius) wintering in southcentral Louisiana was studied during the winters of 1988-89 and 1989-90. Twenty-eight roost sites were found for 26 kestrels. Twenty-four (85%) roost sites were man-made structures and four (15%) were natural roosts. Roost times averaged 2.1 +/- 0.15 (SD) min before sunset (N = 46). Median height of man-made roost perches was 5.0 m (N = 20, range = 2-50 m); mean height of natural roost perches was 6.3 +/- 2.94 m (N = 4, range = 3-10 m). Kestrels did not roost communally; however, a male and a female roosted together for at least 10 d just prior to spring departure. Man-made roosts seemed to be preferred by migrant, female kestrels in southcentral Louisiana, as few females utilized natural roosts. Within areas of sufficient foraging quality, man-made roost sites may be a limiting factor for migrating kestrels.