Summary: SHORT COMMUNICATIONS
@2001 The Raptor Research Foundation, Inc.
WINTER ROOSTING BEHAVIOR OF AMERICAN KESTRELS
DANIEL R. ARDIA I
Department ofEnvironmental and ForestBiology,StateUniversity ofNew York Collegeof
Environmental Scienceand Forestry,Syracuse,NY 13210 U.S.A.
KEyWORDS:AmericanKestrel;Falco sparverius; nestboxes; and winter residents (Smallwood 1988), I sought to com-
roostingbehavior;sexdifferences;winter behavior. pare roosting behavior between males and females and
between year-round residents and winter residents.
During the nonbreeding season, a protected nightly
roostsitecan be critical to maintaining a positive energy METHODS
balanceand reducing predation risk (Walsberg 1986,At- Study Site. I conducted this study between November
kinson 1993). American Kestrels (Falcosparverius)winter 1994 and February 1995 in Berks and Lehigh counties,
acrossmuch of North America (Root 1988); however,lit- southeastern Pennsylvania (40055'N, 75ry5'W). Novem-
tle is known about their roosting behavior especially in ber wasconsidered the start of winter becausewintering
the portion of their range where climatic c~nditions may kestrels have established areas of use by this time (Ardia
..1997). The study area (approximately 800 km2) is a
be stressful (Bird 1988). MIlls (1975) suggestedthat the h k f II. h'll d " I d h. h ......patc wor 0 ro mg I s an larm an s, w IC consls~
presence ?f a suI~ble roost may be. a crlucal part of a primarily of open agricultural land (pasture and fields of