Evening Nest-box Departure Times of Eastern Screech-Owls
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I observed 514 nest-box departures of 12 different individual Eastern Screech-Owls (Megascops asio), both males and females, at dusk in Falmouth, Massachusetts over a period of 12 years and compared their departure times to local sunset. Mean (+/- SD) delay after sunset was 21 +/- 12 min, identical for males and females, but longer than those reported for more southerly locations. Females departed significantly earlier on overcast evenings. Females advanced their departure times during the nestling period by as much as 2.6 min/day, on average, over a 25-day period. The observed differences in departure delays among populations in Texas, the Washington, D.C. area, and Massachusetts may be an expression of differences in behavior among subspecies of M. asio. Received 14 July 2010. Accepted 1 February 2011.