Seasonal Differences in the Response of Rufous Hummingbirds to Food Restriction: Body Mass and the Use of Torpor

• DOI: 10.2307/1368184
• Publication Date: 2007-01-23T01:20:00Z
• Authors: Sara M. Hiebert
• Keywords: Torpor; Hibernation

Daily food consumption of captive Rufous Hummingbirds (Selasphorus rufus) was restricted during two different seasons to determine the effect chronically reduced intake on body mass and role nocturnal torpor in promoting changes mass. 70-90% ad libitum levels for 15 days spring 30 summer. In spring, all birds (n = 4) showed increases both use restriction, although energy saved by using sufficient compensate lost through restriction only birds. As soon as feeding resumed, three four a decline reduction torpor. summer, 9) had higher masses at start experiment, reflecting normal seasonal fluctuations During spent less time torpid than most declined or no significant change. The initial response return included decreased and, contrast rapid increase Seasonal differences may reflect stress these high-altitude, high-latitude breeders short breeding season, when physiological behavioral consequences responding environmental interfere with success.