Torpor in three species of Brazilian hummingbirds under semi-natural conditions

摘要: We measured body temperatures in three species of Brazilian hummingbirds, the Versicolored Emerald (Amazilia versicolor; mass 4.1 g), Black Jacobin (Melanotrochilus fuscus; 7.7 g) and Swallow-tailed Hummingbird (Eupetomena macroura; 8.6 during overnight exposure to natural conditions photoperiod ambient temperatures. All entered torpor. In both A. versicolor E. macroura, individuals torpor even if they had access feeders up time sunset. contrast, M. fuscus was less prone enter did so mainly it been fasting for more than two hours before Furthermore, often spent whole night torpor, whereas other a variable, short, period night. observed one bout single all species. suggest that multiple nocturnal torpors result from interruption normal pattern by some (unknown) external stimuli. Any interrupted always followed new entry into supporting view there is threshold below which hummingbirds must Our data also indicate these hummingbird might use are not energetically stressed.