Ambient Temperature and the Daily Energetics of Two Species of Hummingbirds, Calypte anna and Selasphorus rufus

@article{Beuchat1979AmbientTA,
  title={Ambient Temperature and the Daily Energetics of Two Species of Hummingbirds, Calypte anna and Selasphorus rufus},
  author={Carol A. Beuchat and Susan Budd Chaplin and Martin L. Morton},
  journal={Physiological Zoology},
  year={1979},
  volume={52},
  pages={280 - 295}
}
Anna (Calypte anna) and rufous (Selasphorus rufus) hummingbirds exhibited regular diurnal changes in body mass, locomotor activity (flight time and frequency), and feeding activity (frequency and consumption) at ambient temperatures (Ta) from 38 to −1 C. Body mass of both species increased gradually throughout the day and amounted to increases of as much as 16.4% in C. anna (7 C) and 10.8% in S. rufus (22 C). These changes in body mass were related to marked decreases in flight expenditure in… 
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