The hummingbird's restraint: A natural model for weight control

1420-9071

Weight control ; energetics ; foraging ; territory

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary By day, a breeding male hummingbird gives priority to aerial performance over energy security, minimizing body weight gain to expedite flight activity. We observed behavior and monitored weight via perches on electronic balances in a territory with unlimited resources (artificial feeder). The male restricted his first feeding to less than 1/6 of crop capacity. In the ensuing 15 h, his body weight increased only 1% despite an unlimited resource of artificial nectar. This facilitated acceleration for pursuit and courtship flights and reduced energy cost. In 20 min at dusk, an intake of 34% of body weight provided adequate energy for temperature regulation all night. In July, cessation of territorial activity was accompanied by a regular upward drift of dawn weight, suggesting that weight had been regulated previously as a balance between expenditure and intake, perhaps without involving set-points.

Electronic Resource