Energy regulation by traplining hummingbirds

Abstract

1. A published model of constant diurnal energy accumulation by territorial hummingbirds, does not accurately reflect the temporal distribution of feeding behaviour of traplining hummingbirds, Phaethornis longirostris (Long-tailed Hermit Hummingbirds). 2. In an enclosure study, gross nectar intake by P. longirostris decreased through the day, mirroring nectar production rates in its natural food-flowers and mimicking its natural foraging patterns. 3. Using a simulation model, the energetic consequences of constant and decreasing net energy intake rates for traplining hummingbirds are compared. 4. Given natural patterns of nectar production, model birds with decreasing diurnal net intake rates met their energetic needs with fewer flowers than those with constant net intake, and spent less time foraging. 5. It is concluded that P. longirostris do not satisfy the physiological assumptions of the published model, and that in this way they are different from the territorial species on which the model has previously been tested.