Comparative energetics of divergent foraging modes: a doubly labelled water experiment on hummingbird competition
Article Abstract:
The energetics of foraging behavior of hummingbirds engagedin food competition was measured to determine interspecific differences in responses. Heterospecific pairs of hummingbirds competed for limited food in a big flight cage. The dominant territorial species strongly defended the feederswhen these were tightly clustered, thus limiting access by the subordinate species. This resulted in high mass-specific rates of energy intake and a balanced energy budget for the former and low food intake and high energy expenditure for the latter. When feeders were scattered, the subordinate species succeeded in getting food, but failed to maintain energy balance.
Publication Name: Animal Behaviour
Subject: Zoology and wildlife conservation
ISSN: 0003-3472
Year: 1992
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Foraging site displacement in common crane flocks
Article Abstract:
Foraging rates of aggressor and victim cranes, Grus grus, based on intraspecific kleptoparasitism predicted from the optimal foraging theory were examined in 324 aggressive displacements observed in feeding flocks. Prior to an attack, the intake of the aggressor was lower than the mean for the flock and lower than the minimum intake for basal metabolism. After the attack, the intake rate of the aggressor is more than the flock average. The reverse takes place for the victim. Kleptoparasitic strategies appear to be a response to temporary feeding rate reductions.
Publication Name: Animal Behaviour
Subject: Zoology and wildlife conservation
ISSN: 0003-3472
Year: 1998
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Costs and benefits of interspecific dominance rank: are subordinates better at finding novel food locations?
Article Abstract:
There is no major difference in the ability of dominant and subordinate species of tropical hummingbirds to discover unknown food locations. However, the dominant species is twice as fast as the subordinate species in finding novel food locations already discovered by a rival heterospecific cage-mate. This behavior may enable the dominant species to displace subordinates from newly found food sources in the wild. The experiments are conducted on a dominant species, Amazilia saucerottei, and a subordinate species, Chlorostilbon canivetii.
Publication Name: Animal Behaviour
Subject: Zoology and wildlife conservation
ISSN: 0003-3472
Year: 1996
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