The effect of thermoregulatory substitution on optimal energy reserves of small birds in winter

JM McNamara, J Ekman, AI Houston

Research output: Contribution to journalArticle (Academic Journal)peer-review

16 Citations (Scopus)

Abstract

Previous models have predicted the body mass of small birds in winter on the basis of a trade-off between starvation and predation. Many of these models have assumed that energy expenditure while active increases with body mass. The implications of the fact that the metabolic cost of activity can substitute for internal heat production and help keep the bird warm have not been investigated. In this paper we show that if thermoregulatory substitution occurs then there is a critical level of energy reserves above which an active bird is thermoneutral. This critical level increases as temperature decreases. Below this level, substitution of energy results in higher optimal levels of reserves than would be predicted in the absence of substitution. Our model thus predicts that at low temperatures body mass will be higher when thermoregulatory substitution occurs.
Translated title of the contributionThe effect of thermoregulatory substitution on optimal energy reserves of small birds in winter
Original languageEnglish
Pages (from-to)192 - 196
JournalOikos
Volume105 (1)
Publication statusPublished - Apr 2004

Bibliographical note

Publisher: Blackwell Munksgaard
Other identifier: IDS number 801HS

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