Tuesday, April 24, 2018

Why do birds stand on one leg? – A pilot study of exotic and native New Zealand birds

TitleWhy do birds stand on one leg? – A pilot study of exotic and native New Zealand birds
Publication TypeJournal Article
Year of Publication2010
AuthorsHarker, TD, Harker, RF
JournalNotornis
Volume57
Issue4
Pagination173-177
Type of ArticleFull article
Keywordsflamingo, low temperature responses, pied stilt, thermoregulation, unihemispheric slow wave sleep, USWS, waterfowl
Abstract

One-legged standing (or unipedal posture) in birds was investigated with a particular focus on the role of ambient air temperature on this behaviour in a variety of wading birds and waterfowl. Waterfowl (Anas platyrhynchos and Cygnus atratus) were less likely to be observed standing on 1 leg than long-legged species of wading birds (Ardea novaehollandiae, Limosa lapponica, Platalea regia, Himantopus himantopus), perhaps because of differences in the length of their legs. Feeding behaviour and activities associated with disturbance influenced the frequency of unipedal posture. For captive flamingos (Phoenicopterus roseus) and pied stilts (Himantopus himantopus) the proportion of birds observed standing on 1 leg increased as the temperature increased from 8 to 19C. This observation contradicts the theory that unipedal posture is a behavioural adaptation to minimise heat loss on cold days. An alternative theory based on unihemispheric slow wave sleep (USWS) patterns is proposed as an explanation for unipedal posture and is recommended as a focus for future research. Our results also confirm the importance of considering differences between species in leg anatomy and activity levels to measure the effects of temperature.

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