Thermoregulation under semi-natural conditions in two species of African barbets (Piciformes: Lybiidae)

Show simple item record McKechnie, Andrew E. Smit, Ben 2011-03-14T07:31:40Z 2011-03-14T07:31:40Z 2010-07
dc.description.abstract Torpor has been documented in a number of avian orders, but our understanding of the phylogenetic distribution of this phenomenon is far from complete, and several groups have yet to be investigated. We examined patterns of rest- and active-phase thermoregulation in Acacia Pied Barbets Lybius leucomelas and Crested Barbets Trachyphonus vaillantii held in outdoor aviaries, using surgically-implanted miniature data loggers to record body temperature (Tb). Both species exhibited large circadian rhythms of Tb, with maximum active-phase and minimum rest-phase Tb (ρTbmin) values of 42.3 ± 0.1 °C and 37.7 ± 0.6 °C, respectively, in Acacia Pied Barbets (n = 3) and 42.5 ± 0.4 °C and 37.0 ± 0.6 °C, respectively, in Crested Barbets (n = 5). Neither species exhibited any indication of torpor, despite being subjected to a food restriction treatment that is known to elicit torpor in other taxa. Instead, restricted feeding resulted in small but significant increases in the amplitude of circadian Tb rhythms, with ρTbmin values 0.3-0.6 °C lower than during ad libitum food availability. The responses of barbets maintained in aviaries may not, however, be representative of those of free-ranging individuals. Body temperature traces we obtained from Acacia Pied Barbets in a field laboratory in the Kalahari Desert reveal reductions in Tb to below 32 °C during the rest-phase, suggesting that in natural habitats this species may routinely exhibit facultative hypothermia. The amplitudes of circadian Tb rhythms we observed under seminatural conditions in both species are significantly greater than expected on the basis of an allometric equation based largely on Northern Hemisphere data, but are similar to those observed in other southern African species. en
dc.description.sponsorship This study was facilitated by funding from the University of Pretoria and the DST/NRF Centre of Excellence at the Percy FitzPatrick Institute to AEM. Permits to capture the birds were obtained from the relevant provincial conservation authorities (Gauteng and Northwest). All procedures involving animals were approved by the Animal Use and Care Committee of the University of Pretoria (Protocol EC016-08), and comply with current South African Laws. en
dc.identifier.citation McKechnie, A & Smit B 2010,'Thermoregulation under semi-natural conditions in two species of African barbets (Piciformes: Lybiidae)', Ostrich : Journal of African Ornithology, vol. 81, no. 2, pp. 97-102. [] en
dc.identifier.issn 0030-6525
dc.identifier.other 1727-947X (online)
dc.identifier.other 10.2989/00306525.2010.488384
dc.language.iso en en
dc.publisher Taylor & Francis en
dc.rights © NISC (Pty) Ltd en
dc.subject Torpor en
dc.subject Phylogenetic distribution en
dc.subject Phenomenon en
dc.subject Acacia Pied Barbets Lybius en
dc.subject Crested Barbets Trachyphonus en
dc.subject Treatment en
dc.subject Kalahari Desert en
dc.subject.lcsh Piciformes en
dc.subject.lcsh Capitonidae en
dc.subject.lcsh Body temperature -- Regulation en
dc.title Thermoregulation under semi-natural conditions in two species of African barbets (Piciformes: Lybiidae) en
dc.type Postprint Article en

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