Free-ranging common nighthawks use torpor

Fletcher, Quinn E.; Fisher, Ryan J.; Willis, Craig K. R.; Brigham, R. Mark

doi:10.1016/j.jtherbio.2003.11.004

Cited by 16 publications

(16 citation statements)

References 25 publications

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“…Our study reiterates the importance of thermoregulatory data from wild, free-ranging populations when assessing the occurrence of torpor in birds Fletcher et al 2004;Lane et al 2004;Cooper et al 2008). That at least one owl species exhibits qualitatively similar patterns of heterothermy to caprimulgids provides further insight into the phylogenetic distribution of this phenomenon within the order Strigiformes.…”

Section: Discussionsupporting

confidence: 63%

“…Although the depth of the heterothermic bouts in African scops-owls varied between 3Њ and 9ЊC, the patterns were highly consistent, suggesting that these bouts represented a common physiological response. Moreover, the shallow torpor bouts in African scops-owls were more similar to the torpor bouts recorded in caprimulgids Körtner et al 2001;Fletcher et al 2004) than the patterns of rest-phase hypothermia (T b reductions !5ЊC) typically observed in passerines (Reinertsen 1996;McKechnie and Lovegrove 2003).…”

Section: Discussionsupporting

confidence: 57%

“…T skin patterns in African scops-owls closely resembled the torpor bouts recorded around sunrise in Australian owletnightjars, common nighthawks Chordeiles minor and whippoor-wills Caprimulgus vociferus Fletcher et al 2004;Lane et al 2004). Like many caprimulgids, African scops-owls are likely to undergo periods of energetic stress during cold winters when the availability of food resources (mainly arthropods) is reduced.…”

Section: Discussionmentioning

confidence: 57%

“…Many studies on caprimulgids have reported considerable interindividual variability in torpor use, with only small proportions of populations using pronounced torpor (Fletcher et al 2004;Lane et al 2004;McKechnie et al 2007). One source of uncertainty is that we obtained data from only male African scops-owls.…”

Section: Discussionmentioning

confidence: 95%

“…Data from free-living birds are particularly important in light of recent studies showing that many birds use torpor only under natural conditions Körtner et al 2001;Fletcher et al 2004;Lane et al 2004;Cooper et al 2008).…”

Section: Pearl-spotted Owlets and African Scops-owls Introductionmentioning

confidence: 99%

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Do Owls Use Torpor? Winter Thermoregulation in Free‐Ranging Pearl‐Spotted Owlets and African Scops‐Owls

Smit

McKechnie

2010

Physiological and Biochemical Zoology

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Numerous avian taxa use torpor, which involves pronounced reductions in body temperature (T b ) to below normothermic levels. However, the occurrence of this phenomenon in owls (Strigidae) remains largely unknown. We investigated winter patterns of thermoregulation in the crepuscular 80-g pearlspotted owlet Glaucidium perlatum and the strictly nocturnal 61-g African scops-owl Otus senegalensis by obtaining telemetric measurements of skin temperature (T skin ) from free-ranging individuals in the Kalahari Desert of southern Africa. Pearlspotted owlets remained homeothermic throughout the study period, whereas African scops-owls routinely used shallow torpor, with T skin reduced by 3.3Њ-8.6ЊC (pooled mean, 5.3Њ ‫ע‬ ) below normothermic levels for 3-4 h after sunrise. The 1.1ЊC mean lowest T skin recorded in three African scops-owl individuals was . The thermoregulatory differences be-29.0Њ ‫ע‬ 0.1ЊC tween these two species may be related to their diets and activity patterns. African scops-owls are almost exclusively insectivorous and experience a marked reduction in food availability on cold winter nights. In contrast, pearl-spotted owlets have more flexible activity patterns and include larger or diurnal vertebrate prey in their diet.

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Section: Discussionsupporting

confidence: 63%