Daily Torpor in Free‐Ranging Whip‐Poor‐Wills (Caprimulgus vociferus)

@article{Lane2004DailyTI,
  title={Daily Torpor in Free‐Ranging Whip‐Poor‐Wills (Caprimulgus vociferus)},
  author={Jeffrey E. Lane and R. Mark Brigham and David L. Swanson},
  journal={Physiological and Biochemical Zoology},
  year={2004},
  volume={77},
  pages={297 - 304}
}
The use of heterothermy is well documented in the order Caprimulgiformes, but there is conflicting information regarding whether whip‐poor‐wills are heterothermic. Consequently, we sought to rigorously examine the thermoregulatory abilities of this species. Our study was conducted in southeast South Dakota (42°47′N, 97°0′W), where 35 individuals were captured and outfitted with external, temperature‐sensitive radio transmitters. We found evidence that whip‐poor‐wills used daily torpor during… 
Torpor in an African caprimulgid, the freckled nightjar Caprimulgus tristigma
TLDR
The results confirm the ability to use torpor by a nocturnal aerial insectivore from the Afrotropics, and reiterate the variability in patterns of torpor that can exist within a population.
Torpor use by Free-ranging Pallid Bats (Antrozous pallidus) at the Northern Extent of Their Range
TLDR
Torpor duration increased as mean daytime Ta decreased albeit the relationship differed between individuals and there was no significant effect of individual on the relationship between minimum Tskin during torpor and Ta.
Do Owls Use Torpor? Winter Thermoregulation in Free‐Ranging Pearl‐Spotted Owlets and African Scops‐Owls
TLDR
Winter patterns of thermoregulation in the crepuscular 80‐g pearl‐spotted owlet Glaucidium perlatum and the strictly nocturnal 61‐g African scops‐owl Otus senegalensis are investigated by obtaining telemetric measurements of skin temperature (Tskin) from free‐ranging individuals in the Kalahari Desert of southern Africa.
Do Owls Use Torpor ? Winter Thermoregulation in Free-Ranging
Numerous avian taxa use torpor, which involves pronounced reductions in body temperature (Tb) to below normothermic levels. However, the occurrence of this phenomenon in owls (Strigidae) remains
Heterothermy in Caprimulgid Birds: A Review of Inter- and Intraspecific Variation in Free-Ranging Populations
TLDR
Overall levels of heterothermy, as quantified using a recently proposed metric, do not show statistically significant relationships with M b nor with ecological variables such as minimum air temperature or habitat aridity, Nevertheless, it is striking that the two most heterothermic species recorded to date, the Common Poorwill and the Freckled Nightjar, both inhabit arid habitats.
Roost type influences torpor use by Australian owlet-nightjars
TLDR
It is shown that roost selection and thermal biology are strongly interrelated in determining energy expenditure and lower costs of arousal from torpor via passive rewarming and basking and decreased risk of predation are two possible explanations for the preference to roost in tree hollows.
Avian torpor or alternative thermoregulatory strategies for overwintering?
TLDR
Low BMR, communal roosting and insulation of the roost nest enable white-browed babblers to survive winter without resorting to torpor, suggesting heterothermia is not a common thermoregulatory strategy for passerine birds.
Environmental correlates of Freckled Nightjar (Caprimulgus tristigma) activity in a seasonal, subtropical habitat
TLDR
It is revealed that caprimulgid activity can be significantly influenced by temperature as well as ambient light, with markedly reduced activity levels on dark nights.
Does the New Zealand rockwren (Xenicus gilviventris) hibernate?
TLDR
The New Zealand rockwren lives permanently at high altitudes on South Island, faces low temperatures and deep snow falls in winter, feeds on insects, goes into torpor, and may tolerate winter by hibernation.
Free-ranging common nighthawks use torpor
...
...

References

SHOWING 1-10 OF 36 REFERENCES
Seasonal Use of Torpor by Free‐Ranging Australian Owlet‐Nightjars (Aegotheles cristatus)
TLDR
The results show that even though Australia is typically thought of as a warm continent, at least some of the avifauna use torpor as a regular means of saving energy.
Daily Torpor in a Free-ranging Goatsucker, the Common Poorwill (Phalaenoptilus nuttallii)
  • R. Brigham
  • Environmental Science
    Physiological Zoology
  • 1992
TLDR
Using temperature-sensitive radio transmitters, the skin temperature of free-ranging birds under natural conditions is measured to test three hypotheses about the use of torpor by poorwills and shows that adult poorwill of both sexes enter torpor regularly in April, May, and September, but not during the breeding season.
Reproduction constrains the use of daily torpor by free-ranging common poorwills (Phalaenoptilus nuttallii) (Aves: Caprimulgidae)
TLDR
It is concluded that reproduction constrains the use of torpor by adult birds, but why non-incubating and non-breeding birds did not enter remains unclear.
NOCTURNAL HETEROTHERMY AND TORPOR IN THE MALACHITE SUNBIRD (NECTARINIA FAMOSA)
TLDR
This study of thermoregulation of Malachite Sunbirds showed that they have circadian fluctuations in Tb and VO2, as in most birds, and plasticity in TB shows that daily variations in T b of homeotherms are biologically important.
Do free-ranging common nighthawks enter torpor?
TLDR
Observations support the idea that nighthawks are not physiologically adapted to enter torpor as a means of energy conservation, and suggest that they should not be used by free-ranging individuals under natural conditions.
EVIDENCE THAT FREE-RANGING COMMON NIGHTHAWKS MAY ENTER TORPOR
TLDR
It is thought it likely that at least under some conditions, nighthawks can allow their body temperatures to fall below normal levels, and Firman et al. (1993) concluded that it was highly unlikely they did so under natural conditions.
Weather Patterns and Daily Torpor in Free­ ranging Animals
TLDR
It appears that inclement weather conditions not only increase thermoregulatory costs, but more importantly, prevent successful foraging in both free-ranging tawny frogmouths and sugar gliders.
Evidence for the use of torpor by incubating and brooding common poorwills Phalaenoptilus nuttallii
TLDR
The origin of long-term cohort differences in the distribution of Greater Flamingos Phoenicopterus ruber roseus in winter and the evolution of dispersal using theoretical models and empirical tests using birds and mammals are studied.
Responses to Temperature by the Spotted Nightjar (Eurostopodus guttatus)
TLDR
Caprimulgid birds have proved to be intriguing subjects for physiological research and several, the Poor-will, Common Nighthawk, and Lesser Nighthawks, have been found to excel in their resistance to frost.
Energetics, thermoregulation and nocturnal hypothermia in Australian Silvereyes
TLDR
The ability of Silvereyes to reduce daily energy expenditure by employing nocturnal hypothermia may be one reason why this species and its relatives are able to occupy a wide variety of habitats and climates.
...
...