The development of homeothermy in the American goldfinch

Mayer, Larry; Lustick, Sheldon; Battersby, Brian

doi:10.1016/0300-9629(82)90240-7

“…A number of studies measured metabolic rate (O2 consumption or CO2 production) of nestlings over a range of temperatures to investigate the development of endothermy. From the figures presented in those studies, the lower critical limit of the thermoneutral zone seems to typically fall between 30-35°C (Dawson & Evans, 1957, 1960Dyer, 1968;Mayer et al, 1982;Nager & Wiersma, 1996;Sirsat et al, 2016), which is consistent with the lower critical limit we identified for superb fairy-wren nestlings. Only one study of developing cattle egret (Bubulcus ibis) nestlings studied higher temperatures (up to 45°C) (Hudson et al 1974), which suggested metabolic rate to be minimal from 34°C to 40°C, relatively similar to superb fairy-wren nestlings despite the difference in the body size and ecology of the species.…”

Section: High and Narrow Thermoneutral Zonesupporting

confidence: 78%

Thermoregulatory strategies of songbird nestlings reveal limited capacity for cooling and high risk of dehydration

Diehl

¹

,

Alton

²

,

White

³

2023

Preprint

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Developing young are particularly sensitive to environmental challenges, often with life-long consequences, but the risks of climate warming during this period are not well understood. To quantify the physiological effects of increasing temperatures for developing endotherms, we measured metabolic rate, water loss, and heat dissipation behaviours between 25-45°C in nestlings of a free-living songbird. The thermoneutral zone ranged from 33.1–42.3°C – higher and narrower than adults – and metabolic rate increased sharply above and below this range. Water loss was constant below 33.5°C, above which it increased sharply, when nestlings also drooped their wings to lose heat. Despite nestlings initiating panting (p50) around 40°C, water loss was never sufficient to dissipate metabolically produced heat, indicating poor cooling capabilities. Our data show that while developing young appear relatively tolerant to higher temperatures, they are at a high risk of dehydration and hyperthermia, with limited ability to mitigate these risks of increasing temperatures.

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“…A number of studies measured metabolic rate (O2 consumption or CO2 production) of nestlings over a range of temperatures to investigate the development of endothermy. From the figures presented in those studies, the lower critical limit of the thermoneutral zone seems to typically fall between 30-35°C (Dawson & Evans, 1957, 1960Dyer, 1968;Mayer et al, 1982;Nager & Wiersma, 1996;Sirsat et al, 2016), which is consistent with the lower critical limit we identified for superb fairy-wren nestlings. Only one study of developing cattle egret (Bubulcus ibis) nestlings studied higher temperatures (up to 45°C) (Hudson et al 1974), which suggested metabolic rate to be minimal from 34°C to 40°C, relatively similar to superb fairy-wren nestlings despite the difference in the body size and ecology of the species.…”

Section: High and Narrow Thermoneutral Zonesupporting

confidence: 78%

Thermoregulatory strategies of songbird nestlings reveal limited capacity for cooling and high risk of dehydration

Diehl

¹

,

Alton

²

,

White

³

2023

Preprint

0

View full text Add to dashboard Cite

Developing young are particularly sensitive to environmental challenges, often with life-long consequences, but the risks of climate warming during this period are not well understood. To quantify the physiological effects of increasing temperatures for developing endotherms, we measured metabolic rate, water loss, and heat dissipation behaviours between 25-45°C in nestlings of a free-living songbird. The thermoneutral zone ranged from 33.1–42.3°C – higher and narrower than adults – and metabolic rate increased sharply above and below this range. Water loss was constant below 33.5°C, above which it increased sharply, when nestlings also drooped their wings to lose heat. Despite nestlings initiating panting (p50) around 40°C, water loss was never sufficient to dissipate metabolically produced heat, indicating poor cooling capabilities. Our data show that while developing young appear relatively tolerant to higher temperatures, they are at a high risk of dehydration and hyperthermia, with limited ability to mitigate these risks of increasing temperatures.

show abstract

“…); 54, Pettit and Whittow (1983); 55, Langham (1983); 56, Pettit et al (1981); 57, Dorward (1963); 58, Ricklefs and White (1981); 59, Klaassen and Zwaan (in Drent and Klaassen 1989); 60, Klaassen et al (1989c); 61, Konarzewski et al (in prep. ); 62, Drent (1965); 63, Bech et al (1987); 64, Eppley (1984); 65, Vleck et al (1979); 66, Ar et al (1987); 67, Bucher (1983); 68, Carey et al (1982); 69, Mayer et al (1982); 70, Williams and Prints (1986). Table 2.…”

Section: Resultsmentioning

confidence: 99%