Two independent approaches to assessing the constancy of evaporative water loss for birds under varying evaporative conditions

We examine here the effects on evaporative water loss (EWL), at and below thermoneutrality, of perturbing the evaporative environment for the red-capped parrot (Purpureicephalus spurius) by modifying the ambient relative humidity or the diffusive properties of the ambient environment using a helium-...

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Main Authors: Gilson, Lauren Noelle, Cooper, Christine, Withers, Philip Carew, Gagnon, Monique
Format: Journal Article
Published: Elsevier 2021
Online Access:http://purl.org/au-research/grants/arc/DP160103627
http://hdl.handle.net/20.500.11937/84707
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author Gilson, Lauren Noelle
Cooper, Christine
Withers, Philip Carew
Gagnon, Monique
author_facet Gilson, Lauren Noelle
Cooper, Christine
Withers, Philip Carew
Gagnon, Monique
author_sort Gilson, Lauren Noelle
building Curtin Institutional Repository
collection Online Access
description We examine here the effects on evaporative water loss (EWL), at and below thermoneutrality, of perturbing the evaporative environment for the red-capped parrot (Purpureicephalus spurius) by modifying the ambient relative humidity or the diffusive properties of the ambient environment using a helium-oxygen mix (helox). We found that evaporative water loss did not change with relative humidity at an ambient temperature of 30°C, but there was a negative relationship for evaporative water loss with relative humidity at 20 and 25°C. The EWL per water vapour pressure deficit between the bird and its ambient environment was not constant with relative humidity, as would be expected for a physical effect (slope = 0); rather there was a significant positive relationship with relative humidity at ambient temperatures of 25 and 30°C. Consequently, we conclude that the red-capped parrot can physiologically control its EWL over a range of relative humidities. For the first time for a bird species, we also confirmed EWL control using a second methodology to perturb the evaporative environment, and demonstrated that a more diffusive helox atmosphere has no effect on EWL of live birds, but EWL was higher for dead birds in helox compared to air. Our results for EWL and other physiological variables for red-capped parrots are consistent with the hypothesis that EWL is under physiological control.
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spelling curtin-20.500.11937-847072022-08-12T05:19:05Z Two independent approaches to assessing the constancy of evaporative water loss for birds under varying evaporative conditions Gilson, Lauren Noelle Cooper, Christine Withers, Philip Carew Gagnon, Monique We examine here the effects on evaporative water loss (EWL), at and below thermoneutrality, of perturbing the evaporative environment for the red-capped parrot (Purpureicephalus spurius) by modifying the ambient relative humidity or the diffusive properties of the ambient environment using a helium-oxygen mix (helox). We found that evaporative water loss did not change with relative humidity at an ambient temperature of 30°C, but there was a negative relationship for evaporative water loss with relative humidity at 20 and 25°C. The EWL per water vapour pressure deficit between the bird and its ambient environment was not constant with relative humidity, as would be expected for a physical effect (slope = 0); rather there was a significant positive relationship with relative humidity at ambient temperatures of 25 and 30°C. Consequently, we conclude that the red-capped parrot can physiologically control its EWL over a range of relative humidities. For the first time for a bird species, we also confirmed EWL control using a second methodology to perturb the evaporative environment, and demonstrated that a more diffusive helox atmosphere has no effect on EWL of live birds, but EWL was higher for dead birds in helox compared to air. Our results for EWL and other physiological variables for red-capped parrots are consistent with the hypothesis that EWL is under physiological control. 2021 Journal Article http://hdl.handle.net/20.500.11937/84707 10.1016/j.cbpa.2021.111041 http://purl.org/au-research/grants/arc/DP160103627 http://creativecommons.org/licenses/by-nc-nd/4.0/ Elsevier fulltext
spellingShingle Gilson, Lauren Noelle
Cooper, Christine
Withers, Philip Carew
Gagnon, Monique
Two independent approaches to assessing the constancy of evaporative water loss for birds under varying evaporative conditions
title Two independent approaches to assessing the constancy of evaporative water loss for birds under varying evaporative conditions
title_full Two independent approaches to assessing the constancy of evaporative water loss for birds under varying evaporative conditions
title_fullStr Two independent approaches to assessing the constancy of evaporative water loss for birds under varying evaporative conditions
title_full_unstemmed Two independent approaches to assessing the constancy of evaporative water loss for birds under varying evaporative conditions
title_short Two independent approaches to assessing the constancy of evaporative water loss for birds under varying evaporative conditions
title_sort two independent approaches to assessing the constancy of evaporative water loss for birds under varying evaporative conditions
url http://purl.org/au-research/grants/arc/DP160103627
http://hdl.handle.net/20.500.11937/84707