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Thermal emissivity of avian eggshells

Björn, Lars Olof LU ; Bengtson, Sven-Axel; Li, Shaoshan; Hecker, Christoph; Saleem, Ullah; Roos, Arne and Nilsson, Annica (2016) In Journal of Thermal Biology 57. p.1-5
Abstract
The hypothesis has been tested that evolution has resulted in lower thermal emissivity of eggs of birds breeding openly in cold climates than of eggs of birds that nest under protective covering or in warmer climates. Directional thermal emissivity has been estimated from directional–hemispherical reflectance spectra. Due to several methodological difficulties the absolute emissivity is not accurately determined, but differences between species are obvious. Mostnotably, small waders of the genus Calidris, breeding in cold climates on the tundra, and in most cases with uniparental nest attendance, have low directional emissivity of their eggshells, about 0.92 when integration is carried out for wavelengths up to 16 μm. Species belonging to... (More)
The hypothesis has been tested that evolution has resulted in lower thermal emissivity of eggs of birds breeding openly in cold climates than of eggs of birds that nest under protective covering or in warmer climates. Directional thermal emissivity has been estimated from directional–hemispherical reflectance spectra. Due to several methodological difficulties the absolute emissivity is not accurately determined, but differences between species are obvious. Mostnotably, small waders of the genus Calidris, breeding in cold climates on the tundra, and in most cases with uniparental nest attendance, have low directional emissivity of their eggshells, about 0.92 when integration is carried out for wavelengths up to 16 μm. Species belonging to Galloanserinae have the highest directional emissivity, about 0.96, of their eggs. No differences due to climate or breeding conditions were found within this group. Eggs of most other birds tested possess intermediate emissivity, but the values for Pica pica and Corvus corone cornix are as low as for Calidris. Large species-dependent differences in spectral reflectance were found at specific wavelengths. For instance, at 4.259 μm the directional–hemispherical reflectance for galliforms range from 0.05 to 0.09, while for Fratercula arctica and Fulmarus glacialis it is about 0.3.The reflection peaks at 6.5 and 11.3 μm due to calcite are differentially attenuated in differents pecies. In conclusion, the hypothesis that evolution has resulted in lower thermal emissivity of bird-eggs being exposed in cold climates is not supported by our results.The emissivity is not clearly related to nesting habits or climate, and it is unlikely that the small differences observed are ecologically important. The spectral differences between eggs that nevertheless exist should be taken into account when using infrared thermometers for estimating the surface temperature of avian eggs.
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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Avian eggs, Birds, Heat dissipation, Egg cooling, Thermal emissivity. Incubation, Seabirds, Thermal radiation, Waders
in
Journal of Thermal Biology
volume
57
pages
6 pages
publisher
Elsevier
external identifiers
  • Scopus:84957957246
ISSN
0306-4565
language
English
LU publication?
yes
id
083e61ca-ed04-48b1-8046-b8aa9f5e5f1c
alternative location
http://dx.doi.org/10.1016/j.jtherbio.2015.11.008
date added to LUP
2016-04-11 11:48:07
date last changed
2016-10-13 05:05:42
@misc{083e61ca-ed04-48b1-8046-b8aa9f5e5f1c,
  abstract     = {The hypothesis has been tested that evolution has resulted in lower thermal emissivity of eggs of birds breeding openly in cold climates than of eggs of birds that nest under protective covering or in warmer climates. Directional thermal emissivity has been estimated from directional–hemispherical reflectance spectra. Due to several methodological difficulties the absolute emissivity is not accurately determined, but differences between species are obvious. Mostnotably, small waders of the genus Calidris, breeding in cold climates on the tundra, and in most cases with uniparental nest attendance, have low directional emissivity of their eggshells, about 0.92 when integration is carried out for wavelengths up to 16 μm. Species belonging to Galloanserinae have the highest directional emissivity, about 0.96, of their eggs. No differences due to climate or breeding conditions were found within this group. Eggs of most other birds tested possess intermediate emissivity, but the values for Pica pica and Corvus corone cornix are as low as for Calidris. Large species-dependent differences in spectral reflectance were found at specific wavelengths. For instance, at 4.259 μm the directional–hemispherical reflectance for galliforms range from 0.05 to 0.09, while for Fratercula arctica and Fulmarus glacialis it is about 0.3.The reflection peaks at 6.5 and 11.3 μm due to calcite are differentially attenuated in differents pecies. In conclusion, the hypothesis that evolution has resulted in lower thermal emissivity of bird-eggs being exposed in cold climates is not supported by our results.The emissivity is not clearly related to nesting habits or climate, and it is unlikely that the small differences observed are ecologically important. The spectral differences between eggs that nevertheless exist should be taken into account when using infrared thermometers for estimating the surface temperature of avian eggs.<br/>},
  author       = {Björn, Lars Olof and Bengtson, Sven-Axel and Li, Shaoshan and Hecker, Christoph and Saleem, Ullah and Roos, Arne and Nilsson, Annica},
  issn         = {0306-4565},
  keyword      = {Avian eggs, Birds, Heat dissipation, Egg cooling, Thermal emissivity. Incubation, Seabirds, Thermal radiation, Waders},
  language     = {eng},
  pages        = {1--5},
  publisher    = {ARRAY(0xaf237f8)},
  series       = {Journal of Thermal Biology},
  title        = {Thermal emissivity of avian eggshells},
  volume       = {57},
  year         = {2016},
}