Date of Award:
5-1-1982
Document Type:
Dissertation
Degree Name:
Doctor of Philosophy (PhD)
Department:
Biology
Department name when degree awarded
Life Sciences:Biology
Committee Chair(s)
James A. Gessaman
Committee
James A. Gessaman
Committee
Raymond T. Sanders
Committee
Keith L. Dixon
Committee
Raghubir P. Sharma
Committee
LeGrande C. Ellis
Abstract
The energetic cost of incubation and bioenergetics of barn owls (Tyto alba) were studied at the Welder Wildlife Foundation in southern Texas, in northern Utah, and in the laboratory at Utah State University. Metabolism data of 5 incubating owls were compared to metabolic rates of 6 non-incubating captive owls (4 of which were the same birds) and found not to be significantly different over temperatures that ranged from 2-30 C. Therefore, barn owls appear to conduct incubation with little energetic strain and this may partially be explained by the ameliorating effects of incubating inside of nestboxes. These results support King's (1973) contention that incubating birds maintain adequate egg temperatures without elevating their metabolic rates. Incubating barn owl metabolic rates at 5, 15, and 25 C (2.64, 2.20, and 1.76 kcal/hr; respectively) compare well with values predicted by Walsberg and King's (1978a) thermal model (2.84, 2.13, and 1.53 kcal/hr) for the respective temperatures, The barn owl egg metabolism pattern closely resembled that pattern exhibited by an altricial species, During 18 food consumption trials (held at 5, 15, and 25 C) daily consumption by 6 barn owls fed on a laboratory diet (Mus musculus) was 116.9, 96.7, and 76.8 g/d, respectively, Daily gross energy intake, existence metabolism, pellet energy, and excretory energy for the mouse diet were 179.0, 140.2, 23.1, and 15.6 kcal/d at 5 C; 148.9; 116.7, 18.6, and 13.6 g/d at 15 C; and 117.7, 91.7, 13.7, and 12.2 kcal/d at 25 C, respectively, Energy assimilation efficiency was not significantly different at any temperature (78.4, 78.3, and 77.6% at 5, 15, and 25 C, respectively). Barn owl evaporative water loss increased as ambient temperature increased, but this heat loss route was not substantial during incubation because birds did not experience high environmental temperatures (i.e., above 35 C) during incubation.
Recommended Citation
Hamilton, Kirk L., "The Energetic Cost of Incubation and Bioenergetics of the Barn Owl" (1982). Biology. 485.
https://digitalcommons.usu.edu/etd_biology/485
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