The aggregative response of common murres and Atlantic puffins to schools of capelin

Studies in Avian Biology
By:
Edited by: Spencer G. Sealy

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Abstract

I studied the aggregative responses of Common Murres and Atlantic Puffins to schools of capelin during three summers (1982-1984) at Witless Bay, Newfoundland, by conducting hydroacoustic surveys for capelin in synchrony with seabird censuses. Murres and puffins foraged offshore prior to the arrival inshore of spawning schools of capelin. Both species were abundant during peak periods of capelin abundance from late June to late July, but only puffins continued to forage inshore after capelin schools dispersed in August. On individual surveys, murre and puffin flocks were significantly correlated with capelin schools at fine and coarse spatial scales. Aggregation intensity and spatial correlations peaked at measurement intervals of 2-6 km. At that scale, murres and puffins exhibited sigmoidal (Type III) aggregative responses to capelin schools. Inflection points (thresholds) in sigmoidal aggregative response curves occurred at higher densities of capelin for murres than for puffins and foraging thresholds for both species varied daily with overall capelin abundance in Witless Bay. Murres probably foraged on denser schools of capelin than puffins because of their larger body size and associated higher food demands. The implications of differing foraging thresholds for population ecology of alcids are discussed.

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Publication type Book chapter
Publication Subtype Book Chapter
Title The aggregative response of common murres and Atlantic puffins to schools of capelin
Series title Studies in Avian Biology
ISBN 0935868496
Volume 14
Year Published 1990
Language English
Publisher Cooper Ornithological Society
Contributing office(s) Alaska Science Center
Description 16 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Auks at sea: Proceedings of an International Symposium of the Pacific Seabird Group (Studies in Avian Biology no.14)
First page 36
Last page 51
Conference Title An International Symposium of the Pacific Seabird Group
Conference Location Pacific Grove, CA
Conference Date December 17, 1987
Country Canada
State Newfoundland
Other Geospatial Witless Bay
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