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Foraging energetics of arctic cormorants and the evolution of diving birds
Author(s) -
Grémillet David,
Wanless Sarah,
Carss David N.,
Linton Danielle,
Harris Mike P.,
Speakman John R.,
Le Maho Yvon
Publication year - 2001
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1046/j.1461-0248.2001.00214.x
Subject(s) - energetics , foraging , predation , arctic , ecology , biology , bioenergetics , temperate climate , energy expenditure , thermoregulation , fishery , mitochondrion , microbiology and biotechnology , endocrinology
Efficient body insulation is assumed to have enabled birds and mammals to colonize polar aquatic ecosystems. We challenge this concept by comparing the bioenergetics of cormorants ( Phalacrocorax carbo ) living in temperate and arctic conditions. We show that although these birds have limited insulation, they maintain high body temperature (42.3 °C) when diving in cold water (1–10 °C). Their energy demand at these times is extremely high (up to 60 W kg −1 ). Free‐living cormorants wintering in Greenland (water temperature −1 °C) profoundly alter their foraging activity, thus minimizing time spent in water and the associated high thermoregulatory costs. They then meet their daily food demand within a single intense dive bout (lasting 9 min on average). Their substantial energy requirements are balanced by the highest predatory efficiency so far recorded for aquatic predators. We postulate that similar behavioural patterns allowed early diving birds (Cretaceous) to colonize cold coastal areas before they evolved efficient insulation.