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Ecology and Energetics of Sandlerlings Migrating to Four Latitudes
Author(s) -
Castro Gonzalo,
Myers J. P.,
Ricklefs R. E.
Publication year - 1992
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1940161
Subject(s) - panama , energetics , ecology , basal metabolic rate , daylight , energy expenditure , latitude , environmental science , calidris , geography , biology , zoology , habitat , biochemistry , physics , geodesy , optics , endocrinology
We examined ecophysiological responses of Sanderlings (Calidris alba) to their nonbreeding environments in New Jersey (USA), Texas (USA), Punta Chame (Panama), and Puerto Viejo (Peru). Daily energy expenditure (DEE; measured using doubly labeled water) was strongly influenced by the thermal environment, being higher at colder locations, and equivalent to 4.2 times the basal metabolic rate of New Jersey, 2.8 in Texas, 2.1 in Panama, and 2.7 in Peru (200, 135, 100, and 129 KJ/d; n = 10, 5, 10, and 16, respectively. Time budgets varied among locations, but in all cases feeding and roosting accounted for °90% of daylight hours. Feeding times were 55% in New Jersey, 90% in Texas, 40% in Panama, and 45% in Peru, suggesting that Sanderlings required more time to satisfy their food requirements in Texas than in the other locations. Total body mass and body fat increased linearly with decreasing long—term mean January air temperature but, because of the synchronous increase in energy expenditure, predicted survival times during food deprivation increased only slightly. Individual Sanderlings experience different living conditions throughout their non—breeding distribution, with DEE and nutritional reserves being determined primarily by temperature. Time budgets vary accordingly to accommodate these demands.