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Metabolic Patterns of Feeding, Overnight Fasted and Flying Night Migrants during Autumn Migration
Lukas Jenni and Susanne Jenni-Eiermann
Ornis Scandinavica (Scandinavian Journal of Ornithology)
Vol. 23, No. 3, Proceedings of the Symposium Hormones, Physiology and Non-Reproductive Behaviour in Birds, 21-23 August, 1991, Göteborg, Sweden (Jul. - Sep., 1992), pp. 251-259
Stable URL: http://www.jstor.org/stable/3676646
Page Count: 9
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During the migratory season, the metabolism of night migrants has to deal with three main physiological situations and their transitions: (1) feeding during the day for fat deposition, (2) overnight fasting during stop-over and (3) nocturnal flight. Plasma metabolite levels of glucose, uric acid, triglycerides, free fatty acids, glycerol and β-hydroxy-butyrate (β-OHB) were used in Principal Component Analyses to determine independent factors which characterize these physiological situations and allowed the comparison of three species of night migrants: Garden Warbler Sylvia borin, Pied Flycatcher Ficedula hypoleuca and European Robin Erithacus rubecula. During overnight fasting, all three species had a low fat metabolism and protein catabolism. During feeding, birds showed high triglyceride and uric acid levels. During flight, birds were characterized by a high fat metabolism and protein breakdown with the particular feature of having high triglyceride levels. Differences among species during flight suggest that the Garden Warbler showed the most specialized metabolic adaptations to endurance flight relying most strongly on fat and having the highest body fat reserves. The Robin showed the opposite pattern and the pattern of the Pied Flycatcher was intermediate. Birds in transition between the main physiological situations were characterized by a low glucose/β-OHB ratio.
Ornis Scandinavica (Scandinavian Journal of Ornithology) © 1992 Nordic Society Oikos