Catabolic enzyme activities in the pectoralis muscle of premigratory and migratory juvenile Reed Warblers Acrocephalus scirpaceus (Herm.).

Differences in catabolic capacity in the pectoralis major muscle of premigratory and migratory Reed Warblers were examined. The oxidative capacity was greater in the migratory birds, probably reflecting a "training effect" caused by the increased locomotion activity just prior to migration.Fatty acid oxidation was already high in the premigratory birds, possibly reflecting a saving of carbohydrate for anabolic purposes (feather growth) during the moult. Glycolytic capacity was slightly increased in the migratory birds, suggesting an increased carbohydrate oxidation during migration in spite of the great contribution of fatty acid oxidation.