Seasonal variations of serum glucose levels in a migratory songbird, Sylvia borin

Abstract

1. 1. Ten juvenile Garden Warbler Sylvia borin were maintained in controlled laboratory conditions and their blood sugar concentrations were determined regularly. 2. 2. The concentrations of blood glucose were higher during the migratory periods both in autumn and in spring. 3. 3. The study reveals a seasonal rhythm in the blood glucose levels in a migratory songbird. 4. 4. The laboratory data are supported by data of wild birds trapped at different times.