Figure 1From: Melatonin reduces migratory restlessness in Sylvia warblers during autumnal migrationMean (± sem) plasma melatonin concentrations in blackcaps (left) and garden warblers (right) at 24:00 h, i.e. 4:30 ± 0:30 hrs after the melatonin treatment. The treatment significantly increased plasma melatonin concentration in both species (see text for details). Numbers above columns indicate sample sizes.Back to article page