Figure 1.

Mean (± s.e.m.) daily minimum heart rate per day throughout the annual cycle of six wild barnacle geese. The year is split into five distinct seasons: winter, spring migration, breeding, flight-feather moult and autumn migration. Mean minimum heart rate is significantly higher during flight-feather moult than other times of the annual cycle. See the electronic supplementary material, figure S1 for individual heart rate traces per bird.