Endogenous migratory behaviour in a diurnally migrating songbird

Abstract

Migratory restlessness has been studied intensively in bird species that migrate nocturnally. However, such studies are rare for diurnal migrants. For the first time, we used a twin activity recording design to study the migratory restlessness of a diurnal migrant, the Linnet Carduelis cannabina, by distinguishing foraging activity from possible migratory activity. Hand-reared naive Linnets kept under controlled indoor conditions with a constant photoperiod showed significantly increased diurnal activity, body mass and feeding activity during the autumn migratory period of wild conspecifics. Nocturnal activity was absent. These results imply that diurnal short- to medium-distance migratory songbirds possess endogenous control over their migratory behaviour, similar to nocturnal migrants. Compared to long-distance nocturnal migrants, the seasonal increases in body mass of the Linnets were moderate, likely reflecting their shorter migration routes, which are traversed as a series of short flights with plenty of foraging opportunities en route.