Daytime movements of nocturnal migrants at stopover between two nearby capture sites

Abstract

The scale of movements that passerine migrants perform during stopover is an important parameter of avian stopover ecology and behaviour. The scale of daytime movements has been estimated by captures of losing track of individuals that perform the longest movements. To estimate the upper limit of such daytime movements, I analysed recaptures of six nocturnal passerine migrant species between two trapping sites on the Courish Spit in the Eastern Baltic located 10.7 km apart. The proportion of birds that covered this distance during the daytime varied between species and seasons, but was generally very low, varying between 0 and 0.140%. Ten kilometres appears to be at the very upper limit of the distance covered by nocturnal migrants during their daytime movements, with the bulk of birds remaining within a much smaller area. No evidence supports the view that, in the daytime, nocturnal migrants significantly prefer to move in the migratory direction, even on the Courish Spit which runs along the migratory route of most passerine migrants in the area.