Does migration promote or restrict circumpolar breeding ranges of arctic birds?

Aim: Migration has been suggested to promote large breeding ranges among birds because of the greater mobility of migratory compared to non-migratory species, but migration has also been suggested to restrict breeding ranges because of evolutionary constraints imposed by the genetical migration programme. We aim to investigate the association between migration and the breeding ranges of both land birds and pelagic birds breeding in the Arctic region. Location: The Arctic region. Methods: Information on breeding and wintering range and migratory status of bird species breeding in the Artic tundra biome was compiled from the literature. The association between breeding range, migration distance, primary winter habitat and phylogeny was tested using multivariate general linear models (GLM) and pair-wise Mann-Whitney U tests. Phylogenetic effects were tested for using Mantel’s permutation tests. Results: We found different relationships depending on the species’ major winter habitat. Among birds that are pelagic during winter, long-distance migrants have the largest breeding ranges, while among terrestrial birds, residents and short-distance migrants have the largest breeding ranges. Breeding ranges of coastal birds of all migratory distance classes are comparatively restricted. Main Conclusions: As a new explanation for this pattern we suggest that the possibility to colonize large winter ranges is a key factor for the subsequent expansion of breeding ranges in the Arctic bird communities and possibly also in bird communities of other regions of the world. Because of the reversal in relative extent of continents and oceans between the hemispheres, longitudinally wide winter ranges are more likely for long-distance than short-distance migrants among pelagic birds, while the reverse holds true for birds that use terrestrial winter habitats. For coastal birds both continents and oceans form barriers restricting colonisation of extensive winter quarters and consequently also of extensive breeding ranges regardless of the distance to the winter quarters