Data from: Geographical and habitat factors affected migratory waterbirds along rivers in the Palearctic

Rivers are important habitats for many waterbird species, offering crucial resources such as feeding and resting areas during migration. The migratory patterns of this group of birds are influenced by a variety of factors, including geographical location, habitat availability, and environmental conditions. Despite the huge ecological importance of rivers, there are few studies on how riverine environments support migratory bird populations across a broad geographical scale. This study shows waterbird populations during migration along 14 big and unregulated rivers spanning Europe and Asia, documenting a total of 63,383 birds across 112 species. Analysis revealed significant associations between species richness and bird abundance and geographical proximity, with neighboring rivers displaying greater similarity in species composition and density. The presence of sand banks and islands emerged as critical factors influencing species richness and bird abundance, while forested river segments negatively impacted species richness compared to open landscapes like fields. Unexpectedly, river width showed no significant effect on avian assemblages.

The study was conducted during the autumn migration of birds. Through a combination of ecological assessments and statistical analyses, we identified the primary drivers influencing migratory bird distribution, species richness, and abundance.