No evidence that declining Whinchat Saxicola rubetra are currently limited by the availability of apparently suitable breeding habitat within the UK uplands

Many species of long-distance Afro-palearctic migrant birds that breed in Europe are showing severe population declines and there is a need to understand in which parts of the migratory cycle the drivers of decline occur. Building on previous research that suggests that widespread Whinchat Saxicola rubetra declines across the European range are not associated with conditions on African non-breeding grounds, we test the role of habitat availability in the UK upland breeding range as a limiting factor, where Whinchat are widely declining. Across semi-natural grassland, heathland, bog and scrubland, Whinchat territories were characterised by higher Bracken Pteridium aquilinum cover, low density of trees and closer proximity to valley bottoms than paired unoccupied reference locations. Upland valleys may provide sheltered, warmer micro-climates, and wetter habitats in the bottom, that are potentially favourable for Whinchat. Occupancy modelling against these habitat measures at an independent set of sites estimated that 41.1% (95% CI 28.9–56.8%) of apparently suitable habitat was occupied by breeding birds. We conclude that the availability of suitable habitat in the main UK upland range does not currently appear to be limiting Whinchat.