Avian distribution patterns in fragmented wooded landscape (North Humberside, UK): the role of between-patch and within-patch structure

The bird populations of sixteen small isolated woodlands were enumerated and their patterns of abundance and species richness were analysed in relation to both between-patch (patch area, isolation, shape) and within-patch (habitat physiognomy) structure. The distribution of birds was found to be primarily related to landscape structure represented by an underlying gradient of habitat fragmentation. Three main patterns of avian patch occupancy were identified: woodland species, edge species and ubiquitous species. These patterns were explained due to the effects of landscape structure acting on individual populations consistent with metapopulation models. Numbers of woodland species declined over the fragmentation gradient whilst numbers of edge species increased. Patterns of avian distribution at the regional landscape were related to those at the broader national scale and results support the hypothesis that British mainland woodland bird distribution could be explained due to the effects of fragmentation