The common buzzard in lowland UK : relationships between food availability, habitat use and demography

The common buzzard Buteo buteo is found in a wide variety of habitats throughout the palaearctic and may utilise many prey species. In the UK, the prey and habitat preferences of quantitative models of the relationships between habitat, prey and buzzard demography have only been published for upland regions. In this research, data were collected in a 130km2 lowland area in Dorset, UK. Records of prey at the nest confirmed that the rabbit oryctolagus cuniculus constituted the major food of buzzards in the breeding season. Production of young at the nest was also greater when there was a high proportion of rabbit remains in the nest. Therefore, data collection on prey availability was limited to this species. The breeding density of buzzards increased significantly with the relative density of rabbit burrows, but the relationship between burrow density and production of young at the nest was not significant.Using linear regression, it was possible to explain as much of the variability in nest density using habitat variables alone, as it was by including rabbit density and habitat. Areas of mixed woodlands, grasslands and the total boundary length were associated with high buzzard nest densities, and wetland, heathland and suburban areas were avoided. Soil types were also important: poorly drained clay soils tended to have low buzzard breeding densities and loam soils the reverse. There were few significant relationships between nest productivity and habitat, and no indication of any density dependent effect.