Broad‐scale patterns in geographical and habitat distribution of migrant and resident passerines in Britain and Ireland

Abstract

We analysed patterns of breeding habitat use in migrant and resident passerines on a broad geographical scale in Britain. Migrants were less widely distributed than residents and used fewer habitats. Although resident genera that were more widespread used more nesting habitats, this did not hold for migrant genera though it did at the species level. Although migrancy status in Europe has been associated with the use of ‘open’ structural habitat types (e.g. scrubland), evidence from Britain was contradictory. Within lowland woodlands the ratio of migrants to residents and the density of migrants was highest in habitats with large areas of young growth. The highest migrant ratios of all, however, were recorded in mature upland woods, with little or no undergrowth. These upland woods carried the lowest densities of residents. Regression models accounting for variation in the migrant ratios and densities in woodland habitats varied according to the geographical scale on which they were constructed. The extent of young growth was a strong predictor of migrant ratios and densities in south‐east England but not for woods in the north and west. Resident densities in northern and western woods were inversely related to altitude. Copyright © 1992, Wiley Blackwell. All rights reserved