The Abundance of River Corridor Birds in Relation to Their Habitats: A Modelling Approach

Abundance of territories on 837 500-m sections of river corridor distributed throughout England and Scotland, collected as part of the British Trust for Ornithology Waterways Bird Survey, were analysed in relation to measured habitat characteristics at these sites. The variation in habitat types and the abundance of birds across the range of river sections was analysed using detrended correspondence analysis. The first axis of both ordinations was similar, showing a major trend from upland fast flowing to lowland slow flowing rivers in both cases. The first axis of the habitat characteristics ordination was used as a measure of habitat «type» as an independent variable and the abundance of territories of each species used as dependent variables in series of log-linear regression models with a restricted data set of English and Welsh rivers