Factors influencing the abundance of breeding Dippers Cinclus cinclus in the catchment of the River Wye, mid-Wales

The number of breeding Dippers was assessed in relation to environmental features and benthic macro-invertebrates over 220 km of tributaries in or adjacent to the catchment of the Welsh River Wye in 1982. Bivariate regression and multivariate analysis revealed strong correlations between breeding abundance and combinations of variables describing stream-gradient and the relative abundances of larval Trichoptera and nymphal Plecoptera. The results are discussed in relation to aspects of the feeding ecology of breeding Dippers and their nestlings.