Biometrics, growth and sex ratios amongst irish dippers cinclus cinclus hibernicus

Abstract

Biometrie data of Irish Dippers were investigated over two years. Wing length, tarsus length and weight were measured from fully grown and nestling birds across a number of sites in southern Ireland. Fully grown birds were found to be sexually dimorphic for wing length, tarsus length and weight. The degree of sexual dimorphism was less than expected, females being larger than reported from most other studies. Weight varied little between seasons, and the annual pattern of weight change was less than that shown for other studies. Nestling growth rate was similar to that of Welsh Dippers. These results are discussed in the context of the ecological niche of the Irish Dipper. © 1992 Taylor & Francis Group, LLC.