Correlates of population density and body weight of raptors in the family Accipitridae: a comparative study


All correspondence to present address: Department of Animal Behaviour, University of Bielefeld, Postfach 100131, 33501 Bielefeld, Germany. E-mail:


This study is the first attempt to use both independent contrasts and cross-genera correlation for the family Accipitridae to see if population density and body weight are associated with other ecological or morphological variables. Using literature data on nine variables for 189 species of 35 genera, significant associations between contrasts in population density and reproductive rate and hunting method were found. Cross-genera correlation results differed because all morphological variables were negatively correlated with population density while none of these correlations was significant using independent contrasts. Contrasts in body weight were positively correlated with mean prey weight and negatively with range size. Overall, reproductive rate had the highest correlations with population density.