Animals of different phenotype differentially utilise dietary niche- the case of the Great Grey Shrike Lanius excubitor

Abstrakti

We tested the morphological trait utility in Great Grey Shrike Lanius excubitor. The food composition was used as an indicator of phenotype performance advantage in utilising of particular dietary niche. Mounts and accompanying data (measurements and stomach contents) from the Slovak extensive collection, involving adult birds obtained from April to October, were selected for analysis (n = 48). Ordination methods (redundancy analysis) and Generalized Linear Model regression show that the composition of the bird's food was non-random in respect to body characteristics. Tarsus and wing lengths were the most important morphometric predictors and ex- plained 12.7% of overall variance in food data. Smaller birds foraged mainly on Carabidae. Individuals with longer wings and tails more frequently preyed on flying and plant-dwelling insects. We conclude that phenotypic characteristics of an animal at least partially determine its diet.