Discrimination of Mallard Strains on the Basis of Morphology

Abstract

We detected differences in morphology among strains of wild, urban, and game-farm mallards (Anas platyrhynchos) from the Mississippi Flyway. A 3-strain discriminant function analysis (DFA) model (to discriminate 3 strains) and a 2-strain DFA model (to discriminate wild mallards from urban mallards, the strain that most closely resembled wild mallards) were developed to predict group memberships on the basis of 6 morphological variables. We used a stepwise procedure to develop a reduced 2-strain model that discriminated wild mallards on the basis of 3 variables : tarsus width, total tarsus length, and culmen length. Accuracy of the models ranged from 87.3 to 96.4% for males and 95.7 to 100% for females. Canonical coefficients are provided for use with unstandardized measurements to classify mallards