MORPHOMETRIC SIMILARITY OF MALLARDS AND AMERICAN BLACK DUCKS

Morphometric data were collected from 347 American Black Ducks (Anas r ubripes), and 1466 Mallards (Anas platyrhynchos) taken by hunters in t he Lake St. Clair and Lake Erie regions of southwestern Ontario during autumn 1986 and from 511 American Black Ducks shot throughout the pro vince of New Brunswick during the 1988 and 1989 hunting seasons. Discr iminant function analyses based on eight external morphometric variabl es (wing chord, tarsus length, middle toe length, hind toe length, cul men, head length, naris width, and bill width) did not accurately dist inguish Black Ducks from Mallards. Discriminant function analyses prod uced correct classification rates that, averaged over the four age - s ex classes, were 61% for Mallards and 71% for Black Ducks. The highest classification rates were from the discriminant function analyses of Ontario Black Ducks and New Brunswick Black Ducks that, averaged over the four age-sex classes, were 74% for Ontario Black Ducks and 80% for New Brunswick Black Ducks. Although our morphometric analyses did not incorporate all morphometric characteristics of Black Ducks and Malla rds, they do show that Black Ducks and Mallards collected in eastern C anada are morphometrically very similar.