Evolutionary Relationships among the North American Mallards

Abstract

THIS study is the report of an attempt to understand the evolutionary relationships existing within a group of mallardlike ducks native to North America. The group includes the Common Mallard, Anas platyrhynchos platyrhynchos L.; the Black Duck, Anas rubripes Brewster; the Florida Duck, Anas fulvigula fulvigula Ridgway; the Mottled Duck, Anas fulvigitla niiaculosa Sennett; the Mexican Duck, Anas diazi diazi Ridgway; and the New Mexican duck, Anas diazi novimexicana Huber. All but one of these (the Common Mallard) are restricted to North America, and all these American forms possess a sexually nondimorphic plumage. In all other respects they are extremely similar to the Common Mallard, and a study of their relationships to this form was believed possibly to provide an instructive example of speciation.