Individual Problems
Although “pattern recognition” simplifies the problem of identification for the waterfowler, there are still several complications to be considered. Of these, the most troublesome by far is the matter of moults. The adult drakes of most species of ducks, very soon after the hens begin to incubate eggs, moult the bright body-feathers of their breeding dress and assume an “eclipse” plumage which resembles the year-round coloration of the female. This dull plumage, serving as a protective factor during the wing-moult which follows, is retained until the new flight feathers are fully developed. By September a second body-moult is under way by which these old drakes assume the bright courting plumage of late fall and winter. During the same period, the young males of the year, whose juvenile plumage likewise resembles the female dress, are also assuming the adult plumage. Following December 1 most difficulties of identification by reason of the moult are resolved, but in early fall the hunter may be puzzled by some of the transition plumages noted on birds in his bag. Identification during this period may appear extremely difficult, but it is well to remember that wing patterns remain virtually unchanged regardless of stage of the moult.
The remaining problems of identification require only brief mention for they appear but rarely. In the first place, this booklet includes all species of ducks and geese which occur in numbers in any part of the Central Flyway, but omits others which may be occasional visitors. Second, hybrids are rather frequent among waterfowl, and some are extremely puzzling. In such special cases as these your local wildlife manager or biologist may be able to help.
The following publications contain further information for the hunter interested in additional facts of natural history, distribution and description:
Kortright, “Ducks, Geese and Swans of North America” Peterson, “A Field Guide to the Birds” Pough, “Audubon Water Bird Guide”