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”