A review of literature reveals that published accounts of parental carrying among waterfowl are numerous and of diverse origins. Parental carrying on the back while swimming has been reliably seen in three species of swans, two sheldgeese, and at least seven species of ducks. Parental carrying of young in flight has also been reported for at least 16 species representing seven of the generally recognized waterfowl tribes. The majority of such accounts have involved carrying the young in the bill, a possibility that is somewhat substantiated by reliable observations of egg or eggshell carrying by females of several species. In addition, at least those species that regularly carry the young on the back while swimming may be preadapted to similar carrying of them while in flight. It is suggested that occasional parental carrying by either or both techniques is sufficiently probable as to warrant additional consideration and attention.
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