We describe evidence that Harlequin Duck (Histrionicus histrionicus) broods
accompany their mothers from breeding streams to coastal molting or winter
ing areas. Observations indicated that all surviving female-offspring group
s left breeding areas together. We later sighted some family members at the
coast near each other, suggesting that they had arrived together, then sep
arated. We observed family groups at wintering areas in August and Septembe
r Family groups tended to separate quickly, although some family members ma
intained contact for over five months. To our knowledge the evidence we pro
vide is the first suggesting that female migratory ducks bring their offspr
ing to wintering areas, a pattern similar to geese and swans. This may be f
acilitated by an unusual strategy of wing molt, in which Harlequin Ducks mo
lt after migrating to wintering areas. Due to winter pairing and strong phi
lopatry in Harlequin Ducks, migration of families may contribute to genetic
differentiation among populations.