La philopatrie hivernale chez les Anatidés

Broadly, philopatry is the behaviour of remaining in, or returning to, an individual’s birthplace. Species that return in consecutive years to the same breeding site or territory exhibit breeding philopatry or site fidelity. Migrating animals also exhibit philopatry to certain important areas on their route : staging areas, stop-overs, molting areas and wintering grounds.
The level of philopatry can have a significant influence on the genetic structure of populations, but only at the stage of the annual cycle when pair formation and gene exchange occur. Because pair formation in birds typically occurs during the breeding season, most studies have focused on breeding-site philopatry. Waterfowl (ducks, swans and geese) are an important exception to this pattern because pair formation often occurs during the winter months. Geese, swans and sea ducks (eiders, long-tailed ducks, goldeneyes… ) show how levels of winter philopatry, while return rates of dabbling ducks and Pochards seems lower. However, the ornithological park of Pont de Gau (Camargue, France) has presented us the case of an hybrid Ferruginous Duck x Pochard that is watched there every winter for 13 years between the end of October and the month of February !
In this paper, based on a synthesis by Gregory J. Robertson and Fred Cooke, we propose you a presentation of winter philopatry in Anatidae and the genetic and ecological benefits of this behaviour.