>Can anyone comment on this behaviour, is there known to be recognition by
>adults of the young from prior years? Also, can anyone confirm my thought
>that the males breed and then leave the female, there were no males to be
>seen this weekend.
>
>Eric Greenwood

I can't answer the first question, although it wouldn't be too surprising.
Birds recognize each other as individuals in many situations.

The second question is definitely true, for essentially all temperate-zone
ducks. The males, as soon as they have a female on a nest, desert her and
go off to molt somewhere. In ducks, the young feed themselves and the
female by herself can easily lead them to water and warn them of predators,
so including the male in the parental-care picture wouldn't add much. In
swans and geese, which by virtue of their large size can actually drive off
predators, evolution has led to shared parental care. This doesn't explain
the shared parental care in most tropical ducks, however. Maybe more
significant is the fact that in the migratory temperate-zone species there
has been stronger selection on male ducks to desert the females and get
back to their wintering grounds as quickly as possible (as happens in many
shorebirds, although in shorebirds it's more likely to be the female that
deserts the male).

Dennis Paulson, Director phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416