This morning we are watching a female Wood Duck in our nestcam box;
she was there by about 6:15 a.m., and did not spend the night, so
incubation has not yet begun. She has now been in the box for about
an hour. During this time, a second female Wood Duck entered the box
and plopped down on top of the first one. Wood Duck #1 proceeded to
nibble constantly around the head and crest of the intruder for the
full ten minutes the intruder was in the box. To our eyes, this
nibbling looks gentle and affectionate, but we believe that it is an
aggressive warning to the intruder, though no further action was
taken. We believe the intruder laid an egg during the short time it
was in the box, so the original Wood Duck will be a foster mother for
at least one baby, assuming she carries the incubation to completion.

I have continued emptying out the nest box of Starling nest materials
each day, because a pair of deluded Starlings thinks they are going
to win their battle with me and the Wood Duck. When I cleaned the
box yesterday, there were seven eggs.

By the way, yesterday a Hooded Merganser female entered the box in
late morning and remained for about five minutes. It is possible
that she laid an egg. Wood Ducks and Hooded Mergansers are so
intertwined in their biology and habits that their eggs are close in
size and incubation times are the same. Twice we have observed
fledging of babies of both species in the same box, and the mother
doesn't seem to realize that she will be the guardian for another
species' young. But it all works out.

Lee Rentz
Shelton, WA
lee at leerentz.com
http://leerentz.wordpress.com