[obol] Gadwall Courtship and Rivalry in November

[Steve McDonald]

     At Delta Ponds in Eugene today, some normally sedate and quiet
Gadwalls were putting on quite a show.  One drake was defending his
relationship with a female and two other drakes were giving him a hard
time.  They were making chirping whistles and nasal eeping calls.  They
reared up and reached down to touch their chests with their bills, then
spun one-quarter turn.  This is exactly the same routine, including
nearly identical calls, that Green-winged Teal do in the Spring.
Someone has reported seeing our guest Falcated Duck doing this behavior
near Gadwalls and Am. Wigeons. Drake #1 often charged his rivals, in
Mallard-like fashion and they sometimes dove underwater.  After this
subsided, drake #1 and the female swam rapidly in a straight line, a few
feet apart and bobbed their heads in unison, reminiscent of Western
Grebes.  I've never seen any of these activities by Gadwalls before.  It
makes you realize how many similarities the Anas Genus species have,
beneath their very different plumage.  Maybe the unusually bright
sunlight this week has tricked them into thinking it's Spring?  

     I was able to get this all on video, including a Pied-billed Grebe
that caught a large fish.  It was pursued by another grebe and they
chased around quite a while, above and below the surface, before it was
able to choke the fish down.  There are now dozens of these grebes at
Delta Ponds, more than I've seen before.

     Regarding the Am. Wigeon I described previously, I didn't state
that it was a hybrid, but only implied that as a possibility.  I
indicated that it had a golden crown, like that of a Eurasian Wigeon and
left the conclusion open.  It also had some subdued Am. Wigeon colors,
which could be due to the winter plumage not being fully developed yet.
There is also a possibility that 2nd-generation hybrids between these
two species might occur. If a drake was 3/4 American and 1/4 Eurasian
Wigeon, just a few plumage variations from a 100% American might exist.
Whether these two species are close enough to produce fertile hybrids, I
don't know, but my guess is, that they can.

Steve McDonald