In response to a posting by Michael Price about swan head staining,
Trumpeters breed in boreal forest lakes in s. Alaska and n. British
Columbia, which I imagine have very different chemical composition than the
tundra lakes on which Tundras breed. I assume they get their staining when
they're foraging for water plants with heads in the bottom ooze in fresh
water on their breeding grounds. Then they get their bill and head stained
by mud in the fields around here; fortunately, it washes off.

I've noticed it in other winters, but it was really striking this weekend.
You do see Trumpeters with white heads, and I suppose Tundras with stained
heads, but I can't recall about the latter.

I just looked at the swans in the Audubon Master Guide for probably the
first time, and the "Trumpeter" in there is a Tundra! Amazing. No wonder
there are so many problems for beginning birders.

I also recently discovered a pretty good flight field mark for adults. In
Trumpeter, the line marking the lower edge of the bill as it extends toward
the eye is pretty much at a diagonal. In Tundra, it has a strong vertical
component, and this difference can be seen at a surprising distance.

Finally, it's interesting that Snow Geese also have stained heads, I assume
the same iron in the water that stains the Trumpeters. Not all of them
have this, but it looked to me that essentially all the birds in the
Stanwood flock did so. Wonder if you could pick out a Ross' Goose by its
white head (they don't seem to be stained)? We also have small numbers of
Snow Geese from the Canadian-breeding populations in this region, and
perhaps they're not stained.

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