
We have never seen this bird in our yard before, but yesterday several appeared at the feeders. We looked in our bird books, but couldn't find them. Grandpère said that it may be a Tree Duck. The shape of the head, feet, bill, and body of were similar, but the plumage, bill, and legs and feet of the birds in our yard was so very different in color than the ducks in the picture. We wondered if habitat could have the effect of changing their color that much.

My son said they were definitely Black-bellied Whistling Ducks from Mexico. We went online again and found the ducks, as you see, at another website. The two names seem to be for the same duck, and at the second site we found these words which solved the puzzle:
Juvenile is paler, with grey bill, legs and feet. It has duller plumage than adults, with sooty-brown belly and flanks. It reaches its adult plumage at 8 months of age.
Very young birds have very paler belly, with indistinct transversal bars.
The pictures are from a distance, because I couldn't get closer to the ducks without making them fly away, and my digital camera is not one of the finest. I bought it for its small size and its reasonable price. My regular camera takes much better pictures, but, of course, I have to have the disks developed.
UPDATE: Here's another view. I also posted larger versions of the other pictures.

UPDATE 2: And yet another, though blurred, view of the mystery bird, which I took today:

I think it's a juvenile Black-bellied Whistling Duck. The proof would have been if the bird had whistled for me, but it didn't.
