This is an adult male northern shoveler. He is in the middle of molting from his eclipse (non-breeding) plumage to his breeding plumage. All those squiggly lines on his breast will change to solid white, the rust color wil increase coverage on his sides. His head will change fully to solid dark feathers with blue/green iridescence. Cool to see so many shovelers at all the different stages of plumage.
Male Northern Shoveler (Anas clypeata)