This male Bay-breasted warbler, in fine breeding plumage, was migrating through our area last spring. Given the amount of red in his cap, I believe he is a mature bird. Their population is very dependant on the caterpillars of the spruce budworm and other insect infestations and their numbers rise and fall accordingly. They are a little easier to photograph than other warblers as they move about the branches and show themselves a bit more readily.