At Theler Wildlife Reserve in Belfair a female Common Mergazer was sitting, and briefly standing, on the sand at the edge of the Union river  panting. I'd have thought the river water  was cooler. Later we reversed our path, to take advantage of the shade that portion of the trail provided, and the Merganzer was gone. To paraphrae Kipling - "Only mad dogs and Englishmen, (and foolhardy birders) go out in the noon day sun".