I've mentioned this before, but once you photograph a bird species it becomes much easier to ID that species in the field. Merely looking at photos from a book, or online doesn't seem to stay into memory with the necessary tenacity, while shooting it, and then processing the image will almost certainly commit the sighting into memory. I wouldn't have necessarily been able to identify a Short-billed dowitcher on sight because it is new to me, having only previously seen a couple of Long-billed dowitchers last year. So, I may have guessed dowitcher, or not, or should I say, or knot ... red knot. As for Vesper sparrow, the pink/beige bill and legs and the eye-ring is what caught my attention. The mottling of the bird's back was also unlike a song sparrow. At first I though the sparrow on the beach was a song sparrow but then I noted the pale yellow lore. A young bird would have a less intense yellow and would show some pink around the bill as displayed by the sparrow in my photo.
The site was Ed Broadbent Park in Oshawa.