This Dowitcher was molting quite a few feather groups and here you can see some new basic coverts and that wear has taken away some of the barring on its flanks. On the upper sides just at the bend of the wing, you can see there are short bars still visible where a Short-billed Dowitcher would have spotting, another point for Long-billed. The bird was also in the first stages of a wing molt,large bodied, hunched back and had a very long bill, too long for even a female Short-billed.