Dowitcher ID here in CO (as elsewhere) can be difficult, so I wanted to share this excellent presentation by Jon Dunn of identification of dowitchers given earlier this year, as presented on the Los Angeles County CA birding website:
There is a California bias in the photos and some distribution discussion but it applies here in CO. It is not a short presentation, but goes into a good amount of detail, and if we can remember a handful of salient points and the dowitchers are closer than 4 football fields away, we might stand a chance!
David Suddjian
Littleton, CO