Cliff swallows have a dark head, cream color above their bill, and dull red on their face and neck. They are very social and nest in large colonies, usually on a cliff, but also will nest under the eaves of tall building. The closest cliff swallows that I know about nest under the eaves of a school in Ulster County.
*** News flash! On our May bird census on 5/16/15, we found cliff swallows nesting in the town of Washington in Dutchess County. ***
If you were a cliff swallow along this trail, where would you hide your eggs? Not sure if it's snow friendly...