Earlier this morning I found 2 Swainson's and 1 Gray-Cheeked/Bicknell's Thrush 
at Red Rocks. I am leaving Gray-Cheek as a possibility, as the darker grayish-
brown plumage on the upperparts seemed consistent with the tail, gray 
around eyes and cheeks and no visible eye ring. The plumage appeared a 
shade darker than the Swainsons it was with. 

All these birds were in the section to the right after entering the park. As you 
walk in this path, the area to the left with its relatively thick undergrowth and 
wet area, is where I found these birds.