There are, however, other variations. A migrating bird that looks noticeably different may just be a Hermit Thrush from a different area. The reddish color on the tail extends up onto the rump and is very conspicuous on Hermits from the Northeast. Elsewhere, it may not be so obvious. The eye-ring field mark is tricky.
Hermit Thrushes, however, also have eye-rings, often very noticeable.
To avoid being misled, we need to look at several field marks. Tail color has to be studied carefully, since the Hermit's reddish tinges can be hard to see. Bicknell's is a scarce bird, nesting mainly in Quebec, the Maritimes, New England, and upstate New York. It looks much like a Gray-cheeked, but tends to be warmer brown, often with a chestnut wash on the tail. Top expert birders are still struggling with the separation of Bicknell's and Gray-cheeked Thrushes.