The Gray-headed Chickadee has almost been unnoticed - that is until recently. It is the northernmost chickadee on the continent since it lives at the northern edge of the treeline in Arctic Alaska and northwestern Canada. It survives the dark, ice cold season to mate in the greener season. Perhaps it is not the only bird, but it is the first that I have heard of which does not migrate.
Alaska is home to four species of chickadees: Black-capped Chickadee; Boreal Chickadee; Chestnut-backed Chickadee; and, of course, the Gray-headed Chickadee. The range of the Chestnut-Backed Chickadee is only on the coastline. With the others, the Boreal and the Black-capped Chickadees partly extend in the Gray-headed Chickadees area. They are occasionally even mistaken because they appear so much alike - if you do not look carefully.
In some bird books, you will sometimes see the Gray-headed Chickadee referred to as the Siberian Tit. Those books will not have a photo of the chickadee. The Siberian Tit is the Gray-headed Chickadees Eurasian counterpart. These two birds come from a subspecies Poecile cinctus.
It is said by some that the Gray-headed Chickadee traveled from Norway to Eurasia and eastward to Alaska/Canada. The photos/images of the Siberian Tit and the Gray-headed Chickadee look identical. That is one of the reasons why the Gray-headed Chickadee is currently being researched and studied into more.
*I got parts of my information from http://en.wikipedia.org/wiki/Gray-headed_Chickadee