Mount Greylock is designated as an important bird area (IBA). There are a number of species of birds which breed in the taiga or boreal forests at the higher altitudes of the mountain, which are not normally found breeding in Massachusetts. These species include the blackpoll warbler and Bicknell's thrush. eBird has records of 132 species of birds on Mount Greylock. There is less known about birds visiting the mountain in winter, as the mountain is more difficult to access during this time.