Their breeding habitat is mature forests, especially conifers, in Canada, Alaska and the northeastern and western United States. They are permanent residents through much of their range; many northern birds migrate farther south to the United States. Brown creeper has occurred as a vagrant to Bermuda and Central America's mountains in Guatemala, Honduras and the northern cordillera of El Salvador. As a migratory species with a northern range, this species is a conceivable vagrant to western Europe. However, it is intermediate in its characteristics between common treecreeper and short-toed treecreeper, and has sometimes in the past been considered a subspecies of the former, although its closest relative seems to be the latter (Tietze et al. , 2006). Since the two European treecreepers are themselves among the most difficult species on that continent to distinguish from each other, a brown creeper would probably not even be suspected, other than on a treeless western island, and would be difficult to verify even then.