In Alaska, Iliaca inhabits alder and willow thickets in spruce forest, often in white spruce (Austin 1968). Unalascensis occurs from beaches to timberline, preferring willow and blackberry thickets, and lush and brushy riparian vegetation (Linsdale 1928, Williamson and Peyton 1962, Austin 1968).
Austin, Jr., O. L. 1968. Fox Sparrow (various subspecies). Pp. 1392-1395, 1414-1434 in Life histories of North American cardinals, grosbeaks, buntings, towhees, finches, sparrows, and their allies (O. L. Austin, Jr. ed.) U. S. Nat. Mus. Bull. 237. Pt. 3.
￼￼Linsdale, J. M. 1928. Variation in the Fox Sparrow (Passerella iliaca) with reference to natural history and osteology. University of California Publ. Zool. 30:251-392.
Williamson, F. S. L. and L. J. Peyton. 1962. Faunal Relationships of birds in the Iliamna Lake Area, Alaska. Biological Papers of the University of Alaska Number 5, Anchorage.￼