Xen- (prefix): Foreign or other. As in: 1  Xenoantigen -- An antigen that is found in more than one species.  Xenograft -- A surgical graft of tissue from one species to an unlike species, genus or family.
Diet. Snow Geese feed almost exclusively on plant material. During the breeding season, they eat many seeds, leaves, and roots of aquatic vegetation. The very young birds feed on invertebrates. Berries become more important in the fall. In winter, waste grain from agricultural fields has become a primary food source.
In winter months, Snow Geese form highly gregarious flocks that may number into the thousands. The bill of the Snow Goose has a distinctive grin patch along its side. The Ross s Goose looks like a Snow Goose, but is smaller, and its bill lacks the grin patch. The two grayish birds shown here are young Snow Geese. The dark bird shown here near the center of the photo is a blue phase of the Snow Goose. Note the white face, and the very dark body. Formerly considered a separate species, the blue phase and the white phase of the Snow Goose are now lumped into one species.