The Bison Wallow is a small pool at the south end of the Bison Field which provides water and minerals for the bison herd. It is also a good place to scope out the field in search of rare geese among the thousands of Canada Geese that congregate there during their Spring and Fall migration. This field is probably the single most reliable place in the Chicago region to find both Greater White-fronted Geese and Ross's Geese. This field is also the best place on site to look for Cattle Egrets.

The wallow itself has also produced some good birds over the years. These include Buff-breasted Sandpipers (1994), American Avocet (2000), and Eared grebe (1987).