The colour of this bird is described as slate grey but to me in most light they look black. They are an aquatic bird but their flight is strong. You will often see them running on the top of the water.

They like large ponds, wetlands or temporary flood waters. You usually see them in flocks. The feed on aquatic plants, stems, seeds and algae. When away from the waters edge they deep dive for food. They sleep on the water.

The sexes are alike. Immature birds have a greyish bill, are paler overall and have a whitish throat.