Coots are not members of the duck family but rather are related to rails and cranes. They have large lobes on their feet that are used for swimming and also fold as they walk on land. The feet seem bigger than you would expect for this sized bird; the large feet help support them on marsh vegetation. As adults they have a dark grey body, red eye and white bill. Sometimes they will have a red dot on the white shield above the bill. They feed primarily on vegetation and algae but will also take insects and small animal prey. I have watched them forage across the lawns at Green Lake picking up small grubs, especially after a light rain and bite off pieces of grass. They tend to form large flocks during the winter. During the breeding season, they become territorial and pairs defend their piece of the marsh. Adults will build a floating nest by piecing together cattails and other vegetation to make a platform for their eggs. The young leave the nest soon after hatching and stay with their parents until they are grown.
Check them out the next time you visit Green Lake. I have seen them on all sides of the lake as I walk the loop.