They eat a variety of different types of prey from aquatic insects to crustaceans, fish and frogs. They catch their food by diving under the water, where they are excellent swimmers. In fact when there are predators around they prefer to sink under the water and swim away rather then taking flight.
Although they are commonly confused as ducks grebes do not have webbed feet like ducks do. Their feet have long lobbed toes which are connected by webbing in the middle. This pied-billed grebe that I photographed at Crex Meadows back in September of 2008 was kind enough to give me a good view of one of his feet.