I would let him be, they will eat mostly smaller fish and they are federally protected.

http://birdweb.org/birdweb/bird_details.aspx?id=6

 Quote:
Diet
Insects, fish, and other aquatic creatures make up the bulk of the Pied-billed Grebe's diet. The birds' heavy bills are adapted to crushing large crustaceans, but Pied-billed Grebes are also opportunistic feeders, preying on a wide variety of aquatic creatures including fish. Like other grebes, Pied-billed Grebes will eat and feed their own feathers to their young. It is thought that these feathers help them regurgitate bones and other non-digestible parts of their diet.