This is a black-collared hawk. You can see the black collar from which it gets its name. They usually build their nests near water and eat mostly fish, but also snails, water bugs, lizards and rodents. They live throughout Central and South America. I photographed this one from a boat while exploring a small river in the Pantanal of Brazil.
Nikon D300 with Nikkor 200-400mm lens (at 240mm) ISO 800, f/5 at 1/125th of a second