Tachybaptus is a genus of small members of the grebe family birds. It has representatives over much of the world, including the tropics.These grebes breed in small colonies in heavily vegetated areas of freshwater lakes. They may move to more open or coastal waters when not breeding, and birds in those areas where the waters freeze may be migratory.Like all grebes, they nest on the water's edge, since the legs are set very far back and they cannot walk well.