Very few people have seen a grebe fly. That’s because
this family of birds almost always flies at night. Although the term red-eye is a tongue-in-cheek way to describe a traveler’s bloodshot eyes from the fatigue of an overnight journey, most grebes do have red eyes. Three of Colorado’s four species of grebes do. It’s thought that they red eye color provides enhanced night-vision for navigation.
Grebe’s usually take off and land from water. Although they can walk or run for a short distance, these birds tend to fall over when they stand up on a solid surface. Their feet are placed so far back on their bodies that they can’t balance or support themselves. Grebes are particularly "land-klutzy" this time of year, when they are doubling their weight in preparation for migration.
In stark contrast to their locomotion efforts on land, grebes are excellent swimmers and divers. You might think they would have webbed feet. They don't! Instead, each toe has lobes extending out on the sides that provide extra surface area for paddling. They have dense and waterproof plumage, and on the underside the feathers are at right-angles to the skin, sticking straight out to begin with and curling at the tip. By pressing their feathers against the 
body, grebes can adjust their buoyancy. They can sit high in the water when propelling forward for lift-off. When threatened, grebes can sink out of sight with just their head and neck exposed—like a periscope.
Colorado is home to four species of these freshwater diving birds. All eat some combination of fish, crustaceans (like crayfish), and aquatic insects.
The pied-billed grebe is small, stocky, and short-necked. It does not have the characteristic red eyes of the other three species. Both sexes have similar markings. It is usually brown or gray in color and has a short, blunt, chicken-like bill that is encircled by a broad black band in summer (hence the name). It is the only grebe that does not show a white wing patch in flight.
The eared grebe has a thin, dark bill that appears to tilt slightly upward. In summer, adult eared grebes are black with golden ear tufts. In winter, they are black, white, and gray, with a white ear patch. On cold, sunny mornings, eared grebes and some other grebe species sunbathe by facing away from the sun and raising their rumps to expose the dark underlying skin to light.
The horned grebe is striking during the summer in its red-and-black breeding feathers. Its "horns" are yellowish patches of feathers behind its eyes that it can raise and lower at will. In winter, its plumage is black-and-white. It has a short thin bill. The horned grebe regularly eats some of its own feathers. The feather forms a matted plug in its stomach that might function as a filter or hold fish bones in the stomach until they can be digested.
The western grebe is the largest grebe in North America. It has a black back and face, long swan-like white neck and underside, and a long, thin bill. Watch them this fall and next spring. Western grebes perform several elaborate dances while mating. In one dance, the two mating birds rapidly begin "running" across the water surface until both birds dive down into the water. In the second dance, the two birds raise their bellies out of the water and caress each other with vegetation held in their bills.