Twenty species of Grebes make up the Family Podicipedidae in the Bird Order Podicipediformes. These small to medium sized diving birds are found in waters throughout the world with the exception of Antarctica. Grebes share many similar characteristics with Loons, though they occur in more diverse aquatic habitats including large lakes, flooded scrubland, roadside ditches and coastal bays.
Fossilized remains for the order Podicipediformes were discovered from the Cretaceous period of some 80 million years ago. The modern day grebe seems to have evolved more than 30 million years ago during the Oligocene epoch.
Physically, the grebe can be distinguished by short wings, legs that are set back with lobed toes, sharp and pointed bills, long necks and little tail. Grebes, like loons walk poorly on land due to the positioning of their legs which are set to the back to aid in swimming and diving for prey. Their lobed toes with highly flexible joints serve them well for propulsion and steering underwater. Sleek bodies and dense bones allow them to dive down to depths as deep as 90 feet. Grebes typically forage for food near the water's surface and dive for aquatic invertebrates such as insects and crayfish, small fish, aquatic vegetation and amphibians. Peculiarly, the grebe ingests a large number of their own feathers, believed to protect their stomachs from puncture wounds by bones and hard items entering their intestines.
Grebes breed with more flair than any other bird species. Their courtship rituals are elaborate and captivating and include intense displays of posture and side by side racing across the surface of the water while reared up on their feet. Nesting is done quite typically with decaying vegetation which is anchored on aquatic plants. The female lay from 2-6 eggs with an incubation period of 20-30 days. From birth, the young grebe is able to dive and swim. The adult grebe carries their young on their backs to shelter and protect.
There has been a worldwide decline in many grebe species due to alteration of habitat as well as the introduction of predatory fish species and the ingestion of toxins such as PCBs. Several of the species have been placed at risk including the Horned Grebe which according to a National Audubon Society study declined in numbers by 70% between the years 1966-2003.
Following is an introduction to the most common species of grebe that exist in the Northern Hemisphere.
Eared Grebe (Podiceps nigricollis)
One of the smaller of the grebe species, the black-necked or eared grebe has a slightly upturned slender bill with dark plumage. During the summer months they grow golden colored ear tufts. This species is very social and tends to prefer saline water but breeds on shallow freshwater wetlands. During courtship the eared grebe display in a "mutual penguin-dance" and a "mutual parallel rush in penguin posture" where they are seen running across the water side by side in a balletic dance. The females lay from 1-4 eggs with an incubation period of 20-22 days.
Clark's Grebe (Aechmophorus clarkii)
The Clark's Grebe shares the same range as the Western Grebe and in the past was believed to be of the same species. Unlike the Western Grebe, the Clark's Grebe has a white face and has a brighter yellow bill and white surrounding its eyes instead of black. This bird breeds on large lakes with reeds and is a colonial nester. Displaying the same elaborate courtship display as the Western Grebe, they rise up and rush across the top of the water together. The females lay from 3-4 eggs with a 23 day incubation period.
Horned Grebe (Podiceps auritus)
A small bird with a small head and bill the horned grebe sports black and white plumage during the winter and striking red and black breeding feathers with horns of golden yellow during the breeding season. During breeding displays these birds enhance their appearance by causing their golden horns to stand erect from each eye and strike a pose similar to a penguin with what has been called the "ghostly penguin dance". Nesting occurs on piles of aquatic vegetation that generally rest on a rock just below the water's surface where the females lay from 3-8 eggs with a 24 day incubation period.
Pied-Billed Grebe (Podilymbus podiceps)
This small grebe is known for sinking below the water out of site when it feels in danger. A plump little bird with a tufted white rump and a short thick whitish bill with a black band, this grebe has lobed toes for swimming and a distinct and very loud call. Breeding on seasonal and permanent ponds the female lays her eggs in an open bowl of floating vegetation. The females lay from 3-10 eggs with a 21-27 day incubation period. The young chicks cannot swim well and do not go into the water unless on their parents back during the first week. By the age of four weeks they spend all day and night on the water.
Western Grebe (Aechmophorus occidentalis)
The Western Grebe, like the Clark's Grebe, is a medium sized black and white grebe with a long neck and long, sharp bill. It can be distinguished from the Clark's Grebe by its black face and black surrounding its eyes. The Western Grebe performs an elaborate courtship ritual of rushing across the water side by side while holding their bodies erect. Following the rush ceremony, if they are still interested in each other, they then perform what is called the "weed dance" where each bird dives for aquatic vegetation then turns from side to side while holding it high. Nests are anchored to surface plants where the females lay from 3-4 eggs with a 23 day incubation period. The young are carried on the parent's backs for 2-4 weeks and fed through the 8th week.
From recent counts, the Western, Clark's and Horned Grebes have begun to decline in numbers due to the depletion of or actions that have had a direct negative impact on their habitat. Steps are currently being taken by conservation agencies to help flag and watch these species to ensure a healthy future.
Sources:
Sibley, David Allan. 2001. The Sibley Guide to Bird Life & Behavior. Alfred A. Knopf, New York.
Perrins, Christopher M. & Elphick, Jonathan. 2003. The Complete Encyclopedia of Birds and Bird Migration. Chartwell Books, New Jersey.
Burnie, David & Wilson, Don E. (Eds.). 2005. Smithsonian Institution Animal: The definitive visual guide to the world's wildlife. Dorling Kindersley, London & New York.