Least Grebe Life History

Habitat

Least Grebes are most common on small freshwater ponds and lakes, especially those with emergent and aquatic vegetation, which provides both good foraging habitat and places to hide from predators. They also use ephemeral (temporary) ponds, brackish wetlands, mangrove swamps, and sluggish rivers. They are rare on saltwater. In some parts of their range they occur in lakes and marshes as high as 8,200 feet above sea level. These tiny grebes may even breed in small wetlands such as water-traps on golf courses or roadside ditches.

Food

Least Grebes eat mainly insects and small vertebrates. When foraging above the water surface, they pick insects, insect larvae, tadpoles, and small frogs from vegetation or from the water’s surface. They dive below the water to chase fish or pluck prey from submerged vegetation. They may also snap at passing flying insects. They swallow most prey immediately, but for larger items they surface in order to soften prey in the bill before swallowing. Prey include waterbugs and aquatic beetles of many kinds, dragonflies and damselflies and their nymphs, ants, spiders, crayfish, small crabs, frogs, tadpoles, and small fish. Like other grebes, they swallow some of their own body feathers, which form a plug in the stomach (pyloric plug) that protects the digestive tract from sharp bones.

Nesting

Nest Placement

Set near the water’s edge, usually anchored to vegetation or to the bottom.

Nest Description

A mound of wet, decayed plant material that protrudes a few inches above the waterline. Nests average about 9.8 inches in diameter, with a central depression 2.8 inches across and 0.8 inches deep.

Nesting Facts

Behavior

Like the larger grebe species, Least Grebes form monogamous pairs that perform memorable courtship displays during breeding (which can happen at any time of year). Their call is a rapid trill given as a duet between male and female. These calls do not always indicate active courtship and probably serve to maintain the pair bond throughout the year. Courting males give a loud, high-pitched gamp, swimming along with head raised, body plumage sleeked, and the puffy white flank feathers raised above the waterline. Pairs also perform a "rushing ceremony" reminiscent of larger grebe species. Male and female raise up suddenly in the water and race forward several feet, propelled by their feet, then drop to the water again, preening and picking at the surface of the water. One bird (presumed the male) gives a loud nasal call several times during this display. They may also duet in low flights over the water together. Both male and female share incubation and chick-rearing duties, with tiny stripe-headed chicks often riding on the backs of parents, even when the adults dip underwater.

Conservation

Partners in Flight estimates a global breeding population of 500,000, only a small fraction of which occurs in the United States. Least Grebe ranks an 8 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. Their dependence on freshwater wetlands means that they are sensitive to habitat loss, drainage, and water quality issues.

Credits

Kushlan, J. A., M. J. Steinkamp, K. C. Parsons, J. Capp, M. A. Cruz, M. Coulter, I. Davidson, L. Dickson, N. Edelson, R. Elliott, R. M. Erwin, S. Hatch, S. Kress, R. Milko, S. Miller, K. Mills, R. Paul, R. Phillips, J. E. Saliva, W. Sydeman, J. Trapp, J. Wheeler and K. Wohl (2002). Waterbird conservation for the Americas: The North American waterbird conservation plan, version 1. Washington, DC, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

Storer, Robert W. (2011). Least Grebe (Tachybaptus dominicus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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