Horned Grebes breed on small, shallow, freshwater ponds with emergent vegetation such as rushes, sedges, and reeds. They also use artificial ponds such as industrial borrow pits that have filled with water, so long as some emergent vegetation is present. Migrants may appear on almost any body of water, including rivers, if large enough for landing and take-off. During periods of severe winter weather, Horned Grebes regularly land along roadways or in parking lots, which probably look like water bodies from the air. These "wrecks" are dangerous because the birds have trouble taking off again. Wintering Horned Grebes may be found on freshwater or saltwater, sometimes in sizable flocks. They sometimes remain all winter in the same vicinity; but at other sites they can be highly mobile, searching out schools of small fish that follow warmer water during the course of a winter.Back to top
Breeding Horned Grebes eat small fish, salamanders, frogs and tadpoles, crayfish, leeches, amphipods (tiny crustaceans), and a great variety of aquatic and aerial insects and their larvae. They capture most prey by diving and stabbing with the bill, but they are also skilled at catching flying insects as they pass by; and they often glean insects from the water’s surface or from floating vegetation. In migration and during winter, small crustaceans and fish form most of the diet, but they also take polychaetes (marine worms). Most Horned Grebes breed on shallow lakes, where they capture prey both in the water column and at the bottom. In larger water bodies, they dive only to perhaps 20 feet or so, where they pursue mostly small fish. Large flocks sometimes synchronize dives, possibly to forage cooperatively.Back to top
Males and females select the nest site together, build the nest together, and also erect several similar platforms used only for copulation. Nests are placed within 10 feet of the shoreline, usually in an area with emergent vegetation.
Nests are masses of aquatic vegetation piled up so that the top portion is 2–4 inches above waterline. Some are floating nests that are bound to emergent vegetation, others built on rocks or earth, and still others are anchored to the bottom of the pond. Nests measure about 14–16 inches across, with a depression of about 4 inches in the center for the eggs.
|Clutch Size:||3-8 eggs|
|Number of Broods:||1 brood|
|Egg Length:||1.7-1.8 in (4.43-4.58 cm)|
|Egg Width:||1.2-1.2 in (3.02-3.09 cm)|
|Incubation Period:||23-24 days|
|Egg Description:||White to brownish or bluish green.|
|Condition at Hatching:||Downy and active; can swim and dive within one day, but usually stay on nest platform.|
Horned Grebes usually form monogamous pairs. Pairs form during spring migration or even in winter. Pairs arrive at breeding lakes together and immediately begin pair-bonding displays, called “ceremonies." Each ceremony consists of a series of stereotyped postures and movements. In Horned Grebe, these include swimming together, gathering and presenting weeds, shaking the heads, and other displays. They have a further set of displays associated with copulation. They are highly territorial around the nest and often drive away other pairs, though in some areas, nests are so close together that the birds appear to nest colonially. Males and females share incubation and often bring each other prey items when changing shifts. Both parents care for the young and defend them aggressively. When young reach about 2 weeks of age, the parents sometimes divide the brood and care for different young. The young are usually independent after 4 weeks, and pairs may separate at that point.Back to top
Horned Grebes breed mostly north of the limit of the North American Breeding Bird Survey, so it's difficult to estimate their population trends. They are fairly numerous but appear to have had population declines over the last half-century. Partners in Flight estimates the global breeding population at about 620,000, with an estimated 250,000 breeding in North America, and rates the species an 11 out of 20 on the Continental Concern Score, indicating it is a species of low conservation concern. The species is often killed in fishing nets during the winter months, is vulnerable to contamination by pollutants in water, and is susceptible to oil spills.Back to top
Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.
Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.
Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.
Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.
Stedman, Stephen J. (2000). Horned Grebe (Podiceps auritus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.