Horned Grebe Western population
Scientific Name: Podiceps auritus
Taxonomy Group: Birds
Range: Yukon, Northwest Territories, Nunavut, British Columbia, Alberta, Saskatchewan, Manitoba, Ontario
Last COSEWIC Assessment: April 2009
Last COSEWIC Designation: Special Concern
SARA Status: Schedule 1, Special Concern
Image of Horned Grebe
There are two recognized subspecies of the Horned Grebe: the subspecies auritus, which breeds in Eurasia, and the subspecies cornutus, which breeds in North America. Since the species is represented in Canada only by the subspecies cornutus, the name Horned Grebe is used here without specifying the subspecies.
The Horned Grebe is a small duck-like waterbird, 31 to 38 cm long. Its summer breeding plumage includes a distinctive tuft of showy feathers behind the eye, extending back to the nape of the neck and contrasting sharply with its black head. Its foreneck, flanks and upper breast are chestnut-red, while its back is black and its belly white. Its bill is thin and straight, with a pale tip. Males and females are similar in coloration, although the plumage of the male tends to be brighter. Its winter plumage is black and white and characterized by a black crown and white cheeks, which extend almost around the nape. The juvenile plumage is similar to that of adults in winter, but the upper parts are tinged brown. Chicks have dark stripes, which are particularly visible on the head and neck.
Distribution and Population
The Horned Grebe is found across Eurasia and in northwestern North America, primarily in Canada. In the United States, it breeds in central and southern Alaska as well as locally in some northwestern states. In Canada, it breeds mainly in all of the Prairies, but also in British Columbia, Yukon, the Mackenzie River Valley in the Northwest Territories, extreme southern Nunavut, northwestern Ontario and the Magdalen Islands, where a small isolated breeding population has persisted for at least a century. In Canada, the various colonies are grouped into two populations separated by 2000 km: the Western population, which includes birds breeding from British Columbia to the extreme northwestern part of Ontario; and the Magdalen Islands population, which includes birds breeding in this archipelago and other sporadic breeders that occur in Quebec. In North America, the Horned Grebe winters on the Pacific coast, from the Aleutians and south coastal Alaska to northern Baja California. It also migrates overland, to winter on the Atlantic coast and in the Gulf of Mexico. Many also winter on inland bodies of water. The wintering grounds of the Magdalen Islands population are unknown, but it is presumed that the birds winter along the Atlantic coast of North America. It is therefore possible that the two populations overlap on the wintering range. The Western population of the Horned Grebe is estimated at between 200 000 and 500 000 individuals, with most of the birds found in Saskatchewan and Alberta. Long-term trend analyses based on Christmas Bird Counts show a significant decline of 1.5% per year between 1966 and 2005. Analyses based on annual surveys suggest that the population has declined by approximately 45% since the mid-1960s. Short-term trend analyses show a significant annual rate of decline of 1.25% per year between 1993 and 2005. At this rate, the population will have decreased by 14% over the last three generations.
The Horned Grebe breeds primarily in temperate zones such as the Canadian Prairies, but can also be found in more boreal and subarctic zones. It generally nests in freshwater and occasionally in brackish water on small permanent or semi-permanent ponds which last until autumn, but it also uses marshes and shallow bays on lake borders. These water bodies are found in both open and forested areas. Breeding ponds must contain areas of open water and beds of emergent vegetation that provide nest material, concealment and anchorage, and protection for the young. Little information is available on the particular requirements of the Horned Grebe during migration, but birds have been observed on lakes, rivers and marshes. Some birds follow coastlines for part of their migration. Horned Grebes generally winter in marine habitats, mainly estuaries and bays. They are found in greatest numbers in coastal habitats, particularly in areas that provide some degree of protection. In the Prairies, wetlands have been impacted severely by conversion of grassland to cropland. In addition to permanent habitat loss, Horned Grebes are also facing more short-term or medium-term temporary habitat loss due to drought.
The Horned Grebe is generally a solitary nester, but up to 20 pairs may nest in the same pond if it is sufficiently large and there are abundant food resources. This bird generally breeds around one year of age. Site and mate fidelity have been observed in this species. The Horned Grebe is aggressive when defending its territory, rarely leaving its nest unguarded. The nest is composed of plant matter and is affixed to emergent vegetation, in shallow water. This grebe occasionally builds its nest in areas devoid of vegetation, establishing it on masses of floating algae, cattail, flooded willow, shallowly submerged logs, floating branches or platforms of human origin. Females in the Western population lay on average 5.3 to 5.9 eggs per clutch, whereas in the Magdalen Islands population, the average clutch size is 4.4 and ranges from 3 to 6 eggs. Egg laying stretches over several days, with the eggs laid at one- to two-day intervals. Both parents share incubation of the eggs. The pair can also rebuild its nest and can lay up to four replacement clutches if previous clutches are destroyed. Horned Grebe eggs are taken by racoons, American Crow, Common Raven, Black-billed Magpie and various gull species. Chicks can be subject to predation by Northern Pike and by gulls. Adults may be taken by mink and possibly foxes. The Horned Grebe is a diver that catches and eats most of its prey underwater. Its diet consists primarily of aquatic insects and fish in the summer, and fish, crustaceans and polychaetes (marine worms) in the winter. The Horned Grebe migrates primarily at night over land towards its wintering grounds along the Pacific, Atlantic and Gulf coasts. The Horned Grebe is vulnerable to changes in water quality near its breeding sites.
The factors limiting Horned Grebe populations in Canada are not known, but several possible causes for the decline have been identified, including degradation of wetland breeding habitat and droughts. Permanent loss of wetlands to agriculture and development threaten Horned Grebe populations. Temporary loss of wetlands during droughts can also negatively impact Horned Grebe populations, and the length and frequency of droughts in the Prairies is expected to increase in the future, due to climate change. Eutrophication, i.e., the alteration of an aquatic environment linked to a significant input of nutrients that increases the production of algae and aquatic plants, as well as degradation of nesting sites from the accumulation of fertilizers used in agriculture or other contaminants could also threaten populations. In the Prairies, the major expansion of some predators, including Common Ravens, Black-billed Magpies and racoons, could be a factor causing a decline in the Western population. Type E botulism has been reported in the Great Lakes since the late 1990s and may be an important source of mortality for both resident and migrating waterbirds. Oil spills on their wintering grounds can also threaten Horned Grebe populations. At sea, these birds are particularly vulnerable, since they spend most of their time on the water. Competition with Pied-billed Grebes for breeding habitat could be a limiting factor for the Western population. Similarly, Red-necked Grebes may exclude Horned Grebes from nesting on some ponds. Finally, Horned Grebes become entangled and drown in nets in some commercial fishing areas. It is estimated that 3000 grebes and loons are netted annually by fishers on the southern part of Lake Winnipegosis in Manitoba. On the Great Lakes, birds are killed annually in fishing nets during both spring and fall migrations.
Federal ProtectionMore information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
In the provinces where it breeds, the Horned Grebe (Western population) is not protected by any provincial legislation. However, the species is protected under the Migratory Birds Convention Act, 1994, which prohibits harming migratory birds, their nests or their eggs.
Provincial and Territorial Protection
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
9 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- COSEWIC Assessments (1 record(s) found.)
- Response Statements (1 record(s) found.)
- Action Plans (2 record(s) found.)
- Orders (2 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
- Consultation Documents (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Annual Reports
COSEWIC Annual Report - 2009 (2009)2009 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
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