Scientific Name: Sterna dougallii
Taxonomy Group: Birds
COSEWIC Range: Quebec, New Brunswick, Nova Scotia
COSEWIC Assessment Date and Status Change: April 2009
COSEWIC Status: Endangered
COSEWIC Status Criteria: D1
COSEWIC Reason for Designation: In Canada, this colonial species is part of the northeastern population that breeds on small islands off the Atlantic coast from the Magdalen Islands in the Gulf of St. Lawrence south to Long Island, New York. It winters in South America, from Colombia to eastern Brazil. The most recent (2007) population estimate for Canada was 200 mature individuals occupying 7 locations (approximately 93% are in only 2 locations). The number of mature birds has been fairly stable over the past decade despite recovery efforts. Rescue through immigration of birds from the United States is unlikely since the species is endangered in New England and the population there is also small (circa 7600 mature individuals in 2007). The primary factors limiting the population are predation of eggs, young and adults, low adult survival rates, and stochastic events (e.g. hurricanes).
COSEWIC History of Status Designation: Designated Threatened in April 1986. Status re-examined and designated Endangered in April 1999. Endangered status re-examined and confirmed in October 1999 and in April 2009.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2003-06-05
Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.
Image of Roseate Tern
Two subspecies of Roseate Tern are recognized: the subspecies dougallii in Europe, North America and the Caribbean; and the subspecies gracilis in western Australia. Since the species is represented in Canada only by the subspecies dougallii, the name Roseate Tern is used here without specifying the subspecies.
The Roseate Tern is a graceful, medium-sized, pale seabird that is related to gulls. The white tail is long and forked, and resembles long streamers when the bird is in flight. During breeding, adults are almost completely white except for the black cap and black bill, with red appearing progressively at the base. The breast is white, suffused with pale pink. The wings and back are pale grey, and the upper wing is bordered by blackish feathers. The legs and feet are reddish. Male and female birds are very similar in appearance. In winter, the head is mottled black and white. Juvenile terns have a mottled greyish back and rump, and dark bill and legs. Roseate Terns are very similar to Common and Arctic Terns and are frequently found in their company. The Roseate Tern is distinguished from these two species primarily by its shorter wings, longer tail and paler grey plumage. It is also distinguished by its “chi-vik” call given in flight.
Distribution and Population
The Roseate Tern occurs on coasts and islands along the Atlantic, Indian and Pacific oceans. In North America, two populations of Roseate Tern breed on the Atlantic coast in distinct locations. The northeastern population extends from the Magdalen Islands, in the Gulf of St. Lawrence, south to New York. The second population breeds from Florida and the Bahamas to the Lesser Antilles. The Canadian population of Roseate Terns breeds almost exclusively on a few islands off the Atlantic coast of Nova Scotia, although small numbers of birds also breed on islands in Quebec and New Brunswick. The location of small colonies changes unpredictably from year to year and only two such colonies, both in Nova Scotia, have maintained relatively large numbers of Roseate Terns since the 1980s. Roseate Terns winter in South America, from Colombia to eastern Brazil. Estimates suggest that in 2007, 100 pairs of Roseate Terns were nesting at seven colonies in Canada, with 98 of these pairs found at five colonies in Nova Scotia. The number of adults breeding in Canada has remained relatively stable since the 1980s, when detailed data collection began. The number of Roseate Tern colonies fluctuates annually, with a high of 14 colonies observed in 1999 and a low of 4 in 2003. New sites are found each year. Numbers at the two largest colony sites, Country Island and The Brothers, in Nova Scotia, remain relatively high, although a 50% decline has been noted recently at Country Island. In 2007, Sable Island, in the same province, had the highest number of Roseate Terns since 1993. The small colony on Machias Seal Island, in the Bay of Fundy, New Brunswick, which has been occupied since 1979, was abandoned by terns in 2006, 2007 and 2008. The small colony on the Magdalen Islands, in Quebec, appears to be stable. A small number of birds banded in colonies in the United States have been resighted at The Brothers, suggesting that a Canadian site could be recolonized through immigration from the United States in the event of local extirpation. However, such immigration to Canada is constrained by the fact that the northeastern United States population is itself small and endangered.
Roseate Terns nest in colonies almost exclusively on small coastal islands. They breed at sites covered with vegetation dominated by beach grass and herbaceous plants. In northeastern North America, Roseate, Common and Arctic Terns nest together to take advantage of the benefits of living within a colony. All species of terns join together to threaten and mob invading diurnal predators. Within the same colony, Roseate Terns nest on sites that provide more cover than those chosen by other terns and usually hide their nests under dense grasses, boulders, boards or other washed-up debris. Roseate Terns also nest in boxes, half-buried tires or other artificial shelters. They forage in shallow water close to shore near shoals and tide rips and will hunt for food as far as 20 km from their colony. Little is known about wintering habitat. The largest concentration of wintering Roseate Terns was located in Mangue Seco, Bahia, Brazil. The area is a sandy point on the south side of the mouth of the Rio Real.
Roseate Terns nest in large colonies composed of Common and Arctic Terns, and the vast majority of adults that survive the winter show high site fidelity, returning to the same nesting site each year. Roseate Terns usually begin mating at three years of age. After Roseate Terns arrive in their nesting colonies in the spring, the pairs begin courtship displays. These mating rituals include an elaborate flight in which the male, often carrying a fish, ascends in circles high in the air, closely followed by one or more females. After mating, the female lays a clutch of one to four eggs, but usually two. The parents take turns incubating the eggs for 23 days, but this incubation period can be prolonged at colonies where adults desert the nest at night to avoid nocturnal predation by owls and night herons. In addition to being exposed to the cold, embryos and chicks are thus exposed to greater predation. Roseate Terns, like other tern species, are sensitive to disturbances, whether of human or natural origin, and may desert colony sites, especially if disturbed early in the breeding cycle. After fledging in early August, juvenile Roseate Terns from the northeastern population disperse with their parents to staging areas located from Long Island to Nantucket and Cape Cod, and in the Gulf of Maine. They then migrate south around late August and early September, arriving at their wintering sites in South America in October. Roseate Terns feed on small saltwater fish, most frequently Sand Lance, but also herring, Atlantic Silversides and hake. The main predators at Canadian tern colonies are Herring Gulls and Great Black-backed Gulls. These birds prey on tern eggs, chicks and adults. Red Foxes are major predators of tern eggs on the Magdalen Islands, and Common Ravens and American Crows have been known to take tern eggs at several Nova Scotian colonies. In the absence of predation, Roseate Terns fledge at least one chick per pair. It is estimated that about 32% of fledglings survive to breeding age, and about 83.5% adults survive annually. Estimating Roseate Tern longevity is difficult, but the oldest known banded bird was 25.6 years.
One of the main threats to Canadian Roseate Tern populations is predation and displacement of colonies by Herring Gulls and Great Black-backed Gulls. In addition to being more abundant, these birds prey on tern eggs, chicks and adults. Roseate Terns will abandon a colony subject to heavy predation in search of a new site. In 1997, Roseate Terns abandoned Country Island, almost certainly due to predation by gulls. With increasing human development of coastal areas, suitable nesting sites are becoming much more scarce. Gulls are currently controlled using non-lethal methods (destruction of gull nests and scaring of gulls using noise makers) at both major colonies in Nova Scotia, and predation rates have decreased as a result. As long as gull control continues at these sites, this threat should be relatively low. Increased predation by other species, particularly American Mink, is another threat. Loss of breeding habitat due to erosion is recognized as a threat to the long-term viability of nesting colonies. At The Brothers in particular, the amount of physical habitat available to terns continues to decline due to erosion. Suitable sites could be lost rapidly in the event of one or more severe winter storms. Human activities are disturbing the species, particularly in Mahone Bay, Nova Scotia. Recreational use of beaches is increasing in this area and may be responsible for the loss of Roseate Tern breeding in Mahone Bay over the last 30 years. Industrial development and associated increases in large ship traffic, especially in Country Harbour, where undersea natural gas pipelines and a liquefied natural gas receiving plant are under development, are also threatening the terns. In addition, the increase in aquaculture sites in coastal Nova Scotia may pose a threat if it reduces the amount of prey available or disrupts habitat where terns forage. Major storms, such as Hurricane Bob, which passed through the principal staging area for Roseate Terns in August 1991, can hinder population recovery. Finally, unidentified sources of wintering mortality can affect Canadian Roseate Tern populations.
The Roseate Tern is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
In Quebec, Nova Scotia and New Brunswick, the Roseate Tern is protected under the Migratory Birds Convention Act, 1994, which prohibits harming migratory birds, their nests or their eggs. In Nova Scotia, the species is also protected under the province’s Endangered Species Act. In Quebec, the Roseate Tern is currently considered likely to be designated threatened or vulnerable under the Quebec Act Respecting Threatened or Vulnerable Species. The small Magdalen Islands colony occurs in the Pointe de l’Est National Wildlife Area, which is federal land protected under the Species at Risk Act (SARA). Its habitat is also protected under the Quebec Act Respecting the Conservation and Development of Wildlife, which protects islands and peninsulas inhabited by colonial birds and which are considered to be wildlife habitats.
Provincial and Territorial Protection
Status of Recovery Planning
Recovery Strategies :
Name Recovery Strategy for the Roseate Tern (Sterna dougallii) in Canada
Status Final posting on SAR registry
Name Amendment to the Recovery Strategy for the Roseate Tern (Sterna dougallii) in Canada RE: Critical Habitat Identification and Action Planning
Status First posting on SAR registry
Name Amended Recovery Strategy for the Roseate Tern (Sterna dougallii) in Canada
Status Final posting on SAR registry
Roseate Tern Recovery Team
Marty Leonard - Chair/Contact - University or college
Julie McKnight - Chair/Contact - Environment Canada
Phone: 902-426-4196 Fax: 902-426-6434 Send Email
Recovery Progress and Activities
Summary of Progress to Date Roseate Terns declined dramatically in the early 20th century, in large part due to artificially high gull populations; the larger and more aggressive gulls displaced Roseate Terns from their nest sites and preyed on tern eggs and nestlings. Although gull predation still requires management, the threat has been substantially reduced. Access to the human-provided food that had artificially increased gull populations has been restricted, causing gull populations to decline over the last two decades. Open dumps have been replaced by cleaner refuse facilities, and fisheries waste is also lower. In 2004 approximately 120 pairs of Roseate Terns nested in Canada, close to the Roseate Tern Recovery Strategy goal of 150 pairs. The largest Roseate Tern colonies in Canada are on Country Island (40 pairs in 2004; Recovery Team objective: 50 pairs) and the Brothers Islands (76 pairs in 2004; Recover Team objective: 80 pairs) in Nova Scotia. With so few nesting colonies, and with their vulnerability to predators such as mink, Roseate Terns require continued conservation management. In order to help recover Roseate Terns in Canada, efforts are underway to establish a third nesting colony. Summary of Research/Monitoring Activities The Roseate Tern population on the Brothers Islands is monitored weekly by a local steward (reports available at www.ted.ca). A resident field crew monitors the Country Island population. A monitoring program is also in place in Mahone Bay, where the Bluenose Coastal Action Foundation is attempting to establish a new nesting colony. Additionally, the Nova Scotia Department of Natural Resources and the Canadian Wildlife Service conduct surveys of all tern colonies in Nova Scotia every four years. One important question for Roseate Tern recovery is whether a conservation program would be more successful by promoting fewer, larger colonies or by promoting more, smaller nesting colonies. The results of a research project addressing this question on Sable Island are ambiguous, and more work is needed. A bird-banding program is ongoing at both the Brothers Islands and Country Island colonies. Bird-banding will allow researchers to follow movements of our birds among Canadian and American colonies. Summary of Recovery Activities The amount of land available for nesting on the Brothers Islands has been increased by enhancing the habitat ? patches of vegetation were covered with tarps and then gravel. Nesting shelters, which mimic natural cover features used by Roseate Terns, were placed on Brothers Islands in the early 1990s and on Country Island in 1998. On Brothers Islands, Roseate Terns use the nesting shelters almost exclusively, but on Country Island, nesting shelters were not used until 2004, when one pair used them. Researchers are interested to see if use of nest shelters increases on Country Island. On Country Island and, to a lesser extent, on Brothers Islands, efforts are made to deter gulls, crows and ravens from nesting on the island. However, a mammalian predator is currently posing a challenge for Roseate Tern recovery; in 2003, a single mink killed almost the entire population of chicks on the Brothers Islands colony. The animal was captured, but another mink devastated the colony in 2004. One of the objectives of the recovery team?s draft recovery strategy is to create at least one more managed colony of Roseate Terns. The first attempt to establish a new colony took place on Machias Seal Island, but initial results were poor and the project was abandoned. An in-depth study was carried out to select the location for a second attempt (see: www.coastalaction.org/pages/pro_new/tern.html). Mahone Bay was selected, in part, because it once held about one-third of Canada?s nesting Roseate Terns. In 2003, a careful evaluation of the islands in Mahone Bay (susceptibility to flooding, habitat suitability, landowner support) resulted in the selection of Quaker Island as the focus of conservation activities. In 2004, gull deterrence strategies were employed, nesting shelters were built and nesting colony sounds were broadcast to attract terns. These techniques successfully attracted Common Terns to nest, which is important because Roseate Terns select nest sites near Common Tern colonies. This is excellent success for the first season and conservation efforts will continue on Quaker Island in 2005. Hopefully Roseate Terns will nest at this site in the future. URLs:www.ted.cawww.coastalaction.org/pages/pro_new/tern.html
Hinterland Who's Who: Roseate Tern: http://www.hww.ca/hww2.asp?pid=1&cid=7&id=69
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.
38 record(s) found.
- COSEWIC Status Reports (2 record(s) found.)
- Response Statements (1 record(s) found.)
- Recovery Strategies (1 record(s) found.)
- Action Plans (2 record(s) found.)
- Critical Habitat Statements (2 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
- Permits and Related Agreements (26 record(s) found.)
- Residence Description (1 record(s) found.)
- Critical Habitat Descriptions in the Canada Gazette (1 record(s) found.)
- Critical Habitat Orders (1 record(s) found.)
COSEWIC Status Reports
Response Statement - Roseate Tern (2009-11-25)In Canada, this colonial species is part of the northeastern population that breeds on small islands off the Atlantic coast from the Magdalen Islands in the Gulf of St. Lawrence south to Long Island, New York. It winters in South America, from Colombia to eastern Brazil. The most recent (2007) population estimate for Canada was 200 mature individuals occupying 7 locations (approximately 93% are in only 2 locations). The number of mature birds has been fairly stable over the past decade despite recovery efforts. Rescue through immigration of birds from the United States is unlikely since the species is endangered in New England and the population there is also small (circa 7600 mature individuals in 2007). The primary factors limiting the population are predation of eggs, young and adults, low adult survival rates, and stochastic events (e.g. hurricanes).
Critical Habitat Statements
COSEWIC Annual Reports
COSEWIC Annual Report - 2009 (2009-08-28)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.
Permits and Related Agreements
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