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Roseate tern (Northeast DPS)

The northeast population of the roseate tern (Sterna dougallii dougallii) nests on barrier islands and salt marshes (typically along with common terns) and forages over shallow coastal waters, inlets and offshore seas [1]. While competing with common terns for food and nesting sites, roseates benefit from the former's aggressive defense of colony sites against predators. While breeding, they primarily feed on American sand lance, a small marine fish. Their nesting success rates may be related to the abundance and proximity of sand lance.

Roseate terns formerly bred from Sable Island, Nova Scotia to Virginia, but no longer breed south of Long Island, NY [1]. Declines were first noted during the late 1800s, as large numbers of birds were killed by the millinery trade to acquire plumes for women's hats. Most historically known breeding sites were extirpated during the 1870s and 1880s. By 1890, just 2,000 pairs were thought to remain. Public outcry, changes in fashion and the creation of the Migratory Bird Treaty Act in 1918 curtailed hunting, enabling the species to rapidly recolonize much of its historic range. By the 1930s, the population had grown to 8,500 pairs with about three-quarter of the birds occurring in Massachusetts. From this peak, however, the species declined to about 4,800 pairs in the 1950s. It maintained this level through the early 1970s. During this period roseate terns were extirpated from New Hampshire, Maryland and Virginia. The only nesters south of Long Island were a very few pairs in New Jersey. During the 1970s, the population again declined, became extirpated from New Jersey, and reached a level of less than 3,000 pairs in 1978. At this point, 90% of all birds were located in just four colonies (Bird Island and Monomy Island, MA; Great Gull Island, NY; and Falkner Island, CT). The decline from the 1930s peak corresponded with increased coastal development and recreation pressure, including the related increase in predacious/competitive herring gulls (Larus argentatus) and great black-backed gulls (L. marinus).

The population may have grown between 1978 and 1988, but inconsistency of survey methods and efforts preclude establishment of a definitive trend [1]. It was listed as an endangered species in 1987. Since then the U.S. population has increased from 2,995 in 1988 to 3,457 in 2004 [2]. The progress was temporarily set back by Hurricane Bob in 1992 and has declined from the 2000 high of 4,310. The species has not increased in the Canadian portion of its range.

CANADA: The Canadian population is small and has remained stable since the mid-1980s at 100-150 pairs [3]. The population is concentrated on a few islands off the coast of Nova Scotia. Small numbers nest on the Îles-de-la-Madeleine, and a pair occasionally nests on Machias Seal Island, a migratory bird sanctuary in the Bay of Fundy. A few nest on Sable Island. Sable Island is an important staging area where birds collect for several weeks before migrating en masse to South America.

MAINE: Roseate terns formerly bred on at least 150 of Maine's 3,000-plus islands, but in recent years have been found on only four to six [4]. The population was never very large, peaking at about 275 pairs in 1931 following the cessation of hunting. It declined to 52 pairs in 1987 before increasing steadily to 289 in 2001 [2]. The 2004 population was 173 pairs. The species is intensively managed on ten islands: gull are removed or limited, decoys and sound recording are used to attract roseate terns, and biologists live on each island to chase away predators and control recreational impacts [4]. All ten are designated as Essential Habitats under the Maine Endangered Species Act, Significant Wildlife Habitats under the Maine Natural Resources Protection Act, or Protection Fish and Wildlife Areas under the Land Use Regulation Commission. The Essential Habitat designation requires that all projects or activities funded or carried out by municipalities or state agencies within a 1/4 mile of the islands are reviewed by the Maine Department of Inland Fish and Wildlife.

NEW HAMPSHIRE: In 1997, the Audubon Society of New Hampshire, the New Hampshire Fish and Game Department, the U.S. Fish and Wildlife Service and others completed the first year of a project to return roseate terns to New Hampshire by discouraging gulls from nesting on White and Seavey islands and attracting common and roseate terns with decoys and bird calls [6]. Six common terns nested in 1997 (the first in the state since the 1950s). By 2004, the population had risen to 2,582 pairs. A single pair of roseate terns nested in 2001 (the first in the state since the 1940s) and increased to 107 by 2004 before declining to 67 in 2005 [2, 7].

MASSACHUSETTS: Almost all Massachusetts roseate terns (and a large portion of the entire U.S. population) nest in Buzzards Bay at Bird and Ram Islands. Smaller populations nest at Nashawena Island and Penikese Island. Outside Buzzards Bay, the species nests on the Monomoy Islands. The statewide population has increased dramatically since 1970 and slightly between 1988 and 2004 [1, 2]. The population was 1,524 pairs in 2004, down from 2,124 pairs in 2000. As the rangewide population has increased faster than the Massachusetts population, the state’s share of the total has declined from about 53% (1988-1992) to about 45% (1997-2004).

Tern habitat restoration and gull control began in Buzzards Bay in the early 1990s in response to the Endangered Species Act listing [8]. These efforts led to roseates colonizing Ram Island in 1994 after being absent since 1973. The Ram Island population has grown rapidly, surpassing Bird Island in 2002. Much of the increase was due to terns relocating from Bird to Ram as the latter experienced severe erosion during the 1990s and 2000s [8]. Nonetheless, the combined population of Buzzards Bay birds has increased significantly from the 1970s to 2004, remaining relatively stable from 1988 to 2004 [2, 8]. Superfund money will be used in 2007 to replenish Bird Island beaches and prevent future erosion [8]. A 2003 oil tanker spill fouled Ram Island beaches. Biologists hazed migrating terns to keep them away from the island, dramatically increasing the nesting colony on Penikese Island, but in the following year only nine pairs nested there. Cape Cod National Seashore is an important staging area where birds collect for several weeks before migrating en masse to South America [A].

RHODE ISLAND. No more than five pairs of roseate terns have nested in Rhode Island since the 1950s [1]. The last breeding record is of two birds in 1984, though immature and summer birds continue to be seen, indicating that the species may still nest in small numbers.

CONNECTICUT. Connecticut's small population is centered on Falkner Island [5]. In 1987 and 1988, about two-thirds of the Falkner population had dispersed from other colonies, especially Bird Island (MA) and Great Gull Island (NY), indicating that the population was not self-sustaining and potentially unstable. Failure of birds to disperse into Connecticut is probably the reason the state's population declined between 1988 and 2004 from 139 pairs to 37 [1, 2].

NEW YORK. The New York population of roseate terns grew from 1,122 in 1988 to 1,616 in 2004 [1, 2]. Growing faster than the U.S. population as a whole, it increased from about 38% of the population between 1988 and 1990 to about 47% in 2002 to 2004. The great majority of the state's birds nest on Great Gull Island, owned by the American Museum of Natural History. Cartwright Island supported substantial numbers in 2001-2004. The eastern tip of Long Island is an important staging area where birds collect for several weeks before migrating en masse to South America [1].

[1] U.S. Fish and Wildlife Service. 1998. Roseate tern recovery plan, northeastern population, first update. Hadley, MA.
[2] Roseate Tern (Northeast Population) Recovery Team. 2005. Numbers of nesting pairs (peak/total) and productivity in chicks fledged per pair of Roseate Terns in the Northeastern United States, 1998-2004 (January 18, 2005 version). Unpublished data provided by Carolyn Mostello, Massachusetts Division of Fisheries & Wildlife, Natural Heritage & Endangered Species Program.
[3] Boyne, A. 2005. Nesting roseate tern pairs in Canada, 1985-2005. Personal communication with Andrew Boyne Wildlife Biologist, Canadian Wildlife Service, Environment Canada, November 22, 2005.
[4] MDIFW. 2003. Roseate tern (Sterna dougallii). Maine's Threatened and Endangered Wildlife, Maine Department of Inland Fisheries & Wildlife.
[5] Spendelow, J. 1995. Roseate Tern Fact Sheet. U.S. National Biological Survey website (www.mbr-pwrc.usgs.gov/mbr/tern2.htm)
[6] New Hampshire Fish and Game Department. 2004. Summary of accomplishments achieved ending FY 2004, sea bird restoration: Isles of Shoals tern restoration project. New Hampshire Fish and Game Department, Concord, New Hampshire.
[7] DeLuca, D. 2005. Personal communication with Diane DeLuca, New Hampshire Audubon, October, 2005.
[8] Buzzards Bay National Estuary Program. 2006. Roseate Tern Recovery In Buzzards Bay. Website (www.buzzardsbay.org/roseates.htm) accessed on January 8, 2006.

Banner photo © Phillip Colla