Common Tern
Scientific Name: Sterna hirundo
New York Status: Threatened
Federal Status: Not Listed
Description
The common tern is the most widespread and abundant tern in New York. This species has a light grey back, white underparts, a white, deeply forked tail, and a glossy black cap and nape. Its pointed wingtips are noticeably darker than those of the roseate tern with which it associates. The tail is also shorter and has darker outer edges. In breeding plumage, the bill is blood red with a black tip. The immature and winter adult lack enough of the black crown to appear as though balding, and the bill is uniformly dark. The call is a harsh, rolling "kee-urr," with a downward inflection. The average common tern is 13-16 inches in length, has a wingspan of about 31 inches and weighs about 4.2 ounces.
Life History
From late April to mid-May, common terns return to their northern breeding colonies. These colonies may contain several hundred to several thousand birds, including roseate, least and gull-billed terns, and black skimmers on Long Island. The nest is a simple scrape built above the high tide line in sand, gravel, shells or windrowed seaweed. It is usually lined with vegetation. A clutch of 2-4 (usually 3) eggs is laid during late May through July. Both sexes share incubation duties for 21-27 days. The young fledge about 28 days after hatching. One brood per season is typical, but re-nesting is common when the first nest is destroyed. By mid-October, the terns depart for wintering grounds, sometimes flying as fast as 40 mph.
The common tern secures its prey in a fashion similar to other terns, striking the water in shallow dives or skimming the surface. It feeds on small fish up to 3-4 inches in length. Occasionally, shrimp or aquatic insects are taken. One banded individual was found to be 25 years old upon recapture.
Common tern range map from Birds of the World,
maintained by the Cornell Lab of Ornithology.
Distribution and Habitat
Common terns inhabit sand and shell beaches, grassy uplands and rocky inland shores in North and South America, Eurasia, and northern Africa. This species breeds in North America along the Atlantic Coast from the northern Maritime Provinces of Canada to South Carolina, and occasionally in the Gulf of Mexico or on large inland lakes.
Wintering grounds are from its southernmost breeding areas on the Atlantic Coast to northern Ecuador and Brazil. In New York, common terns nest predominantly on Long Island, but they are also known to breed on small natural and artificial islands (power cribs, piers, navigation sites, etc.) in Lake Erie, Lake Ontario, the St. Lawrence and Niagara rivers, and Oneida Lake in central New York.
Status
In the early 1900s, common terns were almost extirpated by plume hunters. Protective legislation in 1918 allowed this species to make a comeback in the 1920s and 1930s. Today, competition with ring-billed gulls for nest sites in upstate New York and disturbance on Long Island breeding beaches are the reasons for decline. Many colonies are being forced to breed in salt marsh habitats as a result of the increased human use of beaches and competition with herring and great black-backed gulls. Flooding and predation are problems as well.
Management and Research Needs
Researchers from private and public conservation organizations and concerned volunteers census tern breeding areas on Long Island annually. Extermination of rats has been undertaken in some areas where they were a problem in the past. In upstate New York, some nesting success has occurred as a result of the construction of gull exclosures on the terns' nesting islands.
