Courtesy of Kenn Kaufman
Common Terns breed from northwestern Canada southward to Montana, and eastward to Newfoundland and New Jersey, southward along the Atlantic Coast to Louisiana. They winter primarily in Argentina, Brazil, and other parts of South America, Africa, Asia, and Australia.
A legend for the range map to the right can be found here
Common Terns are found in a variety of fresh- and salt-water habitats, including estuaries, bays, lakes, and marshes. They nest on islands, marshes, and sometimes lake and ocean beaches.
Common Terns feed primarily on small fish; they also eat invertebrates such as shrimp and other crustaceans, insects, marine worms, leeches, and small squid.
Common Terns breed in colonies, and nest on the ground; nests consist of a shallow scrape or depression, sometimes lined with grasses, seaweed, or shells. They usually lay up to 3 olive-buff eggs, marked with numerous dark brown blotches. Both sexes incubate the eggs and care for the young. Incubation lasts 3 to 4 weeks. The downy chicks are born able to walk, with their eyes open, but stay in the nesting colony until they begin to fly, at nearly 4 week of age.
All North American Common Tern populations are migratory. Terns conduct their high altitude migratory flights mainly at night; there are few records of daytime migration. Because most mortality probably occurs in winter, additional information is needed about existing conditions in the terns' winter territories.