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Gulls and Terns: The Difference and Similarity

The Gulls and Terns

White-fronted Terns & Red-billed Gulls

White-fronted Terns & Red-billed Gulls

Just offshore, a sleek bird with pointed wings hovers over the water, bill aimed down. In a flash, it drops with a splash and flies off, a small, silvery fish glistening in its bill. A least tern has grabbed a meal for its hungry chicks.

Gulls and terns are birds belonging to the Laridae family. They can be found in or near a wide variety of habitats. These include coastal areas, lakes and marshes, agricultural fields, golf courses, and even deserts. They live throughout the world.

Lives of Gulls and Terns

Black-backed gulls

Black-backed gulls

Gulls will eat just about anything. This includes live and dead fish, insects, and worms. They will even eat the unguarded young of other birds. Gulls drop shellfish (such as clams) onto rocks to shatter the shells to get at the meat. Discarded human food is also a part of a gull's diet.

Many species, including the herring and great black-backed gulls, visit landfills where rotting food is readily available. Others, including the laughing and ring-billed gulls, will flock around people tossing bread crumbs. Terns are primarily fish-eaters. They hover above the water and dive bill-first when they see small fish.

Gulls and terns gather into large colonies during the breeding season. In most species, pairs remain together for life. During the non-breeding season, they may become more solitary. The birds migrate from their northern breeding ranges to more southerly locations.

Some species travel very long distances. Arctic terns are widely believed to have the longest migration of any bird. Each year they travel from their northern breeding grounds in the Arctic to the southern waters around Antarctica, and then turn back. This round-trip migration covers more than 20,000 miles (32,000 kilometers).

Gull nests can be large mounds or mats of vegetation, feathers, old rope, and other material. But their nests may also be no more than a mere scrape on a sandy beach. (One species, North America's Bonaparte gull, nests in trees.) Both parents usually build the nest. Tern nests are typically little more than depressions in the ground.

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Gulls and terns lay from one to four oval eggs. These are greenish to cream-colored, sometimes flecked with dark spots. Both parents incubate the eggs for 19 to 29 days. The young hatch with a downy coat. In larger species the young may take up to 56 days to leave the nest. Parents raise one brood, or group of chicks, each year. It takes two to five years for the birds to reach breeding age. Smaller species mature more quickly than larger ones. Gulls and terns live about five years.

Characteristics of Gulls and Terns

Lesser black-backed gull

Lesser black-backed gull

Conservation

Arctic Terns

Arctic Terns

In the past, gulls were a source of food for humans living in coastal areas. This contributed to declines in the birds' populations. Entire tern colonies were once killed for their feathers, which were used to decorate hats.

Gulls and terns still face threats today. They can become sick and die from oil spilled in the ocean or when their food is contaminated by toxic chemicals. And they are preyed upon by non-native animals such as rats, dogs, and cats.

The least tern is endangered in parts of its range due to the loss of sandy beaches. The roseate tern is also endangered in parts of its range. It has been unable to fully recover from being hunted for its feathers. In the United States today all gulls and terns are protected by law.

Gulls and terns look very similar. They both have relatively long legs for walking and webbed feet for swimming on the surface of the water. But there are some differences. Gulls have long wings, thick bodies, and rounded heads. Terns are typically smaller than gulls. And their wings and bills are more pointed. Several tern species have a crest at the back of the head.

Most gulls and terns have white bodies as adults. Young gulls are grayish brown. Several tern species, such as the black tern of North America, are dark. Some gulls and terns have black caps or hoods during the breeding season. Bills range from yellow to reddish orange.

The largest member of the Laridae family is the great black-backed gull. It measures about 21/2 feet (.76 meter) in length, with a wingspan of about 5 feet (1.5 meters). It is found from eastern North America to western Europe. The smallest species is the little tern of Europe. It measures just 8 to 11 inches (20 to 27 centimeters) in length. Gulls and terns make a wide range of squawking, screeching, and "bugling" sounds.

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