Common Tern

Sterna hirundo

Order CHARADRIIFORMES - Family LARIDAE - Subfamily Sterninae

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1. Cool Facts
2. Description
3. Similar Species
4. Sound
5. Range
6. Habitat
7. Food
8. Behavior
9. Reproduction
10. Conservation Status
11. Other Names

A graceful, black-and-white waterbird, the Common Tern is the most widespread tern in North America. It can be seen plunging from the air into water to catch small fish along rivers, lakes, and oceans.

Cool Facts

• The Common Tern drinks mainly on the wing, gliding with its wings slightly raised and dipping its bill several times into the water.
• Common Terns living along the coast drink salt water. They do not seek fresh water even when it is available nearby. Like many seabirds, they have nasal glands that excrete the excess salt.

• The incubating adult Common Tern flies off its nest to defecate 5-50 m (16-160 ft) away. It deposits its feces indiscriminately in nearby water or on the territories of other terns.

Description

• Size: 31-38 cm (12-15 in)
• Wingspan: 75-80 cm (30-31 in)
• Weight: 93-200 g (3.28-7.06 ounces)

• Medium-sized tern.
• White with black cap.
• Tail long and deeply forked.
• Wings white with dark tips.

Breeding (Alternate) Plumage: Cap solid black. Back light gray. Underparts pale gray. Legs orange-red. Bill orange-red with black tip. Outer wing feathers black at tip. Leading and trailing edge of wings in flight dark. Outer edge of tail feathers dark gray. Rump white, contrasting with gray back.
Nonbreeding (Basic) Plumage: Forehead white. Back of head blackish. Underparts white. Bill all black, or with dark red base. Dark wedge extending into middle of wing visible in flight. Dark shoulder. Legs reddish black.

Sex Differences

Sexes look alike.

Immature

Juvenile with brownish head, and brown bars across back. Immature resembles winter adult, but has even darker primaries.

Similar Species

• No other small tern shows the dark wedge in the spread primaries.
• Forster's Tern similar, but has longer, brighter orange legs, more orange bill with more extensive black tip, whiter wings and belly, paler back, longer tail, a white leading edge to the wings in breeding plumage, and black restricted to small mask around eye and ear in winter.
• Roseate Tern much paler, with long white tail streamers, less dark in wings, and usually an all-dark bill.
• Arctic Tern very similar, but has shorter legs, very little black in wings, darker gray underparts, uniform dark red bill, and longer tail.

Sound

Calls a short "kip" and a harsh "kee-arrr."

»listen to songs of this species

Range

Summer Range

Breeds from Alberta and Northwest Territories of Canada southward to Montana, and eastward to Newfoundland and New Jersey, southward along Atlantic Coast to South Carolina and Louisiana. Also across Eurasia.

Winter Range

Winters along coasts from southern United States southward to southern South America. Also along Africa, Asia, and Australia.

Habitat

Nests on islands, marshes, and sometimes beaches of lakes and ocean.

Food

Small fish. Some invertebrates.

Behavior

Foraging

Plunges into water from flight; may hover briefly before plunging.

Reproduction

Nest Type

Pile of dead vegetation on ground. May have no material.

Egg Description

Olive to buff, marked with numerous small spots and blotches of dark brown, often concentrated around the larger end.

Clutch Size

Usually 2-3 eggs. Range: 1-4.

Condition at Hatching

Downy, eyes open, able to walk but stays in nest.

Conservation Status

Populations severely depleted in late 19th century for millinery trade; recovered with protection. Declined again by 1970s, probably from pesticide poisoning. Some recovery since then, but still in trouble in some areas. Listed as endangered, threatened, or of special concern in many states.

Other Names

Sterne pierregarin (French)
Gaviotin común (Spanish)

Sources used to construct this page:

Nisbet, I. C. T. 2002. Common Tern (Sterna hirundo). In The Birds of North Americaa, No. 618 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.