The small gulls with forked tails belong to a group of birds known as terns. Terns are seabirds in the family Sternidae and are closely related to gulls, skimmers, and skua. They are known for their slender bodies, long forked tails, and pointed bills that enable them to deftly catch fish and other prey while flying over water. There are over 40 species of terns that inhabit oceans, coastal areas, and inland waterways around the world.
Some of the most common and widespread terns with forked tails include:
Common Tern
The common tern (Sterna hirundo) is found across temperate regions in North America, Europe, Asia, and Australia. It has gray upperparts, white underparts, a black cap on its head, and a bright red-orange bill with a black tip. Its forked tail has long outer feathers. Common terns reach lengths of 35–43 cm and have wingspans of 76–87 cm.
Breeding and Migration
Common terns nest in colonies on coasts and islands. Their breeding range spans across the northern hemisphere. After nesting, they migrate long distances to wintering grounds in the southern hemisphere. Some populations make journeys of over 15,000 km annually between breeding and wintering areas.
Diet
These opportunistic feeders eat small fish, shrimp, mollusks, and insects. They plunge-dive from the air into water to catch prey, often immersing their entire bodies. Common terns may also pick up food items while swimming on the water’s surface.
Arctic Tern
The Arctic tern (Sterna paradisaea) lives up to its name, breeding in Arctic regions in North America and Eurasia. It has gray upperparts, white underparts, a black cap, and a red bill. Its deeply forked tail has extended outer feathers. Arctic terns are medium-sized with lengths around 33–37 cm and wingspans of 75–85 cm.
Migration
Arctic terns make the longest migration of any bird, flying from their Arctic breeding areas to the Antarctic coast for the southern summer. Roundtrip journeys can cover over 90,000 km annually.
Diet
Their diet consists mainly of small fish and marine invertebrates like squid and shrimp. They plunge dive from heights of 1-15 m to catch prey near the water’s surface.
Forster’s Tern
Forster’s tern (Sterna forsteri) inhabits coastal areas, marshes, and lakes in temperate North America. It has gray upperparts, white underparts, a black cap, orange-red legs and bill, and a deeply forked tail. Forster’s terns reach 28–33 cm in length and have wingspans of 66–76 cm.
Breeding
Nesting occurs near water in marshes and on beaches from April to August. Nests consist of scrapes lined with vegetation and are often in small colonies. Both parents incubate the 2-3 eggs and feed the chicks after hatching.
Diet
They primarily eat small fish captured by plunge diving from heights of 1-6 m. They also consume invertebrates like shrimp, crabs, and insects, often picking them from the water’s surface while swimming.
Elegant Tern
The elegant tern (Thalasseus elegans) lives on the Pacific Coast from southern California to Mexico. True to its name, it has a slender, graceful appearance. Its gray upperparts contrast with its white underparts and black cap. Its bright orange bill is tipped black in breeding season. Elegant terns measure 28–36 cm long with wingspans around 89–97 cm.
Breeding
Nesting takes place April through July in large colonies on coastal islands and beaches. Both sexes help build a nest scrape lined with vegetation and shell fragments. The female typically lays 2 eggs that are incubated for around 3 weeks.
Diet
Elegant terns forage over shallow coastal waters, plunging to catch small fish like anchovies, sardines, and smelt. They also eat some invertebrates like shrimp and squid.
Roseate Tern
The roseate tern (Sterna dougallii) breeds on islands along the northeast coast of North America, northwestern Europe, and southeast Africa. Its namesake pinkish tinge is most noticeable during breeding season. Roseate terns have pale gray back and wings, white underparts, a black cap, and long, deeply forked tails. They reach lengths of 33–37 cm with wingspans around 76–84 cm.
Breeding
Nesting occurs from May to August in colonies on beaches and islands. Both sexes assist in nest building, egg incubation, and caring for the chicks after hatching. Like many terns, roseate terns are defensive and aggressive around nests.
Diet
They forage for small fish, dipping to the water’s surface while flying along coastal areas. Sand lance, herring, and capelin are common prey. They occasionally eat shrimp and other small invertebrates.
Least Tern
The least tern (Sternula antillarum) is the smallest tern in North America. As its name implies, it reaches just 21–25 cm in length and has a wingspan of 48–53 cm. Least terns have pale gray upperparts, white underparts, a black cap, yellow bill with a black tip, and a forked tail.
Breeding
Nesting occurs from April to August along coastal beaches, inland rivers, and lakeshores. Scrape nests are simple, shallow depressions lined with pebbles, debris, or vegetation. Least terns are territorial and dive-bomb perceived threats.
Diet
They plunge-dive from brief hover positions to catch small fish in shallow waters. Common prey includes minnows, anchovies, killifish, and topminnows. They also eat some insects.
Characteristics of Small Fork-Tailed Terns
While the terns described vary somewhat in size and habitat, they share some core similarities:
- Slender, lightly-built bodies
- Long, pointed wings
- Forked or deeply forked tails
- Pointed bills adapted for catching fish
- Plunge-diving fishing method
- Nesting in colonies on coasts and islands
- Migratory habits in many species
Their combination of adaptations makes these agile, aerial hunters well-suited to pursue fish and other prey. The forked tail and long wings provide excellent aerial maneuverability and lift for plunge diving after prey. Pointed bills easily grasp slick, wriggling fish. Many species make epic migrations spanning thousands of kilometers between nesting and wintering locales.
Tern Conservation Status
Some terns with deeply forked tails face conservation threats and have protected status:
Species | Conservation Status |
---|---|
Arctic Tern | Least Concern |
Roseate Tern | Near Threatened |
Least Tern | Least Concern |
Elegant Tern | Near Threatened |
Though not globally threatened, elegant and roseate terns face localized threats. Roseate terns suffered historical hunting for feathers and declines from habitat loss. Elegant terns are impacted by disturbance, nest flooding, and habitat degradation. Ongoing conservation efforts aim to protect tern populations and their breeding colonies.
Conclusion
The common trait of a forked tail identifies a group of adept, fish-hunting terns that inhabit coastal regions worldwide. Their adaptations for aerial plunging allow them to thrive around water. While not all terns are highly threatened, protecting breeding colonies and migration stopover sites remains important for conservation of these elegant, global travelers.