Habitat
Bridled Terns inhabit tropical and subtropical waters in parts of the Atlantic, Pacific, and Indian Oceans. They nest on coral beaches and rocky and sandy slopes, usually on islands but sometimes on mainland coasts. This species specializes in feeding around rafts of Sargassum seaweed. During the breeding season Bridled Terns forage at sea, usually within 10 km (6 miles) of shore, making them less pelagic than Sooty Terns.
Back to topFood
Bridled Terns specialize in foraging around rafts of Sargassum seaweed. They feed mostly on small fish and also take squid, insects, and crustaceans. Bridled Terns typically forage by swooping down from heights of 3–10 meters (10–33 feet) to pick prey from the ocean surface. They also hover above the water while pecking repeatedly. Less commonly, they make short plunge-dives, although they rarely if ever become fully submerged.
Back to topNesting
Nest Placement
Placed under large rocks, ledges, or overhanging cliffs; deep in rock crevices; or under bushes and trees.
Nest Description
Does not build a nest, or at most creates a slight depression in dirt, coral, or pebble. Nest scrapes are normally unlined, but birds sometimes add some pieces of rock or dead vegetation.
Nesting Facts
| Egg Description: | Whitish, pink, pale green, or brown, with brown, red, lilac, and purplish gray markings. |
Behavior
Bridled Terns are graceful, acrobatic fliers, mixing banking and gliding with slow, deliberate wingbeats. At sea they often perch and even roost on floating objects like coconuts, wood, buoys, Sargassum seaweed, Styrofoam, and sunning sea turtles. They usually forage alone or in small groups, or in multispecies flocks alongside shearwaters, other tern species, dolphins, and sea turtles. They don't form large feeding flocks the way closely related Sooty Terns do. Bridled Terns are loosely colonial, with total colony size ranging from a few pairs to a few thousand pairs. Breeding pairs are monogamous and may maintain pair bonds for six years or more. Both sexes incubate the single egg and brood and feed the chick. The young bird typically fledges after 8–9 weeks, and starts practicing foraging within a week, but continues to be fed on shore by the adults for about five weeks.
Back to topConservation
The International Union for Conservation of Nature lists Bridled Tern's conservation status as Least Concern and estimates the global population size at 400,000 to 1 million mature individuals.
Back to topCredits
BirdLife International. 2019. Onychoprion anaethetus. The IUCN Red List of Threatened Species 2019: e.T22694730A154676367. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T22694730A154676367.en.
Floyd, T. (2025). Field Guide to the Birds of the United States and Canada. Eighth edition. National Geographic Society, Washington, D.C.
Haney, J. C., D. S. Lee, and R. D. Morris (2020). Bridled Tern (Onychoprion anaethetus), version 1.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.briter1.01