Habitat
Blue-billed White-Terns breed throughout the tropical and subtropical Pacific and Indian Oceans on small oceanic islands, including both low-lying coral islands and higher volcanic islands. Most nesting colonies are on remote islands, but this species also nests in highly developed areas, including downtown Honolulu. Blue-billed White-Terns forage mainly over inshore waters, shoals, and banks, but they also forage far out to sea, particularly outside the breeding season.
Back to topFood
Blue-billed White-Terns feed primarily on fish, and to a lesser extent, squid. They usually forage over schools of predatory fish, which drive smaller fish to the ocean surface. Blue-billed White-Terns then capture small fish by plucking them from the water surface or snatching them from the air when they jump out of the water. Unlike most temperate terns (e.g. Common Tern), Blue-billed White-Terns do not plunge-dive to catch food, but they do swoop down to the surface for prey.
Back to topNesting
Nest Placement
Egg placed directly on tree branches (up to 18 meters or 59 feet above the ground), buildings, small coral rocks, and ledges.
Nest Description
Blue-billed White-Terns do not build a nest, instead laying the egg on any surface where it can be balanced.
Nesting Facts
| Egg Description: | White to grayish white, with dark streaks and spots. |
Behavior
Blue-billed White-Terns are skilled fliers, swerving, gliding, swooping, and soaring effortlessly. This species is less social than many other terns—they do not gather in flocks, although they do join loose foraging groups with other seabird species. Pairs are monogamous, and most pairs remain together between breeding seasons. Both sexes select the egg-laying site (there is no nest), incubate the single egg, and feed the chick. In the absence of a traditional nest, the chick has large feet, toes, and claws to help it remain on the bare surface (branch, ledge, building surface) where the egg was laid. The young bird fledges after about seven weeks, and the parents continue to feed it for an additional 7–8 weeks.
Back to topConservation
The International Union for Conservation of Nature lists Blue-billed White-Tern's conservation status as Least Concern and estimates the global population size at 50,000–99,999 mature individuals.
Back to topCredits
BirdLife International. 2022. Gygis candida. The IUCN Red List of Threatened Species 2022: e.T216558801A219774358. https://dx.doi.org/10.2305/IUCN.UK.2022-2.RLTS.T216558801A219774358.en.
Chesser, R. T., S. M. Billerman, K. J. Burns, C. Cicero, J. L. Dunn, B. E. Hernández-Baños, R. A. Jiménez, O. Johnson, N. A. Mason, and P. C. Rasmussen (2025). Sixty-sixth supplement to the American Ornithological Society’s Check-list of North American Birds. Ornithology 142:1–18.
Floyd, T. (2025). Field Guide to the Birds of the United States and Canada. Eighth edition. National Geographic Society, Washington, D.C.
Niethammer, K. R., L. B. Patrick, G. M. Kirwan, B. K. Keeney, P. Pyle, and S. M. Billerman (2025). Blue-billed White-Tern (Gygis candida), version 1.0. In Birds of the World (B. K. Keeney and S. M. Billerman, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.whiter4.01
Pratt, H. D., P. L. Bruner, and D. G. Berrett (1987). A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press, Princeton, NJ, USA.