White Tern

The White Tern, Gygis alba, is a delicate seabird, a vision in white, with a graceful flight that belies its tenacious hold on life in the vast tropical oceans. Its plumage is immaculate, and it sports a slender, pointed black bill, perfect for snatching fish from the sea.

Identification Tips

To identify the White Tern, look for its pure white feathers, which cover its entire body, and its contrasting black bill. With a wingspan stretching between 76 and 87 centimeters, it is a small but noticeable bird. The absence of a nest and its unique egg-laying habits on bare branches are also distinctive.

Habitat

The White Tern is a pelagic bird, favoring the open ocean. It is often found along coastlines and moves inland to wooded areas during the breeding season.

Distribution

This tern has a broad range across the Pacific Ocean, from the coasts of Chile and Colombia to New Zealand, and along the eastern and southern coasts of Asia. It is also found in the Indian Ocean and the coast of South Africa, with occasional sightings in Japan, Madagascar, Mexico, and some Atlantic islands.

Behaviour

The White Tern is known for its unusual reproductive strategy, laying its egg directly on a thin branch without constructing a nest. This adaptation may reduce the risk of nest parasites. The species is resilient, capable of re-laying eggs if lost and living for over four decades.

Song & Calls

The White Tern communicates with soft, high-pitched calls, often heard during its aerial displays over the ocean or near its breeding sites.

Breeding

Breeding takes place on coral islands, where the White Tern lays its single egg on a bare branch or a small fork in a tree. Remarkably, the chicks are born with strong feet to grip their precarious perch from the moment they hatch.

Similar Species

The White Tern can be confused with the Fairy Tern, Sternula nereis, but can be distinguished by its nesting habits and location. The Little White Tern, Gygis microrhyncha, was once considered a subspecies but is now recognized as a separate species.

Diet and Feeding

The diet of the White Tern consists mainly of small fish, which it catches with precision by plunge diving into the ocean.

Conservation status

Globally, the White Tern is listed as Least Concern by the IUCN Red List, thanks to its large range and several robust colonies. However, in New Zealand, it is classified as Nationally Critical due to past predation by introduced species, though populations are recovering following predator eradication efforts.