Guam Kingfisher

The Guam kingfisher, called sihek in Chamorro, is a medium-sized kingfisher from the US territory of Guam, 20 to 24 cm long, with an iridescent blue back and a rusty-cinnamon head. Males have cinnamon underparts, while females and juveniles are white below. In the wild it was a secretive forest bird that dived to the ground to catch insects, spiders, lizards and small crustaceans, and nested in cavities in soft-wooded trees and termite nests. It was last seen in the wild in 1986 and now survives only in a captive breeding programme.

About the Guam kingfisher

The Guam kingfisher is a small, brightly colored forest kingfisher found only on the Pacific island of Guam, where it is known as the sihek. It belongs to the Todiramphus kingfishers of the Pacific and was once treated as part of the Micronesian kingfisher. It became extinct in the wild after the brown tree snake reached Guam.

Its scientific name is Todiramphus cinnamominus. The name Micronesian kingfisher once covered the Guam bird together with the kingfishers of Pohnpei and Palau. Differences between the islands in body shape, behavior, and ecology were judged large enough to split them into separate species: the Guam kingfisher, the Pohnpei kingfisher, and the rusty-capped or Palau kingfisher. A single specimen from Japan's Miyako Islands, collected in 1887 and called the Ryukyu kingfisher, was sometimes listed as a further subspecies. The International Ornithological Congress declared that form invalid in 2022, so the Guam kingfisher is now treated as a species with no subspecies.

It is a medium-sized kingfisher, 20 to 24 cm (7.9 to 9.4 in) long, and brilliantly colored. The back and upper wings are iridescent blue to blue-green, and the head is a rusty cinnamon with a dark stripe through the eye. The bill is large, dark, and flattened from side to side, and the legs are dark.

The sexes differ below. Adult males have cinnamon underparts, including the breast and the undersides of the wings. Females and young birds are white underneath. Calls of these Micronesian kingfishers are generally a raspy chatter.

Behavior and diet

Despite belonging to a family famous for diving into water after fish, the Guam kingfisher hunts on land. It is a sit-and-wait predator. From a perch, it watches the ground and then drops down to seize prey, much as a fishing kingfisher plunges into a pond. In the wild it fed on insects, including grasshoppers, as well as spiders, small lizards and other small reptiles, and small crustaceans.

On Guam it was a forest generalist that fed on the ground and tended to be secretive. Pairs nested in cavities they dug out of soft-wooded trees and out of termite nests built in trees. Like the other Micronesian kingfishers, the birds held permanent territories year-round, defended by breeding pairs and family groups.

Raising young is a shared job. Both the male and the female care for the chicks, and some offspring stay with their parents for an extended period. Research suggests the thermal environment, meaning the temperatures the birds live in, may influence how well they reproduce.

Range and habitat

The Guam kingfisher is native only to Guam, a United States territory in the western Pacific. Its close relatives live on neighboring islands: the Pohnpei kingfisher on Pohnpei and the rusty-capped kingfisher in Palau, both in moist tropical lowland forest.

On Guam the kingfisher was a forest bird. It used trees soft enough to excavate, or termite nests built in trees, for its nest holes. It was last seen in the wild on Guam in 1986.

A new wild population has since been started outside the native range. In September 2024, nine young Guam kingfishers from U.S. breeding programs were released on Cooper Island in Palmyra Atoll, in the Pacific. The birds began breeding there, and the first eggs were seen in April 2025, the first Guam kingfisher eggs laid in the wild in more than 40 years. A return to Guam itself would be possible only if protected, snake-free areas can be established.

Guam kingfisher vs other Micronesian kingfishers

The three former Micronesian kingfisher populations are now separate species. All are brilliantly colored, medium-sized kingfishers with large, flattened bills and dark legs, and all defend permanent territories as pairs and family groups. The main differences are plumage and the island each calls home.

Conservation status

The Guam kingfisher is listed as Extinct in the Wild on the IUCN Red List, based on a 2024 BirdLife International assessment. In the United States it is also listed as endangered.

The cause of its disappearance is well established. The brown tree snake was accidentally carried to Guam shortly after World War II, probably hidden in ship cargo or aircraft. With plenty of prey and almost no predators, the snake multiplied to peak densities of more than 100 per hectare (40 per acre). It wiped out most of the island's native forest vertebrates, and twelve native bird species have been lost, including the Mariana fruit dove and the Guam flycatcher. Only two native forest birds, the Mariana swiftlet and the Micronesian starling, still survive on Guam.

After it vanished from the wild, the species survived only through captive breeding, with fewer than 200 birds as of 2017, split between breeding facilities on the U.S. mainland and on Guam. A Species Survival Plan manages that population. The 2024 release on Palmyra Atoll was the first step in plans for its reintroduction to the wild, and the eggs laid there in 2025 were the first laid in the wild in more than 40 years.