Wildlife & Habitat
In 1965, scientists from the Smithsonian Institution reported only four species of nesting seabirds at Baker Island. Today 11 species nest on the island including boobies, frigatebirds, and almost 1 million pairs of sooty terns. An interesting phenomenon at Baker is the nesting behavior of the lesser frigatebird. Frigatebirds typically nest in trees, but this species forms tight colonies with several hundred eggs laid directly on the ground less than 18 inches apart. Migrant shorebirds also use Baker Island, including Pacific golden plovers, wandering tattlers, ruddy turnstones, bristle-thighed curlews, and sharptailed sandpipers.
A total of 247 fish species have been recorded at Baker Island. In 2004, researchers sighted three rare humphead wrasse in deep water off of the island.
Sixteen species of algae have been collected at Baker, including four species of green algae (mostly Halimeda), two of brown algae (mostly Lobophora), and six of red algae (mostly crustose coralline). Threatened green sea turtles, both juvenile and adult, are abundant at Baker Island, especially on the southern or leeward side of the island. Algae coverage and relief is high in this area and is considered excellent habitat for turtles. Although the island has suitable nesting habitat, no turtles have been observed on land.
Extensive thickets and mounds of living staghorn coral dominate on the eastern reef terraces, though table and plate coral formations are also common. Staghorn, table, brain, rose, and plate corals are found on the reef slopes. Larger heads of lobe, disk, and brain corals - some up to 9 feet in diameter - are found along the deeper slopes. A total of 104 species of corals have now been reported at Baker through 2010. The island’s reefs probably suffered from the global coral bleaching event of 1997-98, and the corals have recovered rapidly. However, massive bleaching is underway at Baker Island as of February 2010.
Baker Island is a model of both the sensitivity of insular ecosystems and mechanisms by which they can recover following disturbance. The low coral island is vegetated by herbs and grasses tolerant of the arid climate. It is surrounded by beaches on all sides composed of sand or coral shingle. The flora of Baker was first surveyed during the 1924 Whippoorwill Expedition, when 15 species were found. In 1965, 24 species were recorded for the island, and in 1993 Refuge staff found two more species. The vegetation is all low coastal strand species with only a few tiny shrubs emerging above the level of the vines and grasses. Eleven additional species were introduced by the colonists in the 1930s but failed to survive the voracious crabs and rats or the extreme temperatures and dryness. A beautiful native bunch grass, Eragrostis whitneyi, was rediscovered by refuge staff in 1993 after not being seen since 1924.
Norway rats were introduced to the island during the whaling days, and cats arrived in 1937. The cats and colonists eliminated the rats in the late 1930s, and the last cat was eliminated in 1964. House mice are still present.
Large numbers of hermit crabs are found on Baker Island. They rely on the abandoned shells of marine snails for their protection. No scientific records of Baker Island’s avifauna prior to the introduction of rats exist. By the time ornithologists visited, few birds were left using Baker Island. The fact that guano was mined there indicates the populations had been much larger prior to contact.