Omao

The ʻŌmaʻo, or Hawaiian thrush (Myadestes obscurus), is a bird endemic to the island of Hawaii. It is a robin-like species, closely related to other endemic Hawaiian thrushes such as the kāmaʻo, the olomaʻo, and the puaiohi. With an estimated population of 170,000, the ʻŌmaʻo is the most common of its kin on the Big Island. Despite a stable population, its vulnerability is heightened due to its limited range and single-island residency.

Identification Tips

Adult ʻŌmaʻo are characterized by a nondescript plumage, with a grayish-brown head that fades to pale gray on the underside. Their backs and primaries are a muted olive brown, while their vents and undertail coverts are whitish. Juveniles mirror the adults in their dull coloration but are distinguished by pale whitish-buff spotting on their wing coverts.

Habitat

The ʻŌmaʻo's range has contracted significantly from its historical expanse across Hawaii. Presently, it inhabits the southern and eastern slopes of the island, predominantly at altitudes above 1,000 meters. This represents 25 to 30 percent of its ancestral habitat. The species thrives in rainforests and can also be found in high shrublands on Mauna Loa. It favors trees such as the ohia and koa and tends to avoid areas overrun by the invasive banana poka vine.

Distribution

Once widespread, the ʻŌmaʻo is now confined to a fraction of its original domain, restricted to specific regions of the Big Island of Hawaii.

Behaviour

The ʻŌmaʻo is primarily frugivorous, though it will also consume insects and other small invertebrates. It is known for its varied vocalizations, which include a catlike rasp, a frog-like croak, and a high-pitched sound reminiscent of a police whistle.

Song & Calls

The ʻŌmaʻo's song is a series of jerky, liquid notes that can be transcribed as whip-per-weeo-whip-per-weet, adding a melodious touch to the Hawaiian rainforests.

Breeding

During the breeding season, ʻŌmaʻo construct bulky nests within trees or tree ferns. They lay one to three bluish eggs, which are then incubated until hatching.

Diet and Feeding

The diet of the ʻŌmaʻo consists mainly of fruits, supplemented by insects and other small invertebrates, which they forage for in their rainforest home.

Conservation status

The ʻŌmaʻo is currently classified as Near Threatened. Its conservation is challenged by habitat destruction due to housing and agriculture, predation by introduced feral animals such as rats, cats, and mongoose, invasive plant species, and feral livestock. However, conservation efforts, including the removal of pigs from areas like the Hakalau Forest National Wildlife Refuge, have been beneficial to the species. Additionally, there are indications of the bird developing a natural resistance to avian malaria at lower elevations.