Puaiohi  (Myadestes palmeri)

Classified as Critically Endangered (CR) on the IUCN Red List (1).

The common name of this bird, puaiohi, comes from the sound of the male’s mating call, a brief, reedy and high-pitched sound (3), which the male utters every ten seconds whilst displaying at twilight to attract female attention (4). The female does not sing for mating purposes, but does use a lower intensity call to mark the territory and, during disputes, both sexes will click their beaks (3). Adult puaiohis have dark brown upperparts, with a paler and greyer underside. Juveniles have more speckled plumage, becoming less patterned with age. The bill is black and slender, a distinctive white ring surrounds the eye, and the legs are pink (2) (3).  

Endemic to a single Hawaiian Island, Kauai, where it is confined to a region of 32 square kilometres (2).

The puaiohi is found at only a single upland site, between 1,000 and 1,500 metres above sea level, in the Alaka`I Wilderness Preserve (2). It inhabits forested, steep-sided ravines and prefers to nest next to streams where ferns and mosses provide a high level of cover (3).

The puaiohi is a monogamous bird, with the breeding pair remaining together to rear up to four broods per year, although there is evidence of some mating outside the stable pairing (3). Each pair returns to the same breeding territory each year, where the female lays two eggs into a cup-shaped nest lined with mosses. The eggs are incubated for a fortnight, after which the chicks remain in the nest for around 16 to 22 days before reaching independence at four weeks old (3).

The puaiohi can breed at one year old, but some will wait a year or two longer, during which time they will help raise another pair’s brood (3). Nest helpers collect extra food for the chicks and help defend the nest against owls that prey on chicks, and feral cats and rats that will attack newly fledged birds (3).

Fleshy fruits form 82 percent of the puaiohi’s diet, with the rest comprised of invertebrates such as insects and snails. When the puaiohi has young to feed it will increase the amount of protein-rich invertebrates it catches from 18 percent to 57 percent of its total diet (3).

The puaiohi, and other native Hawaiian birds, face a range of threats including disease, introduced predators and competitors, habitat damage, forest clearance and human population growth (5). Many of these threats interlink making the problems harder to resolve. 

Feral pigs on the island damage the lower layers of the forest as they move through it and dig for food (2), and also create wallows of mud which provide a breeding site for mosquitoes, the main vector of introduced diseases (3). Mosquito-carried diseases, and forest clearance by humans, are responsible for driving the puaiohi from its lowland habitat into upland areas where there are fewer mosquitos (3). Fortunately, there is some evidence that certain puaiohis are developing resistance to avian malaria, one of the mosquito-borne diseases, so this disease may cause less mortality in the future if the resistance spreads (6).

Rats pose another problem as they raid puaiohi nests and compete for food, and invasive plants threaten to replace the plants that the puaiohi relies on for both food and shelter (2). Thankfully, hurricanes have not threatened the puaiohi as much as many other native Hawaiian birds because its ravine habitat is relatively sheltered (4).

The puaiohi is protected by federal and state law and its range is part of a reserve, the Alaka`I Wilderness Preserve, established in 1964 (3) (7). A successful captive breeding programme is in place for the species and numerous captive-bred individuals have been released back into the wild (2). As a consequence, the breeding population numbers are rising, so the species may be moved from Critically Endangered to the less threatened status of Endangered in the future (2).

Additional conservation measures that have been recommended include the removal of rats and cats from the Alaka`I Wilderness Preserve and protecting the area from further invasive plants and animals. Rat poison placed near puaiohi nests and captive bird release areas has been quite successful (2).

View information on this species at the UNEP World Conservation Monitoring Centre.

To learn more about conservation efforts in Hawaii see:

• The Nature Conservancy:
  http://www.nature.org/wherewework/northamerica/states/hawaii/projectprofiles/art23204.html

For more information on this and other bird species please see:

• BirdLife International:
  http://www.birdlife.org