Honeycreeper, po'ouli

Melamprosops phaeosoma

phylum: Chordata

class: Aves

order: Passeriformes

family: Drepanidinae

status: Critically endangered, IUCN Endangered, ESA

range: USA (Hawaii)

Description and biology

The po'ouli (poe-OO-lee) is the most endangered bird in the world today, with only three known individual birds remaining. The name po'ouli means "black face" in Hawaiian. The po'ouli's face is black, but the throat is white, the belly is cream-colored, the top of the head is gray, the back is brown, and the posterior is a light brown. It measures about 5.5 inches (14 centimeters) long and weighs about one ounce (25 grams). It has a short black bill and long dark brown legs.

The po'ouli spends its life hidden in the forests, searching for food in the understory—the leaves and bark of trees underneath a forest's canopy, or top. Its diet consists of snails, insects, and spiders. It builds its nest in the tree branches, constructing it out of twigs and branches. It generally lives alone in its home range area within the forest. The po'ouli's call is seldom heard, but has been described as a sharp repetition of "chick, chick" or "whit, whit." Not much is known about the mating behavior of the species, but po'ouli nests

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observed between April and June have contained one or two baby birds.

Habitat and current distribution

The world's three remaining po'oulis, one male and two females, all live in the Hanawi Natural Area Reserve on Maui (an island of Hawaii). They live in the rain forest on the steep northeastern slopes of Haleakala (an east Maui volcano) at an altitude of about 4,600 to 6,700 feet (1,400 to 2,040 meters). The area receives about 350 inches (900 centimeters) of rain each year. Its vegetation is very dense. The trees in this forest are primarily the native Hawaiian 'ohi'a tree and the 'olapa tree. Fossils indicate that po'oulis were once abundant in the dry forests of Maui. It is likely that the species lived in a much larger range in the past.

Although the 20-acre (8-hectare) home ranges of the three remaining po'oulis are all within 1.5 miles (2.4 kilometers) of one another, they do not overlap. Because of the lack of overlap of home ranges, there is little likelihood that, on their own, the birds would ever meet in the wild. The last known breeding between po'oulis was in 1995.

History and conservation measures

In 1973, several University of Hawaii students first discovered the po'ouli on the slopes of Haleakala. At that time the total population of the species was an estimated 200 birds. Although the population rose to 280 in 1980, the decline since then has been drastic. There have been several causes for the population decline, but no one knows for sure why it has been so severe. The habitat has been damaged by feral pigs (pigs that escaped from domestication and became wild) that root around in the forests, destroying the understory. The rooting of the pigs also creates a breeding ground for mosquitoes, which transmit deadly diseases to birds. Rats and feral cats also present a threat to the species. Birds not native to the forests have been introduced and have brought disease and competed for the po'ouli's food.

DID YOU KNOW?

In 1961, a section of the Hawaii National Park on the upper slopes of the Haleakala Crater on the eastern side of the island of Maui was designated by the U.S. government as Haleakala National Park. Haleakala, the tallest mountain on Maui at 10,023 feet (3,055 meters), is a dormant volcano with a 3,000-foot (914-meter) deep crater. At 7.5 miles (12.1 kilometers) long and 2.5 miles (4 kilometers) wide it is big enough to fit the entire island of Manhattan within it. Haleakala is known for its great beauty and for its variety of habitats and biodiversity. Within the park are coral reefs, grasslands, shrublands, dry forests, bogs, alpine cinder deserts, and an intact rainforest. It has an abundance of plant and animal species, 90 percent of which are endemic (unique) to the Hawaiian Islands. The only mammals native to the island are a bat and a seal. Plants and other animals in what is now the park flourished for millions of years without natural predators, more than 2,000 miles away from any continent. Because the Hawaiian species evolved without predators or disease, when alien species were introduced to their ecosystem by human beings, the native species had little or no defense against them. Today, there are 91 threatened, endangered, or proposed endangered species on the island of Maui. Haleakala National Park is the record- holder for having the most threatened and endangered species of any national park in the United States. This is largely due to the introduction of alien species to the island.

Whatever the cause of the decline in population, the situation has become very urgent. With only three birds left, and each of them more than seven years old, biologists (people who study living organisms) and avian conservationists (people who work to manage and protect the natural bird world) felt they had to make a move to bring about breeding before it was too late. The first attempt was in 2001, when wildlife biologists captured one of the female po'oulis and moved her into the male's home range. Within hours, the female went back to her home range without breeding. In 2003, experts believe the only possibility for saving the species is to take the three birds into captivity in the hope that they will breed within the confines of the Maui Bird Conservation Center.