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ABSTRACT--
We describe two sequential nestings of a pair of Poo-uli (Melamprosops phaeosoma), a critically endangered Hawaiian honeycreeper. Similarities to nesting of most other honeycreepers included: nest site in ohia lehua (Metrosideros polymorpha Gaud.) canopy; breeding in March through June; monogamous breeding system with the male helping build the nest, feeding the female throughout each nesting event, and feeding the chicks, but not incubating or brooding; and complete nest sanitation. Notable differences were the paucity of songs and calls by the parents and inclusion of snails in the diet of nestlings. Clutch size was probably two eggs for both nests. High winds, rain, or both influenced parental behavior: the female stayed longer on the nest and took shorter recesses in poor weather. Weather did not affect rates at which the male fed the female on the nest; however, the feeding rate increased from the egg to the chick stage probably because food was passed on to the chicks. At nest #2, parents fed young chicks (<14 days old) more often in good than in poor weather; data were insufficient for old chicks. Weather is usually poor throughout the year in the relictual range of the Poo-uli and is likely to impact nesting success. The first nest failed in poor weather. The second fledged a single young 21 days-old. Diet of nestlings appeared to consist of a higher proportion of insect larvae than older birds, which are reported to eat mostly snails.
ABSTRACT--
We describe two sequential nestings of a pair of Poo-uli (Melamprosops phaeosoma), a critically endangered Hawaiian honeycreeper. Similarities to nesting of most other honeycreepers included: nest site in ohia lehua (Metrosideros polymorpha Gaud.) canopy; breeding in March through June; monogamous breeding system with the male helping build the nest, feeding the female throughout each nesting event, and feeding the chicks, but not incubating or brooding; and complete nest sanitation. Notable differences were the paucity of songs and calls by the parents and inclusion of snails in the diet of nestlings. Clutch size was probably two eggs for both nests. High winds, rain, or both influenced parental behavior: the female stayed longer on the nest and took shorter recesses in poor weather. Weather did not affect rates at which the male fed the female on the nest; however, the feeding rate increased from the egg to the chick stage probably because food was passed on to the chicks. At nest #2, parents fed young chicks (<14 days old) more often in good than in poor weather; data were insufficient for old chicks. Weather is usually poor throughout the year in the relictual range of the Poo-uli and is likely to impact nesting success. The first nest failed in poor weather. The second fledged a single young 21 days-old. Diet of nestlings appeared to consist of a higher proportion of insect larvae than older birds, which are reported to eat mostly snails.
INTRODUCTION--
A husky Hawaiian honeycreeper drably colored in shades of brown, the Po`o-uli (pronounced Poh-oh-u-lee and translated "black-faced") was named for its most striking feature by M. Kawena Pukui, noted authority on Hawaiian language and culture. This followed the bird's remarkable discovery in 1973 by T. Casey (TC), J. Jacobi, and other college students on a University of Hawai`i expedition to the rainforest wilderness of Haleakala Volcano on Maui Island. Since its unexpected debut, the Po`o-uli has become a star representative of the unique and dangerously rare species among the Hawaiian avifauna.
The Po`o-uli has revealed few details of its biology. In the 1970s, the single population of a few hundred individuals inhabited only 600 hectares of rain-drenched, tangled elfin forest on the windward slopes of Haleakala. The Po`o-uli seldom calls or sings and typically is seen long before it is heard. One encounters them singly, in pairs, or in family groups, often in association with other foraging insectivorous honeycreepers. A Po`o-uli typically hops into view along a tree limb, head down, methodically searching bark and epiphytes. It pauses only to rip apart loose bark, lichen clumps or moss cushions for hidden invertebrate prey. Its diet is yet another strange example of specialization among the Hawaiian honeycreepers, for besides consuming arthropods and fruit, the Po`o-uli eats extraordinary numbers of land snails. Despite this innovation, its monogamous breeding system and nesting biology show no divergence from those of most other honeycreepers.
The Po`o-uli is listed as an Endangered Species by both federal and state governments. The State of Hawai`i manages the Hanawi Natural Area Reserve to protect the bird's habitat, and a new recovery program conducted by the National Biological Service is attempting to improve the future of fewer than 10 Po`o-uli surviving.
INTRODUCTION--
The Maui Parrotbill is an endangered Hawaiian honeycreeper that was first collected in 1892 by Henry Palmer and described by Rothschild (1893-1900). No Hawaiian name for the species survives. Currently restricted to the remote high-elevation rain forest of eastern Maui, the Maui Parrtobill was thought to be extinct until its rediscovery in 1950 (Richards and Baldwin 1953). Today the population is estimated to be about 500 birds (Scott et al. 1986).
Before the 1980s, various naturalists had encountered Maui Parrotbill but had collect little detailed information (Wilson and Evans 1890-1899, Rothschild 1893-1900, Henshaw 1902, Perkins 1903, Banko 1968, Scott and Sincock 1977). Very little was known about the species until biologists began natural history studies in the 1980s, and the first confirmed active nest was not discovered until 1993 (Van Gelder 1993, Locwood et al. 1994). The Maui Parrotbill is a small, olive-green bird with a relatively large, parrotlike bill, which it uses to rip into branches and stems, to pluck and bite open fruit, and to lift bark and lichens in search of concealed invertebrates. Its is one of the most sexually dimorphic of Hawaiian honeycreepers: Males are much larger than females, and their underparts are brighter yellow. Chicks are fed by regurgitation, and because fledglings remain dependent on their parents for 5 months or longer, sightings are frequently of family groups.
The ecology of this species remains poorly know, but ongoing research should provide much neeeded information, especially about factors affecting productivity. Such understanding will be essential in developing management strategies to help safeguard the future of the Maui Parrotbill.
ABSTRACT--
A single, relictual population of Palila (Loxioides bailleui), a Hawaiian honeycreeper, survives on the slopes of Mauna Kea volcano on the island of Hawai'i, where it feeds principally on flowers and green seeds of the mamane tree (Sophora chrysophylla). The Palila was listed as an endangered species by state and federal governments because of continuing damage to its habitat by browsing feral and mouflon sheep (Ovis aries and O. musimon) and goats (Capra hircus) and because of the bird's restricted range and low numbers. Ecology of the Palila was studied from 1987 to 1996. Annual population estimates fluctuated between 1 600 and 5 700 and averaged 3 400 birds. Estimates varied with availability of mamane seeds, which are less abundant in drought years. In drought years, most birds did not attempt to breed, and survival rates were lower because of a shortage of food. Availability of mamane seeds also showed large seasonal variability. While some nests were preyed upon by owls (Asio flammeus), cats (Felis catus), and rats (Rattus rattus), losses were high at the end of the season from unexplained death of eggs and chicks. Genetic studies did not implicate inbreeding depression. Neither avian malaria nor avian pox appeared at this site, where the mosquito vector was absent. However, weather and food shortage worsened towards the end of the nesting season. Availability of food and habitat remain the principal factors limiting increase in the Palila population. Recovery efforts now focus on reducing numbers of feral ungulates, fire management, removing mammalian predators, and developing techniques for captive propagation and introduction to currently unoccupied sites within the bird's former range. Reforestation adjacent to the Mauna Kea Forest Reserve would allow the Palila population to expand and grow.
ABSTRACT--
The Poouli (Melamprosops phaeosoma) is an endangered Hawaiian honeycreeper found only on Maui, Hawaii. It was rare at the time of its discovery in 1973, but by 1997 was on the brink of extinction with fewer than six individuals left. Two specimens were collected for the description of the species, but both proved to be immature by comparison with a pair of adults at a nest. Until 1997 no Poouli had ever been captured alive, and consequently descriptions of adult Poouli were produced from field observations. In 1997, I captured an adult male Poouli which is described here for the first time. Detailed comparisons of the plumage of this adult with that of an immature specimen and previous descriptions of the species are discussed in this paper, as are differences in plumage between adult and immature males and females that may aid the sexing and ageing of birds in the field.
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