At this writing, the world’s population of Po`ouli consists of three birds, scattered over about half a square mile of dense, high-elevation rainforest in the Hanawi area of East Maui.
The home range of each bird covers little more than 20 acres. Since the birds’ home ranges contain no areas of overlap, the likelihood of a breeding pair forming — even supposing, as some scientists do, that one of the birds is male and two are female — is practically nil.
Over the last few months, wildlife managers in the state Department of Land and Natural Resources and the federal Fish and Wildlife Service have been debating what to do, if anything, to save the Po`ouli (Melamprosops phaesoma).
The prognosis for recovery of this species is about as black as the tiny bird’s face mask.
The causes for the bird’s decline are not well known: predation by rats, habitat disturbance by pigs, disease, possible loss of food source (tree snails, insects, bugs) or competition for prey with hardier, introduced bird species have been hypothesized. All probably have contributed to the Po`ouli’s sinking numbers.
Other factors have been suggested. Given the fossil record, which shows that the Po`ouli was once abundant in dry, or mesic, forests of Maui, the present home of the bird may simply be a last retreat, with its preferred habitat now gone from the face of the Earth. Such a mistake was made with the Nene, or Hawaiian goose; because it was found only in the high elevations, wildlife managers assumed the bird preferred the cold climate. Today, most scientists believe the Nene in Haleakala crater are at the uncomfortable extreme edge of their range, there only because they have been forced out of more desirable habitat.
The Po`ouli may be in similar straits. As Storrs Olson of the Smithsonian Institution puts it, the subfossil record shows that the Po`ouli, which “was quite common in dry, leeward slopes of Maui, down to 300 feet,” is probably a “pretty unhappy bird” in an area soaked with 440 inches of rain a year.
The reasons for the Po`ouli’s decline may never be known fully. Most pigs have been removed from the immediate area of the Po`ouli. An intensive rat-control effort has reduced the rodent population. But these efforts may well be too little and too late. Even supposing that the rainforest of Hanawi is pristine, it still may be uninhabitable, over the long term, for a dryland forest bird now in perpetual Diaspora.
A Cryptic Bird
The Po`ouli was not known to exist until 1973, when a team of graduate students discovered it. Seven years later, a survey estimated the Po`ouli population to number about 280. Since then, the population has plunged precipitately. From 1975 to 1985, the population density fell 90 percent, dropping from 76 birds per square kilometer in 1975, to 15 in 1981, and to 8 in 1985.
Thirteen years later, the population has dwindled to near nothingness, as well as its spatial range, now covering little more than one square kilometer — less than half a square mile. The known population is three birds; more could exist, given the bird’s secretive nature, but probably not many more, given the exhaustiveness of the searches undertaken in recent years.
Can the Po`ouli be saved? A draft environmental assessment, prepared by the DLNR and the Fish and Wildlife Service, was released in September. Three public hearings were held that month (two on Maui, one in Honolulu). Comments were continuing to come in at press time.
According to Sharon Reilly, the DLNR’s endangered species biologist, many of the comments are critical of the notion that the state and the federal governments should be spending so much of their effort and limited budgets on saving a single, on-the-brink species rather than trying to protect the entire ecosystem of which it is a part.
Those comments are somewhat off the mark, Reilly believes. As noted in the draft EA, the state has been managing the Hanawi Natural Area Reserve in a manner that is intended to protect not just the Po`ouli, but all other native flora and fauna, including the Maui Parrotbill, `Amakihi, `I`iwi, `Apapane, and `Akohekohe.
(The area might also be home to the Maui Nukupu`u, the Maui `Akepa, and — a long shot — the Bishop’s `O`o. No confirmed sightings of these birds has been made in years, although an unconfirmed sighting of a Nukupu`u was made in July 1998; still, given the rugged terrain of the area, it is possible that some of these rare birds may yet be in the forest.)
Whatever decision is made on the Po`ouli, the ongoing habitat management efforts at Hanawi will continue, the draft EA states. Any action “will be done in concert with, not instead of, a continued and expanded program of habitat restoration in East Maui, predator control, searches for additional Po`ouli, and research to determine the factors that have led to the decline of the Po`ouli and other forest birds in the area.”
The draft environmental assessment describes those steps that could be taken, over and above habitat management (the no-action alternative), to increase the Po`ouli’s chance of recovery.
Move the Male
The first of these is to capture the male and relocate him to the home range of a female, where he would be released as soon as possible. Protocols for release would be refined using surrogate insectivores, such as the Japanese bush warbler (an introduced species) or the Maui Creeper.
The bird — or, if more than one bird is translocated, the birds — would be monitored by means of a radio transmitter. “If a pair bond is formed, every effort will be made to locate the nest(s), and if the nest is accessible and egg removal has a high chance of success, all first-clutch eggs will be removed.” Eggs would then be taken to the Olinda captive-rearing facility on Maui, the Keauhou facility on the Big Island, “or another approved facility for incubation and rearing.”
Past experience with the release of wild adult birds has not been encouraging, the draft EA notes. “There would be a very real likelihood that the translocated wild adult bird(s) would simply disperse from the release site and not pair up with the opposite sex bird, based on the results of previous translocation attempts in Hawai`i that have involved adult Palila, `Oma`o, and Hawaiian Hawks or `Io.”
This alternative “would also present a high risk of losing track of the released bird, as the radio transmitters to be used will likely have a life span of only about 2 weeks.” And, it notes, “with this and all of the following alternative actions, there will be no guarantee that the Po`ouli will be able to form a reproductive pair even in the best of circumstances, as the birds may be incompatible or already too old to reproduce.”
A further complication: The determination of the sexes of the birds is not as unequivocal as one might hope. Genetic sexing tests performed on cells collected from feathers are extremely difficult, in the case of species where there is no extensive reference library of genetic material. One of the foremost experts on these birds is Paul Baker, in whose opinion one bird supposed now to be female is more likely a male, based on his observation of its behavior (presenting nest material to a female Maui Parrotbill, and engaging in courtship behavior with a female Po`ouli) and plumage.
Form a Pair
The second action alternative involves capturing a bird and moving it to an aviary built in the home range of a second, opposite-sex bird, “where the bird would be held in an attempt to attract the opposite sex bird.”
“If the opposite sex bird is attracted to the cage and the birds appear to be forming, or are likely to form, a pair bond, the bird may be released from the holding cage/aviary after being fitted with a radio transmitter. Or, to strengthen the pair bond before release of the bird, the opposite sex bird may be captured and placed in the holding cage/aviary with the translocated bird.”
Should the pair bond, both birds would be released into the wild. Eggs from their nest would be removed, if the nest is accessible, for incubation at a captive-rearing facility.
Hold On Site
The third alternative involves capturing two birds and holding them in a field aviary, in the hope they would breed and nest there. “If a pair forms and successfully nests, all first-clutch eggs would be removed… Second-clutch eggs may also be collected… If propagation is successful, the resulting young and, possibly, the adults themselves would be released into the wild.”
This option would be one of the costliest, both in terms of money and harm to the environment. It would involve construction of a field aviary, construction of staff living quarters in Hanawi, and the hiring and maintenance of adequate staff to manage the birds on site for an extended time. “Given the remoteness of the site and the vagaries of weather that many times prevent travel into and out of Hanawi NAR [Natural Area Reserve] by helicopter, this option also presents logistical difficulties for maintaining adequate health care for the birds.”
Take Into Captivity
The fourth option involves capturing the birds (two or three) and holding them in a field aviary in Hanawi until the birds have formed a pair or are accustomed to captivity. At that time, the birds would be transferred to a captive propagation facility.
The fifth option is similar, but would avoid holding the birds in a field aviary to acclimate them to captivity. Instead, they would be transferred as soon as possible to a captive-propagation facility.
The goal of captive propagation would be “first and foremost to prevent the extinction of the Po`ouli through increasing the numbers of individuals and second to re-establish the Po`ouli in the wild where the threats that have contributed to its decline are controlled.”
The Response
In the last few years, millions of dollars have been spent on single-species recovery efforts in Hawai`i. Probably the most celebrated of these has been the `Alala recovery effort, which, in recent months, has suffered serious setbacks with the deaths of young birds released from captivity into the wild.
Growing disappointment with the `Alala, and perhaps with the captive rearing program as well, may be an element in forming the views of many of those who commented on the draft EA. Many urged the state and federal government to redirect their efforts to saving ecosystems rather than single species — despite the draft EA’s statement that ecosystem management efforts at Hanawi would continue, whatever decision was made with respect to the Po`ouli.
Among the most ardent comments (and, at 47 pages, also the longest) was one from Alan Lieberman, head of the Hawai`i operations of The Peregrine Fund. Although The Peregrine Fund was invited to Hawai`i by the Fish and Wildlife Service to run a captive propagation program for endangered birds, Lieberman’s comments were highly critical of the plan to bring adult birds into captivity. In a statement distributed at the public hearings on the plan, Lieberman argued that insectivorous birds have a poor record of survival in captivity. (However, The Peregrine Fund has raised a Maui Parrotbill, which is also an insectivorous bird, from a wild-collected egg.) Lieberman expressed his preference for the “hard release” proposal — releasing the female into the home range of the male.
In addition, Lieberman’s statement said (in a footnote to a chart comparing alternatives), “TPF has declined to participate in the captive management of adult Po`ouli collected from the wild because the mortality risks for bringing adult, insect-eating songbirds into captivity are unacceptably high. If Po`ouli eggs are found The Peregrine Fund will collect the eggs for artificial incubation. Wild, adult Po`ouli would probably not adjust to living in captivity after growing up in the wild. They would probably not breed in a cage and are likely to suffer nutritional and stress-related problems.”
(The Peregrine Fund would not provide Environment Hawai`i with a copy of Lieberman’s comments on the draft EA. Nor would Lieberman return calls or answer questions we posed in writing.)
The Costs
Teresa Menard, a graduate student in zoology and the University of Hawai`i, argued against anything other than an “ecosystem approach,” precluding special actions intended to address the imminent extinction of the Po`ouli.
Menard prepared a comparison of the actions and probable costs associated with each alternative listed in the draft EA. For example, the cost of capturing birds, breeding them, and releasing some of the offspring back into the wild, Menard estimated, would cost at least $357,200 — and probably much more. In addition, she noted that each of the alternatives identified entailed risks to the Po`ouli themselves.
Menard’s comments were echoed in those of Sheila Conant (reprinted elsewhere in this issue) and others.
According to Mike Buck, administrator of the state Division of Forestry and Wildlife, a decision on what to do with respect to the Po`ouli will probably be made sometime in November. Making that decision will be Buck and his boss, Mike Wilson, head of the Department of Land and Natural Resources, along with Robert Smith, head of the Pacific Islands office of the Fish and Wildlife Service, Buck said.
Even if the decision ends up being nothing more aggressive than habitat management, Buck says, the exercise of engaging the public in a debate will have had a valuable pedagogic purpose. “We have bad options in front of us,” Buck told Environment Hawai`i. “We need to reset our focus.” Instead of trying to save everything, and pouring limited resources into those species with the least likelihood of recovery, we should decide “which ones are we going to try to save.”
— Patricia Tummons
Volume 9, Number 5 November 1998
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