Restoring 'alala to the Hawaiian forest.
For the past 15 years, the Hawaiian crow or 'alala (Corvus hawaiiensis) has existed only in captivity. Soon, however, the raucous cry of this medium-sized crow will ring out in the Hawaiian forest once again. Those involved in the effort to recover the species look forward to returning the bird to the wild later this year--a tremendous milestone resulting from years of dedicated efforts by an array of partners to breed the species in captivity, remove threats, and restore tens of thousands of acres of habitat.'Alala is a social bird that is endemic to the island of Hawai'i. Formerly common in semi-dry 'Ohi'a (Metrosideros polymorpha) forest on the south and west slopes of the Mauna Loa and Hualalai volcanos, 'alala began to steadily decline in the late 19th Century. While 'alala is highly regarded in Hawaiian culture-- traditionally kept as a ceremonial pet and considered by some families as an "aumakua," or family guardian spirit--fruit and coffee farmers saw the birds as a nuisance. Many 'alala were reportedly shot on private farmlands between 1890 and 1930 because they were believed to raid crops. Despite legal protection in 1931, human persecution continued for several decades. This, in addition to habitat loss, introduced mammalian predators, and disease caused the species to dwindle until only a single, small population remained on Mauna Loa.
In response to rapid population decline and range contraction, the Hawai'i Department of Land and Natural Resources' Division of Forestry and Wildlife (DOFAW) brought some 'alala into captivity for breeding in the 1970s. In the 1990s, 21 captive-reared 'alala were introduced to the west slope of Mauna Loa with hopes that the young birds would breed and bolster the wild population. While this first reintroduction effort was unsuccessful, partners gained a better understanding of the species' specific habitat needs and its vulnerabilities to predation and disease.
The 'alala requires native 'ohi'a forest with a thick understory of native plants as food and for protection from the endangered 'io or Hawaiian hawk (Buteo solitaries), which preys on the 'alala. Years of grazing and logging activities left the Mauna Loa reintroduction site for the first release with a thin, open understory that exposed 'alala to predation by 'io. The forest also harbored feral cats carrying toxoplasmosis, a disease that was identified as having caused the death of at least three of the reintroduced 'alala.
The captive 'alala population has steadily grown from fewer than 20 individuals in the 1990s to more than 115 birds today. While the captive breeding program has been successful, the species continued to decline in the wild. A lone wild pair of 'alala was last seen in 2002. Reports of the bird since then have been unconfirmed, and the species is now considered extinct in the wild.
The entire world population of 'alala now exists at two forest bird captive breeding centers--the Keauhou Bird Conservation Center (KBCC) in Hawai'i, the Maui Bird Conservation Center (MBCC), and one 'alala is at the San Diego Zoo's Safari Park because it is imprinted on humans and researchers are attempting to collect sperm for artificial insemination. The KBCC and MBCC are managed by the San Diego Zoo Global Institute for Conservation Research (SDZGICR), with funding from the U.S. Fish and Wildlife Service (Service), DOFAW, and private donations.
The restoration of native habitat and reintroduction of 'alala to its native habitat are key steps for recovery. The Service--with assistance from the 'Alala Recovery Team, 'Alala Working Group, and other partners--evaluated potential release sites for the species on the island of Hawai'i and determined that Pu'u Maka'ala Natural Area Reserve on the southeast slope of Mauna Loa provided the most suitable habitat. Pu'u Maka'ala is managed by the Natural Areas Reserve System (NARS) under the Hawai'i Department of Land and Natural Resources.
Forest management has included the removal of non-native pigs, goats, sheep, and cattle, and the installation of fencing to prevent these animals from eating native forest plants. Partners have also removed non-native predators including mongoose, rats, and feral cats from the properties. These efforts have resulted in the regrowth of forest understory that will provide food and cover for 'alala from 'io. Control of introduced mammals before and during restoration will reduce the risk of 'alala succumbing to predation by small mammals and to sickness from toxoplasmosis. Reintroduction of 'alala at Pu'u Maka'ala is planned for the fall of 2016. Young 'alala hatched and reared at the KBCC and MBCC will be transported to Pu'u Maka'ala and held in a large flight conditioning aviary for one to two months, where they will be fed and cared for as they acclimate to their new home. 'Alala will receive training to recognize 'io as predators and to take evasive action like seeking shelter in dense understory vegetation. 'Alala will be released either from the conditioning aviary or smaller release aviaries throughout Pu'u Maka'ala, and will be monitored closely to determine their health and behavior. After release, biologists will provide food and veterinary care as needed until the birds are completely independent and able to thrive on their own.
Partners have identified other suitable restoration areas throughout the species' former range, including nearby Hawai'i Volcanoes National Park and the State of Hawai'i Ka'u Forest Reserve. These sites are also being actively managed in preparation for future releases. Kamehameha Schools, the largest private landowner on the island of Hawai'i, will also begin voluntarily managing its Kilauea Forest under a Safe Harbor Agreement with DOFAW and the Service. The Kilauea Forest property neighbors Pu'u Maka'ala and is likely to be used by 'alala in the future.
Partners are hopeful that 'alala will thrive in their new home in the wild, providing a critical step toward the species' recovery.
Donna Ball, Megan Laut, and Jay Nelson are biologists with the Service's Pacific Islands Fish and Wildlife Office and can be reached at 808-792-9400. Iwikau'ikaua Joaquin, the Kamehameha Schools Outreach Coordinator, can be reached at ijoaquin@hawaii.edu. Lea Ka'aha'aina, the 'Alala Project Outreach Coordinator with the Hawai'i Division of Forestry and Wildlife, and can be reached at 808-9744221.
Caption: The voice of the vocal 'alala is compelling and awe inspiring, comprising a variety of distinctive growls, whoops, cries, grunts, chortles, and screams. By far the loudest bird in the Hawaiian forest, at least 34 different 'alala calls have been recorded in the wild. Credit: Jack Jeffrey
Caption: Hand-reared 'alala nestlings at Keauhou Bird Conservation Center. Credit: Natalie Staples
Caption: Young 'alala familiarizing themselves with native food (pilo). An omnivore, the diet of the 'alala includes more than 30 species of native fruits. The 'alala also eats insects, as well as eggs and nestlings of other birds, nectar, flowers, and dead animals. Credit: Jack Jeffrey
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| Author: | Ball, Donna; Joaquin, Iwikau'ikaua; Ka'aha'aina, Lea; Laut, Megan; Nelson, Jay |
|---|---|
| Publication: | Endangered Species Bulletin |
| Geographic Code: | 1U9HI |
| Date: | Mar 22, 2016 |
| Words: | 1126 |
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