Last month, the Natural Area Reserves System Commission unanimously approved a one-year special use permit to the San Diego Zoo for the much-anticipated release this year of the endangered native Hawaiian crow, also known as the ‘alala. The release follows decades of recovery efforts by the state and private contractors, which has cost millions of dollars and will likely cost millions more. With so much invested and so much at stake, the release of the birds into the wild will involve much more than simply walking into the forest and freeing them from a cage.
The zoo’s planned management and monitoring of the birds released into the Pu‘u Maka‘ala Natural Area Reserve will include the installation of a greenhouse- style aviary, mobile living quarters able to house up to five people overnight, a mobile office, 15-foot-tall telemetry towers around the release site to help track the birds’ movements, feeding stations, capture sites, and artificial nests known as hack towers. The office and living quarters will be placed near the Kulani Correctional Facility at a previously cleared site.
Once built, the aviary will start housing a group of young birds in July. The zoo plans to release them in September when they are about three to four months old, and release a second group in November. The zoo has decided to release young birds because they may adapt to new surroundings more easily than older birds that have already established a territory at the Keauhou Bird Conservation Center near Volcano, where the birds are reared.
All birds, 12 in total this year, will be outfitted with GPS and VHF transmitters. Over the next five years, the zoo hopes to release 12 birds a year. If any die, zoo staff will recover them to determine cause of death; sick or injured birds may be removed from the wild, the permit application states.
The last time ‘alala were reintroduced into the wild, in the 1990s, several factors contributed to their failure to thrive: Fitted with backpack radio transmitters, they were released into pasture lands in South Kona, where they may have been easy prey for predatory birds such as the native Hawaiian hawk (also known as ‘io) or, according to Department of Land and Natural Resources wildlife biologist Fern Duvall, barn owls, which are known to eat crows. The ‘alala were also released into an area where they were perhaps more apt to be exposed to Toxoplasma gondii, a parasite carried and spread by feral cats. Of the 27 birds released, all but six of them died and the remaining birds were recaptured.
This time around, the birds will be taught predator avoidance — by, for example, showing the birds models of hawks and sounding alarm calls — and will be released in an ungulate-free reserve that has rich, protective forest cover and fewer ‘io than the Kona release site. According to Jackie Gaudioso-Levita of the Department of Land and Natural Resources’ Division of Forestry and Wildlife, only five ‘io were found during a survey of 19 stations along fence lines at Pu‘u Maka‘ala — far fewer than the dozens sighted in South Kona, where in 2006 to 2007 they were suspected of killing a number of released ‘alala.
Protecting the ‘alala from toxoplasmosis, which afflicted several of the birds that had been released in the 1990s, is one of the release team’s biggest concerns and will be difficult to achieve, says DOFAW wildlife biologist John Vetter. Toxoplasma gondii cysts are commonly found in the feces of cats, which are present within the Pu‘u Maka‘ala NAR, and can persist in the environment for years.
“Feral cats can inhabit even the wettest forest,” Duvall says. Vetter adds that the release team doesn’t expect that Toxoplasma gondii prevalence in the reserve is any lower than at the old release site.
The reserve’s management plan and the ‘alala release plan both call for removing small predatory mammals (e.g., rats, mongooses, and cats), which are also vectors for toxoplasmosis. In addition to trying to reduce the prevalence of the cysts in the birds’ immediate environment, Vetter says managers are also hoping that with a dense forest to forage in, the birds won’t want to “go to ground as much.” If necessary, the birds may be even be trained to avoid cat feces before they’re released, according to the plan.
Although ‘alala are not known to have inhabited the Kulani area of Pu‘u Maka‘ala, perhaps because it was too rainy, a NARS report states that it was selected as the best release site “due to ongoing management of habitat and predator control.” At the NARS Commission’s meeting last month, Bryce Masuda of the San Diego Zoo acknowledged that the ‘alala is known primarily from the Kona side, but added that Pu‘u Maka‘ala is on the border of its known range and the hope is that the birds will eventually expand into their former range.
At the commission’s meeting, Duvall suggested that it might be more prudent to build a release site on forest reserve lands in the ‘alala’s known home range rather than in a highly protected NAR. Duvall, who headed efforts in the 1980s to rear ‘alala in captivity on Maui, questioned whether compromising the NAR was justified.
Hawai‘i NARS manager Nick Agorastos replied that he had found a spot within the NAR — an old water tank site — where infrastructure could be built without compromising the forested area, according to draft minutes of the meeting. Gaudioso- Levita also pointed out that the forest reserves outside the NAR may be affected by Rapid ‘Ohi‘a Death (ROD), so managers “don’t want to go there.” (ROD is a fungal disease that has killed thousands of acres of ‘ohi‘a trees on Hawai‘i island.)
In the end, the commission chose to limit the permit to one year so that conditions can more easily be revisited and adjusted in following years, if necessary. “There have been years of talking and not doing; we are at a point where we need to take risks and not be paralyzed with further inactivity while trying to protect the rarest of the rare,” commission member Sheila Conant said.
Volume 26, Number 11 May 2016