SAN DIEGO — A decades-long effort to save a critically endangered Hawaiian crow from extinction is taking a new strategy — relocating the birds to a different island than their historical home. And the San Diego Zoo Wildlife Alliance is playing a key role.
The ‘alala is native to the Big Island where earlier reintroductions were tried. In early November, however, wildlife experts released five of the birds on the island of Maui. The shift was made to avoid a Hawaiian hawk known as the ‘io that killed many of the released birds. The predator only lives on the Big Island.
The ‘alala is the only surviving native crow species in Hawaii. Its decline is blamed on a loss of habitat due to logging and deforestation, as well as predation and diseases brought by introduced species. A sharp dip in numbers prompted some birds to be brought into captivity in the 1970s, and the last ‘alala seen in the wild was in 2002.
The football-sized birds are about 18 inches long and a duller black color than crows in North America. They are considered highly intelligent and have been known to use sticks as tools to dig out insects.
In the wild, they promote forest growth by dispersing seeds of native plants. They are revered in Hawaiian culture as sacred spiritual family guardians and have loud, distinctive cries.
State and federal agencies, the San Diego Zoo Wildlife Alliance and other partners are working together to help the species. The zoo, which joined the effort in 2000, manages conservation breeding centers where the world’s only remaining ‘alala exist — one on the Big Island and one on Maui. (Two male birds also are displayed at a zoo in Hilo.)
The breeding program has boosted the number of birds from fewer than 20 in the late 1990s to a flock of 120 to 140, officials say.
“I would say our biggest challenge with the conservation breeding program is in this attempt to pivot to more parental care, having the parents rear their own chicks,” said Ron Swaisgood, director of recovery ecology for San Diego Zoo Wildlife Alliance. “We’ve had some successes, but all pairs won’t produce parent-reared chicks every year. We are still working on solutions to that issue.”
Before the November release, zoo specialists tried to prepare the selected birds — two females and three males — to be wary of predators and to forage for native fruits and insects. The five were raised as a group to form a strong social bond, which zoo officials said should help them depend on each other in the forest.
In early October, the ‘alala were transferred to a temporary field aviary on the slopes of Haleakala, and on Nov. 11 they were released into the Kipahulu Forest Reserve. It was the first release in five years.
“The birds are doing really well,” said Hanna Mounce, program manager for Maui Forest Bird Recovery Project, a conservation project affiliated with the University of Hawaii.
Conservation biologists from Mounce’s group fly by helicopter to the remote site each day to monitor the birds and resupply supplemental food including mealworms, dried crickets and avian pellets, as well as cut-up mice and fruit.
The day the birds were released, officials didn’t know what to expect.
“In past releases, sometimes certain birds just like bugger off right away and go long distances, maybe get scared by something and vanish,” Mounce said. “So we had all these people on the ground ready to track them kilometers away or to deal with some birds that aren’t coming back.”
Instead, she said, “they all just behaved so nicely” and stayed fairly close to the aviary and a nearby feeding station, where their weight is recorded when they land and their picture is taken.
There have been some issues. Two of the released birds came down with a case of suspected avian malaria, appearing lethargic and losing weight, but have since rebounded. Officials said the illness is common in the wild and wasn’t unexpected.
There also have been technology challenges. Each bird was fitted with a transmitter so they could be tracked, but they aren’t working, Mounce said. Biologists will probably switch to different transmitters but need time to figure out a solution. Researchers also want to come up with a way they can control the feeding station remotely.
“We can still see the birds every single day because they’re hanging out and vocal and not going too far,” Mounce said. But at some point, bad weather will ground the helicopter and researchers will need to rely on the transmitters.
It is unusual to translocate a species outside its known historical range, but officials were open to new ideas after the previous attempts on the Big Island failed. While some were killed by hawks, some were felled by diseases and other predators. Others died from exposure during winter storms or just disappeared.
“The translocation of ‘alala to Maui is a monumental step forward in conserving the species and a testament to the importance of partnership in reversing biodiversity loss,” Megan Owen, vice president of conservation science at San Diego Zoo Wildlife Alliance, said in a statement.
While any release plan comes with risk, keeping generation after generation of the birds in captivity isn’t a long-term answer, Mounce said, noting that only some of the females are laying fertile eggs. “It’s like every year that you wait for these wild releases, you potentially have less and less or (don’t) even have the opportunity to release,” she said.
According to U.S. Fish and Wildlife Service officials, 27 birds were released between 1993 and 1998. All but six died, and the survivors were recaptured and brought back into captivity.
On the next attempts, 30 birds were released between 2016 and 2019, with at least nine believed lost to hawks. Five survivors were recaptured.
Before the pilot program in Maui was approved, state and federal officials completed an environmental assessment comparing possible release sites and analyzing how the project might impact native birds and plants.
Swaisgood said planning is underway for releases on the Big Island, possibly in the Ka‘u Forest Reserve. That site is larger with more contiguous forest than the previous site, which might help because the hawks like to hunt at the edges of forests.
Other changes could be made in managing the birds as they mature. When they are young, the birds tend to hang out in a group and can warn each other about hawks and other predators, but as they get older they become more territorial and spread out.
Researchers could set up feeding stations in different locations to try to move birds so they’d have their own space and might be less distracted by territorial fighting.
“The first cohort (on the Big Island) coexisted for two years with ‘io. We saw them interact with ‘io. We saw them alarm call to ‘io,” Swaisgood said. “We are trying to do what we can to support that process for them to be able to coexist.”
It hasn’t been decided if the birds will remain on Maui after the pilot ends or if they’ll be recaptured. Regulatory agencies will help determine the next steps.
“With the release on Maui, we look forward to learning more about how the birds adjust to the forests of east Maui in the absence of ‘io (Hawaiian hawk). Given the ecological and cultural importance of ‘alala, this translocation on Maui and the lessons learned will inform and guide us for future conservation efforts for ‘alala,” Chelsie Javar-Salas, lead biologist for the Pacific Islands Fish and Wildlife Office, said in an email.
“The overarching goal is to see ‘alala thrive in the wild so that they can one day be rereleased on Hawaii Island. However, our main focus at this time is making sure the five ‘alala remain healthy and safe as they adjust to being in the wild for the first time.”
For now, researchers delight in seeing the birds flying high above the canopies of koa trees and listening to their distinctive cries as work continues helping the species.
“These guys have been extinct in the wild for a long time, and I’m of the mind that even if we are feeding them and supporting them and giving them shelter with an aviary in the field, that is a lot better than them being in cages in a facility,” Mounce said.
