This time, they were ready.
When the state released five male, captive-reared endangered Hawaiian crows (`alala) into the Pu`u Maka`ala Natural Area Reserve on December 14, 2016, managers found out the hard way that some of them weren’t ready to fend off attacks from native Hawaiian hawks (`io) or otherwise survive on their own.
In 2002, the species had disappeared from the wild and survived only at captive rearing facilities in Keauhou, Hawai`i and Olinda, Maui, run by the San Diego Zoo Global’s (SDZG) Hawai`i Endangered Bird Conservation Program.
Despite extensive preparation, within two weeks of their celebrated and long-awaited release, three of the released birds were dead. Two were killed by `io, while another simply failed to thrive. Staff with the `Alala Project — a partnership that includes the state Division of Forestry and Wildlife, the U.S. Fish and Wildlife Service and SDZG — recaptured the remaining two and went back to the drawing board.
At the annual Hawai`i Conservation Conference held in Waikiki this past July, project members detailed how they strengthened preparations for the next cohort and proudly proclaimed that all 11 birds (four females and seven males) released in September and October 2017 were still alive and well nearly a year later. What’s more, the birds have been seen banding together to fend off `io attacks, foraging broadly, and perhaps even pairing up, they said.
“We went back to the basics,” said Alison Greggor, a post-doctoral research associate with SDZG’s Hawai‘i Endangered Bird Conservation Program of her team’s approach following the recapture of the two survivors of the 2016 release. The team re-evaluated what the captive-raised `alala needed to know before entering the wild. “Captive environments lack foraging challenges, exposure to predators, natural social groups. We went through and tried to address each one of these,” she said.
`Alala have large brains for their body size and a long juvenile development period. So compared to other species, `alala have a lot they need to learn because they don’t have as much ingrained behavior, she said.
“A juvenile needs to see a predator while hearing a danger call of an adult,” she said. Her team experimented with a variety of proxies to see which ones the `alala found the most convincing. The team employed plastic `io or stuffed ones to “fly” over the aviary, while putting a dead corvid under their feet. Ultimately, a combination of different techniques was used, although she said the birds responded most strongly to a live hawk borrowed from the Panaewa Zoo.
In addition to finding the most effective version of a predator, the team needed to pair that audible with danger cues. The team collected a variety of vocalizations from the captive flock, including distress calls the birds make when they think they’re injured, she said.
With the visuals and the alarm calls combined, the team essentially created a vivid theater production for the `alala.
“We want to make sure we’re actually creating fear,” she said.
While the predator play proceeded, the team documented the kinds and amount of fear behaviors the `alala exhibited, whether it was making alarm calls or pace flying in the aviary. “Per minute, we were getting 100 fear behaviors in cohorts. We even had some birds come up and mob the `io,” she said, adding that those birds included the ones released in 2016.
With regard to foraging, she noted that adults of species of the crow family are known to be wary of novel food types and, therefore, may need to be exposed to potential food sources before that wariness takes hold. “Before they are released, they have to prove they are competent in foraging from these several types [of food],” she said.
Pre-release, the team also documented the birds’ social networks, which ones interacted best and which ones were aggressive toward one another. Using that information, the team was able to ensure they released a socially intact cohort. “This allowed us to feel more confident that when we opened those doors they weren’t going to scatter,” she said.
“Training can be effective, but you need to evaluate whether all individuals are interacting with the training,” she said, noting that more than 30 percent of animal reintroductions report difficulties related to animal behavior, yet only five percent of all reintroduction papers between 1990 and 2005 mentioned behavior.
“I’m happy we do have 11 birds all flying and thriving,” she said.
She explained that training for the birds released in 2016 included some of the same elements in the current program, but was less rigorous and lacked the same level of evaluation. “The biggest change was making it a strategic plan moving forward,” she said.
Greggor was asked about how the `alala might respond to predator training using an animal absent from its evolutionary background, such as a small mammal. Feral cats, rats, and mongooses are found throughout the reserve and pose a real threat to the `alala and/or its eggs, if or when the birds start breeding in the wild. Rats and cats are also hosts of the parasite Toxoplasma gondii, which has infected and killed `alala in the past. The state has conducted extensive predator trapping in the release area — removing 200 rats, 105 mongooses, and 13 cats since 2016 — but the invasive mammals persist.
Greggor responded that she wasn’t aware of any cognitive biases the birds might have to such training. “We’re working on it. … What are the limits of this training? It’s still being figured out,” she said.
Joshua Pang-Ching, research coordinator for the Hawai‘i Endangered Bird Conservation Program, detailed how the birds have done, post-training.
Before they were released, the birds were transferred to a custom-built aviary within the reserve where they could practice flying and build their muscles. They were also banded (orange for the males, white for the females) and fitted with tracking harnesses.
“Now that the birds are out, the biggest portion of the work is tracking, making sure they’re healthy,” he said, adding that managers follow and observe the birds at least once a day, taking note of their overall health, location, movements, behavior, and social interactions. A spring scale/feeder set out in the forest also allows the team to monitor the birds’ weight.
Pang-Ching reported that the birds have improved their overall flight competency, maneuvering with greater confidence. They’ve been tracked doing 700-meter jaunts and exploring new foraging habitat, he said, adding that his team is hoping to see the birds start to establish territories and select breeding locations.
“The furthest flight that we know of was 2,200 meters away from the aviary. They’re not moving too far, but they are moving pretty far for us to keep track of ‘em,” he said.
On two occasions, managers have seen multiple `alala chasing and scuffling with `io, with feathers flying and alarm calls ringing through the trees. “How many other interactions are going on? … I’d like to say [the predator training] was a success. The birds are surviving where there’s two `io almost every day,” he said.
While the birds have often been seen eating the wild foods they’re supposed to, pecking through `ohi`a flowers, looking for insects in bark and leaf litter, pulling out worms from dead logs, and “just having a great time,” Pang-Ching said, they still receive supplemental food.
Managers provide papaya, melons, food pellets, peas, and carrots to help the birds overcome any diet obstacles, he said, adding that peas and carrots are the birds’ least favorite. The food is set out before light and any leftovers are removed after dark. However, Pang-Ching said his team is going to try to eventually wean the birds off supplemental food.
Another promising development: managers believe a male and a female seen hanging out together may be a potential mating pair. “Next year is going to be pretty exciting, coming to the breeding season, seeing what those two do,” he said.
Before then, he said the team plans to release another group of birds. A site elsewhere in the NAR has been chosen and a new pre-release aviary is being built.
He stressed that re-establishing a thriving population of `alala in the wild will be a long process, reminding the audience that the endangered Hawaiian goose, or nene, is a good example of what to expect. In 1960, there were an estimated 30 nene left in Hawai`i. But with captive breeding, predator control, and habitat protection, “[t]oday, more than 2,800 nene live across all of the Hawaiian Islands,” states a webpage for Island Conservation, a company that specializes in removing invasive species from islands to aid protected species. The U.S. Fish and Wildlife Service has proposed that nene be downlisted from endangered to threatened.
“It took a long time to get the [nene] population back,” Pang-Ching said.
For now, he’s enjoying the success made by the `Alala Project so far. He recalled how he used to be jealous of veteran U.S. Geological Survey wildlife biologist Paul Banko, who spent years working to save the `alala and was able to see and hear the birds in Hawaiian forests before they went extinct in the wild. Now, Pang-Ching said, “I’m jealous of myself. I get to see it and talk about it.”
“Their calls have become part of the beautiful [dawn] chorus. … Probably the sound is my favorite thing,” he said.
(For more background, read, “NARS Commission Grants Permit For ‘Alala Release at Pu‘u Maka’ala,’ from our May 2016 issue. Visit @alalaproject on Instagram to track developments.)
— Teresa Dawson