Hawaiian crow is ‘very smart’ – but hawks keep attacking it


Plans to repopulate Hawaii’s forests with its “highly intelligent” crows have been upended in part by its natural predator, the Hawaiian hawk. Now scientists are tracking the falcon in order to save the corvids.

(Illustration by Emily Sabens/The Washington Post; Eric J. Franke for The Washington Post; iStock)


FERN ACRES, Hawaii — Amy Durham wrapped the straps under the wing, over the wing, under the other wing, over the other wing, ensuring the backpack-like device stayed comfortably attached to the Hawaiian falcon for many months.

“This might be your best work yet,” said Diego Johnson, one of his colleagues holding the straps to the chocolate-colored falcon’s chest as Durham secured a lightweight GPS transmitter to his back.

These San Diego Zoo researchers scour the mountainous jungles of Hawaii’s Big Island, not just to understand the ‘io, one of the state’s only endangered birds of prey. It’s also crucial to restoring an even more endangered species of bird – the ‘alalā, or Hawaiian crow.

Known for its problem-solving abilities, the Hawaiian crow is one of the most remarkable bird species in the world. The ‘alalā, whose name means “to shout” in the local language, is one of the only birds in the world known to naturally use – and even make – its own tools.

Again this distinctive raven that many describe as “very intelligent” was extinct in the wild for two decades, with only about 120 alive in human care today.

So far, plans to repopulate Hawaii’s forests with its native crows have been partly canceled by the ‘io. Hawks are the natural predator of crows and came after corvids in previous reintroduction efforts.

By tracking the hawks, scientists from the San Diego Zoo Wildlife Alliance and the Hawaii Department of Lands and Natural Resources are trying to determine where it’s safest to reintroduce the crows so they can once again thrive in the wild. . At the heart of their research is a puzzle: how to protect two rare birds when one keeps attacking the other?

“They have co-existed for many years,” said Bryce Masuda, the zoo’s conservation program manager. Now, his team is trying to make these two species of birds, found nowhere else on Earth, coexist again.

Bringing back a “family god”

Ever since people set foot in the Hawaiian archipelago, humans have been captivated by the crows of the islands.

Its shiny black feathers adorned native Hawaiian dresses. Its imposing beak and piercing eyes have led some families to consider ‘alalā as the manifestation of an ‘aumakua, or “family god” who watches over them.

When Captain James Cook arrived in Hawaii in 1778, many crow kills stalked the volcanic hills of the islands.

Over the centuries, a variety of factors—diseases, destruction of forests for agriculture and cattle ranching, and predation by cats and other non-native animals—have conspired to drive down the crow population.

In 1992, there were only 13 ‘alalā in the forests of Hawaii. The last savages were spotted a decade later. The only known ‘alalā so far lives in two breeding centers run by the San Diego Zoo on the Big Island and Maui.

A photo of one of the survivors caught the attention of Christian Rutz, a behavioral ecologist at the University of St. Andrews in Scotland.

For more than a decade he had studied another species of corvid called the New Caledonian crow. Without any training, chicks from New Caledonia, a French territory in the South Pacific, pick up sticks to collect the larvae in the crevices. At the time, no other crow was known to naturally use tools.

But Rutz suspected there were others. When he saw the Hawaiian crow’s straight beak and forward-facing eyes — perfect features for holding and handling twigs — he phoned the San Diego Zoo Bird Conservation Center.

An official told him that Hawaiian crows always fly around with sticks in their beaks. Rutz was stunned. “I pretty much booked myself for the next flight to Hawaii,” he said.


Hawaiian crows at the Keauhou Bird Conservation Center in Hawaii use sticks as tools to retrieve food from small holes and crevices. (Video: San Diego Global Zoo)

In a paper published in the journal Nature in 2016 and subsequent research, Rutz, Masuda and others showed that Hawaiian crows do more than pick up sticks to extract bits of food from logs.

Crows have also made their own tools – shortening sticks or stripping them of bark to make them fit better in tight, grub-filled nooks. “They will fashion the right tool for the right job,” Durham said.

Living on isolated islands with little competition for insects, both crow species likely developed their dexterity with twigs independently of each other.

“They were just incredibly smooth,” Rutz said.

“No other bird looks like it”

At the Maui Zoo’s Bird Conservation Center, a pair of ‘alalā awaiting reintroduction jumped from roost to roost one recent morning in their enclosures, landing with a loud thump. The birds flexed their tufts and ogled their human trainers with large, expressive eyes.

“There is no other bird like him,” Masuda said.

As of 2016, biologists have attempted to bring ‘alalā back into the wild. Yet, of the 30 freed, 25 died or disappeared. The other five were taken over.

“There’s not a clear reason why the birds didn’t thrive,” Masuda said. Some disappeared without a trace while others succumbed to an untimely storm.

And then there was the falcon. Before releasing them, biologists trained the captive ‘alalā to avoid ‘io. In the wild, some of the released crows have protected themselves by ganging up on aggressive ‘io. But other crows were preceded by hawks.

To tag the highly territorial hawks with GPS trackers in their renewed effort to reintroduce the crow, the San Diego Zoo team blasted the raptor’s namesake howl “eeeh-oh” from a portable speaker.

Once a hawk was lured to a nearby perch, the team placed a ring-shaped metal cage with a mouse inside. Thinking he had a free meal, a hawk swooped in – and caught its talons in plastic loops atop the trap.

“It’s actually an ancient falconry technique,” said Johnson, a zoo biologist who helped design the device.

After capturing the chocolate-colored male in December, Johnson stretched out each wing to measure the length, turned the bird around to look at its tail plumage and gently felt the muscle on the sternum.

“It’s a very healthy bird,” he concluded.

On Johnson’s phone is a map lit up with blue, green and magenta dots – each the location of some of the other 41 previously labeled “io”. The gaps show areas where they haven’t caught a hawk yet. Around the ankle of the most recently captured falcon, the team placed a band bearing the number “42”.

Lightweight solar-powered transmitters on each bird’s back transmit latitude, longitude, altitude and other data to nearby cell towers several times a day. The contraption is fixed with a single point so that it falls off harmlessly in about two years. At a cost of over $1,000 a unit, someone will eventually have to pick up each transmitter.

“I can literally sit in the comfort of my air-conditioned office in San Diego and remotely download the location data of every bird,” said zoo ecologist James Sheppard. “It’s fair to say we’re in the golden age of wildlife tracking.”

Research has already revealed that some ‘io have much larger territories than others. One idea to reduce the risk of an ‘alalā encountering an ‘io in the wild is to place crows near hawks with plenty of ground to cover.

But Masuda, the conservation program manager, warned: “If we knew what they need to thrive, we would have released them a long time ago.

With his backpack secured, the falcon got a ride from central headquarters to be released where he was first captured – and fill another spot on the scientists’ map.

As Durham prepared to let go, “42” looked at her with his saucer eyes. She raised her hand to shift the bird’s attention to a nearby grove of trees – and let go.

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