A Very Sensitive Crow

By Bill Chaisson
Of a Feather
You can’t really read a book about extinction without mention of Hawaii. The bird life of the islands includes one spectacular adaptive radiation, the honeycreepers, which is on par with the finches of the Galapagos. But the archipelago also features birds like the Hawaiian goose (nene) and the Hawaiian hawk (‘io), singular colonists that did not diversify like the honeycreepers.

I recently finished Elizabeth Kolbert’s The Sixth Extinction, where I was introduced to the Hawaiian crow or ʻalalā. I don’t think of crows as particularly strong fliers, so I was surprised to discover they had reached a location 2,500 miles from California. Their relationship to mainland corvids is still not completely understood, but they seem more closely related to the ravens than the crows. This makes sense, as ravens are stronger fliers.

The ʻalalā is critically endangered; there are no wild crows and a small captive population is not breeding very rapidly. In a somewhat prurient passage in the book Kolbert describes the difficulties of getting a Hawaiian crow aroused. The sexes apparently do not get along well in captivity, so getting the males to be “interested” without fisticuffs breaking out takes some doing.

Like corvids everywhere, they tame easily, and their intelligence attracts human admiration. Hawaiians call them “he manu leo nui,” the bird with the big voice, and they are associated with dark magic (as crows and ravens are most everywhere). According to a website set up to restore the species, their name has several associations. It is also used to describe “a chant used to further project one’s voice,” the messenger who in battle relays the commands of the chief to his warriors, and (paradoxically) the cry of a baby.

While the Hawaiians collected the feathers of the bird for ceremonial purposes, they did not eat it and it was accorded a measure of protection and often tamed. “By returning the ʻalalā to the wild,” the website states, “we are welcoming home a family member that has been away for a long time and fulfilling our reciprocal responsibilities as stewards and ancestors of this land.”

The crows of Hawaii radiated more than the hawk and less than the honeycreepers. Five species have been discovered, four of them known only from fossil remains and only two of those have been described and given names. While the (barely) extant species is Corvus hawaiiensis, two of the extinct taxa are called C. viriosus and C. impluviatus. It is not known whether this group represents a radiation from a single colonization or separate arrivals. C. viriosus had a longer bill than ʻalalā and the bill of C. impluviatus was modified for hammering. The other two species are known only from scattered bones found in lava tubes.

In post-European arrival times theʻalalā was found primarily in the southwestern and southeastern portions of the “Big Island” in forests at elevations between 730 and 1,730 meters (2,400 to 5,700 feet). These dry and seasonally wet forests have been fragmented or eliminated by grazing and wildfire, and the understory plants have been decimated by foraging feral pigs and goats. While most corvids adapt rather well to human incursion, the Hawaiian crow population plummeted through the 20th century.

It has been noted in the wake of the recent conflagration in western Maui that fire is not part of the ecosystem dynamics in the Hawaiian archipelago. Therefore, the native species—both plants and animals—are not adapted to it. When it does occur, the burned areas are revegetated and populated by species that have been introduced from places that have a natural fire cycle (like California).

In addition to habitat loss, feral mongoose, cats, and rats eat ʻalalā eggs and chicks. As per the state website: “Like other native forest birds, ‘alalā can get sick from avian malaria carried by mosquitoes, as well as from toxoplasmosis carried by feral cats and rats. Pox virus, transmitted by mosquitoes or through contact, can cause debilitating lesions.”

The reintroduction of ʻalalā to the wild is initially being attempted at Puʻu Makaʻala Natural Area Reserve in southeastern Hawaii because the area has been managed for many years to exclude grazing animals, restore native plant species, and therefore recreate both a food supply and a habitat for the native crow that allows it to hide from predation by the Hawaiian hawk.

The alalā is an odd-looking crow. Its bill is large and heavy, almost like that of a raven, but its tail is fan-shaped (unlike the raven’s wedge). The legs are long and strong and allow it to cling to vertical surfaces and to forage hanging upside down like a chickadee. There are long bristly feathers at the base of the bill and on the upper part of the throat, giving it a scruffy, unshaven appearance.

It is not unusual for island species to be bigger than related mainland species and the Hawaiian crow, at 19-20 inches long, averages slightly larger than the American crow. It tends not to be as black, often described as chocolate brown, especially on the wings. And the wings are shorter and more rounded than those of its mainland relatives.

Like most corvids, the ʻalalā eats almost anything. As such it was an important disseminator of plant seeds and its disappearance in the wild means that a vector for spreading many native species is now missing. Some plant species took coevolution to the point where their seeds had to be partially digested in the digestive tract of the crow before they would germinate.

The species was given protection by the Hawaii government after 1931 and declared endangered by the federal government in 1967. Reintroductions have been attempted on Hawaii between 2016 and 2020, but there has been no successful nesting. There has been discussion about releasing them on Maui where Hawaiian hawks do not occur. But they might be rethinking that now.

– Bill Chaisson has been a birdwatcher for over 50 years. He lives and works in Wilmot.