Crows (2 page)

Crow lovers one and all, these busy people found time not only to answer my many questions but also, in several cases, to review relevant portions of the text. I am grateful for their collaboration and, most of all, for their crow-like fascination with the world around them.

O
N AN ISLAND in the South Pacific Ocean, somewhere west of Fiji, a sleek black crow is poking around in the greenery of a sun-streaked rain forest. With its senses sharply focused on the search for food, the bird hops from branch to branch and from plant to plant, jabbing its stout beak into the bases of palm leaves and cocking its head to inspect crannies in the bark. Insects are hidden in there—juicy centipedes, weevils, and grubs—but many of them are out of reach, buried deep in the vegetation or curled up at the bottom of wormholes drilled into the tree trunks.

An ordinary bird might be stymied by these difficulties, but not our crow. Without hesitation, it flies to a nearby tree and picks up a twig that it had left there a few minutes earlier. At first glance, the stick doesn’t look particularly special: it’s just a sprig from a native deciduous tree,
Elaeocarpus dognyensis,
that has been stripped of leaves and bark. On closer examination, however, you can see that the stump-end of the twig, where the crow snapped it off the branch, has been nibbled to form a tiny hook. And watch what the crow can do with it! Grasping the twig in its bill, the bird flies directly back to its foraging site, positions the stick so that one end is braced against the side of its head, and then deftly inserts the implement, hook first, into the crevice. With a few quick flicks of its beak, the bird works the twig back and forth, then pulls it out, with a tasty insect squirming on the end of it. Crow, the Tool User, in action.

This techno-savvy bird is a New Caledonian crow,
Corvus moneduloides,
a species found only on the remote islands of Grande Terre and Maré in Melanesia. (New Caledonia is a French colony about a thousand miles northeast of Brisbane.) When the bird’s sophisticated tool behavior was first described by biologist Gavin Hunt of the University of Auckland, New Zealand, in 1996, the news made headlines in the prestigious journal
Nature
and raised a hitherto little-known species to celebrity status. And as the spotlight fell on the New Caledonian crow, the glow of scientific fascination quickly spilled out to include all the other species of crows around the world.

They’re out there in our own backyards, spying on us from lampposts, stealing food from the dog, and shattering the early morning with their loud, steel-edged caws. If one species of crows routinely makes and uses tools—a behavior so remarkable that it was until recently thought to be uniquely human—then what might the rest of those swaggering, black-clad wise guys be up to?

There are about forty-five species of crow in the world (a couple more by some estimations, a couple fewer by others, depending on whether local varieties are split into separate entities or lumped together). Although they are known by a variety of common names, including ravens, jackdaws, and rooks, all are members of the genus
Corvus,
or crow, and all are variations on a theme, with their glossy black (or sometimes black-and-white) plumage, their raucous voices, and their seemingly endless capacity to fly out of the frame of our expectations and surprise us. They are medium-sized or largish birds—the smallest, the European jackdaw,
Corvus monedula,
is about the size of a large cockatiel—with sturdy bills, strong feet, and venturing minds that are formed for exploration and discovery. The burliest member of the crow tribe, the common raven,
Corvus corax,
is as big and brassy as a macaw and just as impressive, with its liquid calls, rustling cape of feathers, and keen alertness. (One of the most widespread birds in the world, the common raven is found throughout the Northern Hemisphere, from Europe and North Africa east through Asia and across the northern reaches of the New World.)

In between these extremes in size lie the other members of the global crow congregation, including a dozen species found exclusively in Europe and Asia—among them the gregarious rook,
Corvus frugilegus,
a familiar bird of farmland across both continents, the pied hooded crow,
Corvis cornix,
and its all-black cousin, the carrion crow,
Corvus corone.
Another eight or nine species are native to Africa, and five or six are found only in Australia: the Australian raven,
Corvus coronoides,
for example, with its mournful, fading wail, and the only-slightly-smaller little crow,
Corvus bennetti,
which is famous for its exuberant aerial displays. Yet another dozen-plus species are unique to islands in the South Pacific and the West Indies, from New Caledonia and New Guinea to Jamaica.

Strangely, there are no crows at all in South or Central America, where
los observadores de pájaros
have to be content with a profusion of brightly colored jays and magpies, the crows’ closest relatives. (Crows, magpies, and jays belong to different genera, or kinship groupings, within the larger family connection of the tribe Corvini.) North America is blessed with four species all its own: the sociable northwestern crow,
Corvus caurinus,
of the west coast; the glossy fish crow,
Corvus ossifragus,
of the eastern seaboard, with its distinctive nasal caw; the heavyset Chihuahuan raven,
Corvus cryptoleucus,
of northern Mexico
and the southwestern United States; and the lively American crow,
Corvus brachyrhynchos,
which is seen and heard almost everywhere else. Rounding out the clangorous chorus, in North America as elsewhere in the Northern Hemisphere, is the common raven, which drifts over gloomy forests and bleak tundra from sea to sea to sea, uttering its sonorous commentary.