Creature Feature: The Common Raven is an Uncommonly Intelligent Bird
When bird brains were being passed out, the common raven (Corvus corax), one of ten raven species worldwide, must have received an extra measure or two. There is, in any event, no smarter bird species in the national parks and damn few anywhere else.
As students of Native American mythology can attest, the raven's intelligence is quite literally legendary. Raven, like Coyote, is the embodiment of craftiness and trickery, and there is more to this than myth. Empirical studies confirm that the bird's reputation for braininess is well deserved. In the lab, scientists are challenged to invent ever more complicated tasks (including tool use) for what some call the "Einstein of the bird family." In the field, researchers have documented a similarly impressive array of competencies.
Ravens are awesomely good mimics, sometimes using this skill not just to amuse themselves, but to deceive or confuse, as the situation may demand. Their communication system is intricate, employing not only body language, but also a sophisticated system of vocalizations that has at least 30 different patterns (including local variants) for purposes such as hailing, warning, threatening, taunting, and cheering. The raven's curiosity, ingenuity, problem solving ability, and playfulness all reveal an intellect of a caliber that we seldom associate with birds -- or with most other animals, for that matter.
Unfortunately, the same keen intellect, curiosity, and playfulness that makes ravens interesting and amusing also makes them troublesome. Because ravens hanging around farmsteads quickly learn how gate latches work, they sometimes open gates to livestock pens. Ravens frequenting picnic areas, campgrounds, parking lots, trailheads, hunt clubs, and similar places learn how to get into an impressive variety of food containers. A pair of ravens at Scottys Castle in Death Valley National Park, for example, know how to open the zippers on motorcycle saddlebags containing snacks. At the Squaw Flat Campground in Canyonlands National Park, ravens are generalists, forcing officials to prominently post signs that read:
Ravens have become very adept at obtaining human food in the campground. They are clever, curious, and persistent. They can easily get into food packages, cardboard boxes, styrofoam coolers, and soft-sided coolers. Ravens can even pry coolers open with their beaks and unzip packs! Stow all food, trash, paper products, and body care items in either latched hard-sided containers or your car with the windows closed. Failure to properly store food and trash may result in a citation.
That exclamation point in there shows grudging respect for a worthy adversary.
The worthy adversary is a large black bird that is sometimes mistaken for a crow. Both ravens and crows are, in fact, members of the Corvidae family, which also includes jays and magpies.
Ravens are impressive. A fully grown one weighs in at about 2 1/2 pounds, measures 21-27 inches beak-to-tail, and sports a wingspan of about four feet. Dimensions like that make the raven the largest species of songbird (yes, that's how they're classified) and the world's largest all-black bird.
Common ravens are most emphatically black. Their long, thick, powerful beaks are black. The long, bristly feathers (filoplumes) covering their nostrils and the base of their bill are black. Their long, fluffy throat hackles are black. The feathers on their thick neck are glossy black, and so are the ones on their body, tail, and wings. Their short, sturdy legs are black. Heck, even their eyes are black. Ravens of both sexes look very much alike, though males tend to be larger.
Being so very black, and a carrion eater as well, the raven has been cast as a symbol of evil in many cultures. This meaning was conveyed with crystal clarity in Edgar Allen Poe's epic poem The Raven, which ends:
And the raven, never flitting, still is sitting, still is sitting
On the pallid bust of Pallas just above my chamber door;
And his eyes have all the seeming of a demon's that is dreaming,
And the lamp-light o'er him streaming throws his shadow on the floor;
And my soul from out that shadow that lies floating on the floor
Shall be lifted - nevermore!
People who see ravens for the first time might initially mistake them for crows, but not for long. Nearly everyone who gets a good look at a raven and hears it vocalize realizes that it cannot be a crow.
A raven often soars on thermals like a hawk, with decidedly less crow-like wing flapping, and may habitually fly down the centerline of a road (something crows seldom do) while searching for roadkill. The raven's tail when extended in flight is distinctively wedge-shaped, whereas a crow's is squared-off and shorter. The raven's neck is stretched longer in flight, and its wings are narrower and more pointy than a crow's too. If you look closely at the raven's wingtips, you can see longer, thinner feathers that are suggestive of fingers.
Up close, you can see that a raven is more massively built than a crow. Even its bill is larger and heavier than a crow's. If you see a raven sitting, and especially if it is calling, you'll notice that it sports a shaggy-looking set of throat hackles like no crow ever wore. It's likely you'll see that raven alone or paired-up with its lifelong mate. Chihuahuan ravens (C.cryptoleucus) excepted, the ravens you find here in North America seldom flock up like crows except for special occasions, such as picking over and defending a good garbage dump or roadkill. Ravens don't flock up and migrate long distances like crows do, either.
Nor does a raven sound like a crow. Both ravens and crows can produce an amazing assortment of sounds, but instead of the urgent high-pitched "caw" that is the crow's trademark, the raven's very distinctive common call is a low, drawn-out, croak-like, gurgling "kraaaah" or a deep, nasal/hollow "brooonk."
This site is a good place to compare raven and crow vocalizations [under Songs and Calls].
All of this said, it remains that knowing which bird you are looking at is largely a matter of knowing where you are. For various and sundry reasons, you will generally not find ravens inhabiting the same areas that crows do.
Where you do find ravens is in a range extending from the Aleutian Islands through Alaska and Canada and south throughout the mountain and desert West, parts of the Great Plains, and into northern New England, the upper Great Lakes, and the Appalachians as far south as northwestern Georgia. The margins of the range are malleable, of course, allowing for small seasonal adjustments and some anomalies such as the nesting pair recently reported in the New York City borough of Queens.
Ravens are highly adaptable birds that can successfully occupy a diverse assortment of both open and forested habitats. Thus, they inhabit not only the coniferous forests, rocky coasts, and mountainous or hilly land they prefer, but also deserts, prairies, tundra, Arctic ice flows, tidal flats, and agricultural fields. Ravens do OK around people, so they're commonly seen in rural settlements and on city margins.
Although ravens can live 30 years or more in captivity, the birds in the wild that survive to adulthood (first year mortality is 50%) probably live no longer than 6 to 13 years. That's plenty enough time to engage in a good deal of mischief and even create some genuine trouble.
Ravens are too bright, curious, and playful to confine their irksome behavior to pilfering food in ingenious ways. They'll make off with shiny things that people leave lying around. They'll steal golf balls right off the green. They'll peck holes in aircraft wings. They'll peel various materials off of buildings (including the radar absorbent material on structures at the China Lake Naval Weapons Center).
Some of the annoying things they do have nothing to do with intellect, as when they foul satellite dishes and power line insulators with their crap, sometimes even causing power outages.
Unfortunately, the big black birds make life difficult for some threatened or endangered species. Ravens are opportunistic omnivores whose diet is heavy on the meat side and includes carrion or garbage, small rodents, lizards, frogs, mollusks, insects, seeds, cultivated grains, wild fruits, and the nestlings and eggs of various birds and animals.
Their fondness for eggs and nestlings extends to those of rare or troubled species like the desert tortoise, California condor, least tern, snowy plover, sage grouse, and marbled murrelet. In some cases these depredations contribute significantly to a species' decline.
As you can easily imagine, it's tough to protect the nests and young of threatened and endangered species when their habitat is patrolled by clever, sharp-eyed ravens with appetites that are....well, ravenous. You can't easily shoo the problem birds away, and you can't just shoot them, trap them, poison them, or destroy their stick-built nests (usually in high trees or on cliffs, sometimes on cell phone towers, billboards, or what have you). Such drastic measures have been illegal, even on private land, ever since a 1972 amendment to the Migratory Bird Treaty between the United States, Canada and Mexico extended federal protection to all of the Corvidae, ravens included.
That means, for example, that National Park Service officials trying to keep ravens from excessively plundering the nests of endangered marbled murrelets in the old growth timber of Redwood National and State Parks are pretty much limited to warning visitors not to leave food or scraps where ravens can get at them. The logic behind this is that fewer murrelet nests will get spotted and robbed if you reduce the number of raven flights over trees containing murrelet nests.
Ending this discourse on a negative note would signal not just unfairness to ravens, but also disrespect for the intricate workings of natural systems. Like plants we call weeds only because they grow where we don't want them to, ravens get bum-rapped for nothing worse than behaving as evolution disposed them to. Corvus corax couldn't possibly have persisted as long as it has if its particular niche weren't supportive of other life on this planet. If you are looking for a bottom line, here it is: Love 'em or hate 'em, you need to learn to live with ravens.
Postscript: I live in South Carolina, where there are no wild ravens that I know of. When I have the good fortune to visit raven territory, which is never frequently enough, I invariably pause to admire them. The big black birds continue to amaze and delight me. Just last month, going along on a Kurt Repanshek-led death march in Arches National Park afforded me the opportunity to stand gape-mouthed as I watched a raven gracefully glide in one side of Delicate Arch and out the other. I am absolutely convinced that the damn bird flew through the arch to show off for us bystanders, and if I had the brains that God gave a turnip I wouldn't have neglected to record the event with the camera I was holding at the time.