In the Company of Crows and Ravens by John Marzluff, Mr. Tony Angell and Professor Paul R. Ehrlich
-001- The ancient Romans selected the raven as the head of all birds of omen,
-002- The larger corvids walk rather than hop on strong, black legs and toes. This walk is often interpreted as a strut, with “a lordly and somewhat military air.”
-003- Mentally, crows and ravens are more like flying monkeys than they are like other birds. This means that they are able to learn, remember, and use insight to solve natural and human challenges.
-004- Bird brains are not entirely like our brains. In all animals the forebrain is responsible for learning and memory. But in mammals like us, the enlarged parts of the forebrain are the hemispheres with the distinct convoluted surfaces known as the cerebrum. The frontal and temporal lobes of our cerebrum are most important to memory, planning, problem solving, attention, and imitation. In smart birds like corvids and parrots, the inner portion of the forebrain, especially the nidopallium, is pronounced. The nidopallium is densely packed with nerve cells, making it an efficient storage, processing, and coordinating center. We know that the forebrain is important to learning and memory because it is largest in birds that excel in learning tests. Damage to it reduces a bird’s learning ability. Another portion of the forebrain, known as the hippocampus, may be most important in spatial memory. In many corvids, chickadees, and tits (European chickadees) that cache seeds for future use, the hippocampus is huge. It may even expand during the autumn when caching is common and shrink during the spring when stored foods are used less. Large forebrains do more than aid with spatial memory. They also allow corvids to discriminate finely among similar objects,
-005- Black feathers are stronger than less pigmented ones,
-006- Black birds absorb more solar radiation on sunny days than do light-colored birds, which allows them to conserve precious body heat in cold environments.
-007- Mates groom each other by probing and combing their feathers to remove mites, flies, and other irritants, a practice known as allopreening. This social activity is reminiscent more of apes than of birds. Pairs function as highly synchronized teams, building large, stick-based nests, carefully lining them with fine rootlets or hair, and filling them on average with four bluish green, brown-flecked eggs.
-008- Incubation varies little among the many species and usually lasts three to four weeks. Occasionally up to ten eggs are incubated, but most pairs go for quality rather than quantity.
-009- Parents forage incessantly to feed their growing nestlings, which greet the world naked and helpless, a condition called altricial. Newborns weigh less than an ounce but quickly grow to nearly adult size before fledging from the nest at three to four weeks of age. Fledging refers to the act of leaving the nest and is generally the time when nestling crows become independent fliers. We call young crows fledglings after they can fly but before they are independent of parental care, a period that lasts several weeks to months in most crow species. The fact that newly fledged crows resemble adults in size and color often causes people to remark that they have never seen a baby crow. Certainly they have; they just haven’t noticed it. Closer inspection reveals that young crows and ravens are less glossy than adults and have a pale blue iris that turns dark brown only after several months of life. Detailed morphological studies reveal that throughout their first year of life crows have shorter tails and wings than older birds, browner and more worn plumage, and distinctly rounded rather than squared tail feather tips.
-010- Our early ornithologist friend Major Bendire, for example, noted in 1895 that crows walk “more jerky” and not nearly “as dignified as the raven.” Crows and ravens differ in many other respects. Ravens are large, often weighing more than 2.5 pounds (just over a kilogram) with prominent beaks, diamond- or wedge-shaped tails, and broad wings spanning more than 4.5 feet (1.4 meters). Crows typically weigh less than a pound (500 grams), with shorter and narrower beaks, fan-shaped tails, and wings spanning less than a yard (about a meter). Ravens often soar in flight, but crows usually flap, and their rate of wing beats is more rapid than the larger raven.
-011- The basso profundo krawk of the raven is easily distinguished from the comparatively anemic caw of the crow.”
-012- Ravens have perhaps the most complex vocabulary of any bird. They scream, trill, knock, croak, cackle, warble, yell, kaw, and make sounds like wood blocks, bells, and dripping water. Their calls are hoarse and resonant.
-013- Both species are capable mimics. Variety and unpredictability define crow, raven, and other corvid calls, so whenever you hear something inexplicable in the forest or field, odds are that a corvid is the source.
-014- the history of ecological interactions between crows and people. It is a history that reaches back far before the days of humans, to a time nearly one hundred million years ago, when Earth’s original two large continents, Gondwana and Laurasia, were drifting apart.’
-015- Kevin Omland, a former ski racer turned geneticist at the University of Maryland, ground up hundreds of raven feathers, extracted their DNA, and made a startling discovery. Not all “Common Ravens” are the same. The most common form, known as the Holarctic Clade, is found throughout the northern hemisphere in Europe, Greenland, Asia, and North America. But the less common California Clade is found only in North America, primarily along the southern Pacific Coast. Common Ravens must have been in southern North America two million years ago to participate in this divergence.
-016- Later, Holarctic birds once again crossed into North America, perhaps flanking wolves and people.
-017- the beneficial aspects of crows, Rooks, and Western jackdaws were appreciated through the late 1400s and early 1500s in England. There, corvids were legally protected from destruction because of the janitorial services they performed on city streets. A special decree in 1534 issued by King Henry VIII also protected corvids hunted for sport by falconers. English ravens were protected in the 150os because of their valuable service as scavengers of putrid meat. Crows and ravens signaled longevity from atop sheaves of grain in family crests of this period.
-018- Corvids in general were viewed as “vermin” in Europe throughout the 1700s, 18oos, and early igoos. In western Europe, ravens were driven from cities and hunted with such passion in the countryside that a “cultural gap” in their geographic distribution developed. Though they survived in Scandinavia, northern England, Spain, and southern and eastern Europe, ravens were extirpated from most of Germany, Poland, the Netherlands, Czech Republic, Hungary, Slovakia, Austria, and southeastern England. Some persecution was reduced in England and Scotland in 1981, when ravens received protection under the Wildlife and Countryside Act. Common Ravens remain protected today.
-019- In scientific language we call them human commensals or synanthropic birds. Crow fanatics refer to them as lofty messengers or incredible problem solvers.
-020- for every one hundred crows born in your neighborhood, at least five should live longer than forty years.’
-021- The Inuit, for example, tell how Crow tricked a great chief out of a daylight ball and flew high into the sky with it to illuminate and warm the far north for his people. The Tlingits tell of Raven achieving similar deeds.
-022- avens figure prominently in the folklore and religion of northern peoples around the world. The Norse God Odin was accompanied by two ravens, Hugin (thought) and Munin (memory), who surveyed the world during the day and reported back to Odin each
-023- Ravens were important inspirational and navigational tools to early Europeans. Warriors used the birds’ association with death to intimidate their enemies. Topping a Celtic battle helmet from Romania is an iron raven whose wings flapped as the warrior entered battle. Warriors also used ravens to practical ends. Much as Noah supposedly released a raven to find land, the Vikings located Iceland with the aid of ravens.
-024- One of the best known legends about ravens comes from seventeenth-century England. Despite building hatred of scavengers following the London fire of 1666, legend has it that six ravens were spared from persecution and allowed to live in the Tower of London. King Charles II had the birds brought to the tower after the royal astronomer, Sir John Flamstead, told him that if the ravens were killed, his kingdom would fall. A corps of raven masters was established to care for the birds. Not wishing to tempt fate, British rulers have kept ravens in the Tower of London ever since. When only one raven survived the assault of World War II, Sir Winston Churchill is reported to have ordered that more be brought in. Today’s Tower ravens have clipped feathers on one wing to keep them from flying off
-025- Boria Sax has researched the history of ravens at the Tower of London and made a startling discovery. There is no evidence that ravens were ever kept in the Tower before the late i8oos. The legend of Charles II and the ravens appears to be a myth, and a recent one at that. Sax argues that the legend of ravens protecting the kingdom was developed at the end of World War II, perhaps to buoy the spirits of shell-shocked Londoners, provide a living connection to ancient times, boost tourism, or to simply increase job security and esteem of the raven masters.
-026- It was believed that Raven’s greatest trick of all was to give each male animal testicles, so that he might be entertained by the silly games and preoccupations they then constantly engaged in.
-027- Ravens can also be called on to grant small wishes.
-028- Pueblo Indians made connections between crows, death, and bad luck. Their witches could transform into either crows or owls.
-029- when the Marzluff family traveled to Crow Agency, Montana, to learn more about the Crow people. Crow Agency is the geopolitical heart of the Crow Nation. The Crows are a rugged Native American people that once thrived on the cold, windswept plains of present-day eastern Montana, Wyoming, and southern Canada.
-030- In a moment that taught us more about Euro-Americans’ domination of the continent than hundreds of books and films ever could, a Crow woman said simply that her people’s English name was a mistake. Her ancestors, she explained, told early explorers that they were known as the “people of the large-beaked bird.” In error they interpreted the description to mean “crow,” and with such arrogance a people were named. The woman we spoke with said that “eagle” was the correct bird.
-031- Charles Dickens, himself a proud owner of a pet raven, incorporated the trials of Grip, the devil raven, in his novel Barnaby Rudge. Lewis Carroll put crows on the other side of the Looking-glass. To Alice’s delight, “a monstrous crow, as black as a tar-barrel,” broke up a fight between Tweedledum and Tweedledee so that Alice could get directions out of a forest in Wonderland.
-032- Crows provide many important lessons for life in the ancient Greek tales known as Aesop’s fables. Crow and Raven teach us that fair-weather friends are not worth much, that it is better to be quietly content than loudly defensive, and that we should be content with our appearance.
-033- Crows were commonly depicted on lacquered boxes, fans, and hanging scrolls in Edo Japan.
-034- The Screen of Crows
-035- The soul of King Arthur of the Round Table is supposed to survive today as a crow or a raven.
-036- Traveling the British countryside simply overwhelms you with the influence of corvids on language. Place-names echo a corvid past. Great Rave-ley, Raven Beck, Ravencroft Belt, Raven Scar, Ravenscleugh, Ravenscliffe, Ravens Close, Ravensheugh Crags, Ravensnest Wood, and Ravenglass are just a few. Ravenstone was a European execution site. In Scotland, ravens are known as “corbies,” and the Highlands resound with places like Corb Glen, Corbie Head, Corbie Nest, and Corby’s Crags.
-037- 181 names for crows and ravens from 136 human languages on five continents and many islands. Most names are similar and distinctly onomatopoetic. Most include a “k” consonant sound and an “a” vowel. Well over half of the words for crow worldwide include “ka” or “ak.” Finns, for example, call ravens “korpi” and Poles call them “krucks.” Batanes Island Itbayats call crows “quwaks,” Pawnees call them “kaaka,” and Thai call them “kaa.” Certainly these reflect the cawing, clucking, and croaking calls typical of crows and ravens.
-038- Crows and ravens care for each other, spend years living at home, engage in foreplay, and mate for life but now and then mate with others. They sunbathe, smear natural oils on their skin, and play.
-039- Mated pairs cooperate in nearly every nuance of life, but compete with other pairs for territories. Unmated crows variously compete and cooperate with their parents, siblings, neighbors, and members of large migrating or roosting groups. In crow society, large numbers of individuals interact rarely, but are familiar with each other. Throughout their lives, most individuals have sustained relationships with a few other individuals. Central among these stable relationships is the lifelong, monogamous mated pair. This fundamental unit of crow society defends a territory, ranging from the immediate nest area in Northwestern Crows to hundreds of acres (hectares) in Common Ravens, for their exclusive use throughout their lives.’
-040- All crows have some exposure to family life, living with their parents and siblings for at least the first few months after fledging. Some young crows remain with their parents and perhaps up to six siblings and half-siblings for a year or more. However, all crows do not experience long-term family life. Instead, some leave their parents after a few months to disperse widely, wander locally as unmated “floaters,” or even form a pair-bond to breed in their second year. Female crows usually disperse and occasionally breed in their second year. Males may wander locally and rarely breed before their third year of life. Whether crows wander or remain in families, they all eventually participate in much larger social gatherings, most commonly during winter, as they forage in flocks or roost in impressive, nighttime aggregations.
-041- Although Common Ravens are among the least social, living as mated pairs during their adult lives, they do flock together at rich food resources during the winter and spend their early years in the company of tens to hundreds of other young, albeit nomadic, ravens.
-042- Seasonally, most crows go from living with their mate and/or family and interacting with a small number of neighbors in spring and summer to interacting with larger groups during fall and winter.
-043- In general, dispersers sought out breeding areas similar to the ones they were born in; rural crows dispersed to other rural areas and suburban crows dispersed to other suburbs.
-044- Common Ravens may rarely have helpers. Helpers do not necessarily increase the annual reproductive success of the pair they help.
-045- adult crows interact regularly throughout the year by calling softly to each other and giving each other a good deal of physical attention by gently grabbing bills and grooming each other’s feathers. Corvids groom each other to an unprecedented extent among birds. This “allopreening” is common in primates but not in birds. In allopreening, one partner edges up to the other, bows its head slightly, and raises its head feathers. Using a dexterous beak, the partner then grooms its mate by picking through the feathers just like a deftly fingered primate grooms its social companions. Allopreening is usually confined to the top of the head and facial area and serves the utilitarian function of removing parasites from hard-to-reach places. Allowing another bird so close when the recipient is vulnerable, however, suggests that this behavior may also provide an important social function related to maintaining the pair-bond.
-046- Gently grabbing beaks, known as “allobill- ing,” is less common in crows than it is in ravens. It involves mutual mouthing that often escalates into sharp jabs and brief fighting.”
-047- Even established pairs of crows court each spring. Males display their flying skills with acrobatic dives and rolls above observant females.
-048- Crows, especially female crows, “like” foreplay, but what sex they have is quick. Ritualized displays precede sex in most birds, including crows.
-049- He describes the basic display as “the male, the female, or both crouched with body horizontal, wings out and drooping, and tail vibrating up and down.” Females always performed the display, but males did not. Displaying crows also often vocalized, being especially prone to uttering soft cu-koo calls.
-050- On warm, sunny days crows will orient themselves perpendicular to the sun, spread their feathers, droop their wings, and lie prostrate on the ground in what looks like a semiconscious state. This odd behavior is common during the late summer molting period or after a prolonged cold, wet spell. Their partially closed eyes glaze over, and their mouths may open to help cool their sun-drenched bodies. Whole family groups may litter the ground seemingly dead, but if you try to approach they quickly come to life and move away.
-051- What are these sunbathing beauties doing? Apparently, the solar radiation turns the birds’ natural preen oil into a source of vitamin D. Ingesting it after sunning during normal preening activity could therefore provide an important dietary supplement. Sunning may also cause some skin and feather parasites to become more active and hence more accessible to preening birds.
Crows sometimes sprawl out around the mounds of acid-producing ants. This craziness, or “anting,” is a crow’s version of an insecticide application. Anting crows grab ants with their beak, crush them, and wipe the natural oils across the underside of their wing feathers. Formic acid and pungent anal fluids squeezed from ants have insecticidal properties that may drive unwanted parasites from the bearer’s body. During anting, live ants may also crawl on crows and actually eat some of the tiny troublesome creatures out of a beak’s reach. But could anting have an even more subtle function? Some speculate that the formic acid squeezed from ants is intoxicating to birds.
-052- Crows play. Once thought to be reserved for people, play has been increasingly found in animals, especially long-lived social ones like crows. Young American Crows have been seen grabbing paper in the bill, leaping into the air, dropping the paper, and pouncing on it again.
-053- On the snowy hills of Maine, Common Ravens play with sticks, bones, and other objects. But what really strikes you is their preoccupation with “body surfing” on snow. We have seen them slide down a slope on their bellies only to get up, hop back to the top, and do it again.
-054- He reports crows hanging upside down from moss and swinging back and forth, routinely engaging in tug-of-war contests over inanimate objects like sticks and plants, occasionally taking sticks into the air where they are dropped and recaught before hitting the ground, and repeatedly rolling a dried raccoon skull down a stump. Kilham also saw playlike behavior between crows and other animals. A consistent theme in these interactions was dancing: crows apparently imitating the mating dance of cranes or jumping high over animals like calves and vultures. McCaw, Tony Angell’s pet raven, routinely chased his husky dog.
-055- As crows increasingly interact with people, they begin to play with some of our own toys. Carrion Crows and Jungle Crows steal and roll baseballs, tennis balls, and golf balls. Mostly this play is rudimentary and done by single birds.
-056- But occasionally crows seem to just have it out for some people for no apparent reason. We often hear from red-haired women and balding men that they are swooped on by crows.
-057- Roosts have been christened “information centers” because they appear to serve as debriefing arenas for hunters each evening. Birds were thought to disperse in many directions from the roost each morning to hunt and forage rather independently. On arriving at the roost in the evening or as they left the next morning, successful hunters would divulge their secrets vocally or with a variety of postural displays and lead unsuccessful hunters to food. Common Ravens do exactly that. Young, vagrant, nonbreeding ravens that find large animal carcasses are rarely allowed to feed on them alone because of defensive resident territorial adults. So these vagrants return to communal roosts and inform others about newly found distant foods.
-058- Common Ravens in southwestern Idaho may have learned enough to evolve a new roosting culture. These ravens act like Staten Island crows, feeding on predictable agricultural products like corn, feedlot waste, small
rodents, and bugs. They roost in huge numbers and do not regularly recruit roost mates to new food bonanzas.
-059- The clucking of Common Ravens symbolically represents a dangerous invader near the nest. But their trilling indicates a trespassing challenger.
-060- the Common Raven utters nearly eighty distinct calls. An individual raven does not use all eighty. Individual birds utter about twenty basic calls, but each is variable in intensity, duration, pitch, and rate. Many vocalizations are individually distinct so that the caller’s aim and identity are stamped onto each utterance.
-061- Crows give at least three distinguishable assembly caws that are associated with mobbing, scolding, and diving at potential predators. These “two-syllable caws,” “long caws,” and “harsh caws” focus American Crows on the object of the caller’s scorn-usually a stationary cat or owl-in an attempt to drive the creature from the area, alert others to its presence, or perhaps teach family and flock members about dangerous situations. A variety of playback experiments confirmed what crow hunters have long known; if you broadcast these calls to crows, they will come flying toward you nine times out of ten. Even French corvids understand the American Crows’ message.
-062- If assembly caws are the “on” switch for American Crow attacks, then dispersal caws are the “off” switch. Harmonically complex, initially inflected, koaws are the most stereotypical dispersal call. These are given in response to immediate danger and cause birds to fly away from the scene, although they may initially attract crows to see the predator before they disperse.
-063- Koaws are often intermixed with or blended into harsher assembly caws. They are given during territorial defense in addition to mobbing. These facts led Cynthia Sims Parr to a striking conclusion: koaws may be given to intruding crows, not predators. American Crows leave at the utterance of a koaw not because of a dangerous predator but because of threat from a peeved territory owner.
-064- The ko, or warning caw, alerts crows to impending danger. It is a sharp, tonal caw given to predators heard or seen from a distance.
-065- Field researchers can often guess with good accuracy what crows are mobbing based on the intensity of their caws, suggesting that they may be identifying the intruder as well as scolding it.
-066- Caws of all durations are used to defend the territory, but their coupling with descending glides as the wings are held up in a U-shaped, or dihedral, position is typically used to announce one’s arrival at a gathering.
-067- Crows and ravens make a variety of soft squawks, coos, bill clicks or snaps, rattles, cackles, and growls as they sit alone or close to a mate or family member. The unstructured “gargling” or “rambling” soliloquies of young, unmated American Crows and Common Ravens involve combinations of these and mimicked noises from their locale.
-068- Crows and ravens enhance their natural repertoires by mimicking the sounds of other animals, including people, and inanimate objects. Don’t be surprised to discover that the dog you heard barking, the owl hooting, the child screaming, or the chicken clucking and crowing was actually a crow. Crows have been recorded mimicking all of the above. Crows can also speak fine English. Their complex throat muscles allow them to verbalize such phrases as “I’m Jim Crow” or “Oh my God, oh Lord.” This they do expertly without the need for their tongue to be split, a cruel and unfounded suggestion made two thousand years ago by Pliny the Elder. As Pete Byers writes in his book The Lost Folk Art of Crow Taming, all you need to get your crow to talk is “patience, perseverance, and repetition.” His Ohio-born crow, Edgar, imitated the cheering, hooting, and clapping that accompanied a television game show. Mickey, the crow at the National Aviary in Pittsburgh, greets visitors with “Hey bro, what’s happenin’?”
Mimicking need not be mindless copying. Konrad Lorenz’s pet raven Roah learned to mimic his name and then used it in new and appropriate contexts. When Roah perceived that Lorenz was heading toward a dangerous situation, lie would fly in another direction and repeatedly call “roah, roah” to lure Lorenz to safety.
-069- Crows do not sing to attract mates like other birds. Courtship is apparently done at close range using mixtures of soft sounds, bowing postures, and mutual caresses. Crow pair-bonds are likely formed over long periods in nonbreeding group settings without the vocal fanfare that accompanies pairing in most songbirds.
-070- Mates are more likely to increase their aggression and engage in “pincer tactics” after duetting than after solo cawing. Crows using pincer tactics surround an intruder, with the female on one side and her mate on the other.’
-071- The complexity of a communication system such as that of the American Crow and Common Raven is rarely matched in the animal kingdom.
-072- Crows also appropriately interpret our gazes, strides, and vocal signals. Stare at a crow, and it will become alert and likely move away. Walk quickly past, and it will ignore you. Develop a regular ritual of movements before you put food in your bird feeder and crows will anticipate and move toward the feeder when you begin your “feeding sequence.” Ravens are adept at following the gaze of people and probably many other animals they encounter.
-073- Common Ravens disappeared as nesting birds in southern Michigan after only a decade of land conversion (1860-1870), and the last raven in Nebraska was seen in 1936.
-074- Ravens are intolerant of close neighbors. Despite efficiently exploiting distant resources and reproducing at a high rate near people, ravens cannot attain densities anywhere near that achieved by crows because pairs aggressively defend most of their large home ranges from other neighboring pairs.
-075- The crow’s ability to learn exactly what to eat in a human-dominated environment can be impressive, even to a child. Eight-year-old Zoe Marzluff proved this by offering crows a choice of fried potatoes in two types of bags. One bag was from a McDonald’s restaurant, and the other was a plain brown bag. Crows consistently approached the McDonald’s bag before the plain bag, even though both were within a yard (meter) of each other, of the same size, and contained the same food. Crows had apparently learned to associate the restaurant’s logo with a tasty snack.
-076- spring away from some unseen danger. Tense and fearful ravens typically jump up as if their toes were pinched, performing what we call “jumping jacks” as they approach new foods.
-077- it seems that each neighborhood has at least one resident who makes a daily ritual of feeding crows specially delivered nuts, pet food, or table scraps. Crows solicit food from these people by congregating at their residence and calling. People respond by whistling or yelling encouragement to the crows to come ever closer. Often crow families will interact with such people for years or decades, eventually nesting nearby and even engaging pets and family members in games.
-078- as the dog or as cuddly as a cat. This is not to say that a crow raised singly from the time it is a young nestling does not make a good pet. It does. It follows its adopted human like a puppy, runs to it for protection, may sleep in the human’s or other pet’s bed, affectionately preens hair expecting reciprocity, and assumes that it should act as humanlike as possible.
-079- It seems that tame corvids cannot resist prying, probing, pulling, pushing, or penetrating anything that has the likelihood of opening up or having something beneath its surface.
-080- We know of many pet ravens that routinely strip the rubber from any available windshield wiper in the owner’s neighborhood. Those allowed free exit from the home are infamous for pounding on the neighbor’s house at the crack of dawn, stealing laundry, or tormenting the nearby dogs and cats. Bill Gilbert wrote about his pet crow, Hello, which stole cigarettes and spectacles, finished off fuzzy navels (orange juice and peach schnapps), and cached spoons, spark plugs, coins, pencils, eyeglasses, rings, and beads. Pete Byers’s crow, Edgar Allan Crow, showed an interest in ichthyology. Edgar “collected” the family angelfish and stored them by pressing them neatly between the pages of an old book for safekeeping, just as botanists do with plant specimens. It is our inability to take the mischief out of the trickster that we think
|by V. L. Craven|
In the Company of Crows and Ravens by John Marzluff, Mr. Tony Angell and Professor Paul R. Ehrlich