Post by Mysti on Aug 6, 2007 19:15:03 GMT -5
Raven
By Susa Morgan Black
PART ONE
CORVIDOLOGY
If men had wings and bore black feathers,
few of them would be clever enough to be crows.
- Rev. Henry Ward Beecher
If you are fascinated with ravens, read incessantly about them, observe them in nature, can recognize their unique voice, collect their feathers, collect raven art and artifacts, and know their literature and folklore from around the world, you are probably an amateur CORVIDOLOGIST, which is the branch of Ornithology specializing in RAVENS and their family. And magically speaking, Raven is your totem.
Genus
Raven (Corvus corax), also known as the Common Raven or the Northern Raven, is the largest bird in the family CORVIDAE or CORVINI. Raven's closest relatives in the subspecies CORVUS include the crows, jackdaws, and rooks. More distant Corvid cousins are Choughs, Treepies, Nutcrackers, Magpies and Jays.
There are many species of ravens around the world - Australian Raven (Corvus coronoides), Little Raven (Corvus mellori), Forest Raven (Corvus tasmanicus), New England Raven (Corvus (t). boreus), Chihuahuan Raven (Corvus cryptoleucus), Dwarf Raven (Corvus (r). edithae), Brown-necked Raven (Corvus ruficollis), White-necked Raven (Corvus albicollis), and Thick-billed Raven (Corvus crassirostris)
Habitat
Most of us are familiar with the Common, or Northern Raven. It is the most widespread of all corvids, ranging throughout Europe, North Africa, Western Siberia, North America and Greenland. The bird prefers wild upland and mountainous regions, but also inhabits forests, inshore islands, coastal areas, steppes, semi-deserts, and plains. I have observed these expert foragers in cities and suburban areas as well.
Appearance
Raven is a striking all black bird, 58 - 69 cm from beak to tail. Orthinologists believe that the all black plumage helps them absorb and retain heat in high altitudes and northern latitudes.
Distinctive features (to help you distinguish them from crows) are their large size, heavy bill, shaggy throat hackles, long fingered wing tips and long wedge shaped tail. In aerial silhouette their longer features (bill, tail and fingered wings) easily distinguish them from crows.
On closer observation (and they are often displayed in zoos) you will notice the strongly decurved distal part of the culmen, with prominent nasal bristles. The throat feathers are long and pointed, the tail is long and graduated. The entire body is glossy black, as are the bills, legs and feet. The black glossy feathers go slightly greenish on the head, under parts, tail and primaries, and bluish-purple on upper parts, secondaries and wing coverts. Their irides are dark brown.
Females measure smaller, but are not easily distinguishable from males. Juniors are a duller blackish brown until their second year.
The voice is normally a distinctive deep, harsh croak, or hollow croaking honk. Ravens have a large, complex vocabulary of sounds in their repertoire including a high knocking "toc toc toc", a dry, grating "Kraa", low guttural rattles, and some more musical calls. Captive birds have even been taught to speak.
Breeding
They are solitary nesters, creating bulky nests out of twigs and branches lined with roots, moss, wool, and rags daubed with mud and dung. They build frequently on cliff faces or high in large trees, but have been known to nest in old buildings, or even in low bushes or on the ground in undisturbed open country.
Their clutch consists of three to seven (averaging five) eggs in various shades from light blue to greenish blue or blotched olive, gray and brown. Ravens usually lay in February, but it varies depending on the climate (as late as April in Greenland, or as early as December in Pakistan). Incubation is 18 - 21 days, with a sitting female, and the male will bring food to the nest. The young ravens fledge at 35 - 42 days, are fed by both parents, and stay with the pair for six months afterwards.
Habits
<o:p>
We usually observe ravens in pairs or family parties, but non-breeders gather in large groups at feeding sites or communal roosting. Their territories are large (between 17 and 44 sq. km), but with few disputes as they are tolerant of other birds. Flocks usually number in the tens, but flocks of more than 100 have been seen at feeding sites in harsher environments such as Iran or the Shetlands, or in winter.
Ravens enjoy playful flight patterns, such as soaring, tumbling and rolling. Their longer wings make them quite agile aerial acrobats.
Lifespan
A wild raven can live more than thirty years.
Diet
They are omnivorous eaters, preferring to scavenge, but able to kill when necessary. They prefer carrion - dead sheep, cattle, rabbits and fish, but will also eat nestling birds and eggs, rodents, shellfish, insects, seeds, berries and grain. They have been known, in Greenland, to hunt and kill ptarmigan in flight, and to kill puffins emerging from their burrows. Ravens will also hide and store food for later use. Near human habitations, they boldly scavenge in garbage dumps and for slaughter house scraps.
In northern regions they have been observed to hunt cooperatively with wolves. Ravens will alert wolves to prey, wait for the kill, then feed. Wolves and ravens have also been seen to engage in playful behavior with each other, ravens swooping down at the wolves, who will chase them playfully.
Enemies
Ravens have been heavily persecuted by man, especially in farmlands where they will eat the seed and grain. In some regions the species have disappeared completely.
Corvophobia is the unnatural fear of corvids, especially ravens and crows. This fear has been promulgated throughout literature, such as the words of Edgar Alan Poe, who described them as ". . . grim, ungainly, ghastly, gaunt and ominous creatures." This is unfortunate, because they, in fact, are more helpful than harmful. Only one percent of their omnivorous diet consists of corn, while actually they prefer to devour agricultural pests such as grubs, caterpillars and worms. A study in New York found a single family of crows to devour about forty thousand pests in one nesting season.
In the animal world, ravens natural enemies are the great horned owl and red tail hawk. Ravens will cooperate together and mob these bigger birds to drive them off.
Intelligence
In spite of these obstacles, ravens (as well as the other corvids) are a highly successful species due to their high level of intelligence, flexibility, and adaptability.
In The Audobon Society Encyclopedia of North American Birds, ornithologist John Terres writes, "Corvids have probably achieved the highest degree of intelligence to be found in any birds." Animal behaviorist Konrad Lorenz agrees, writing that raven has the "highest mental development" among the avian species. Naturalist Tony Angell has proven in controlled laboratory experiments that ravens are "superior in intelligence to all other avian species tested." Irene Pepperberg, of the University of Arizona, has gone even further, stating that corvids share "the cognitive capacities of many primates."
A tale told by Aesop informs us that the intelligence of corvids has long been known. A thirsty crow found a pitcher of water, but the water was too far below the rim for his beak to reach. The clever crow began dropping pebbles into the pitcher, raising the water level until it reached the brim, where she could quench her thirst.
At Oxford University in England, ornithologists conducted an unusual experiment with two New Caledonian Crows named Betty and Abel, reported in the August 9, 2002 issue of the journal Science. They placed a tiny bucket of meat inside a pipe, and left two pieces of wire in their cage, one hooked and one straight, to see if the birds would choose the hooked wire to retrieve the bucket of meat, proving that birds were "tool users" on a par with higher levels of animal intelligence.
"We were delighted and extremely surprised" reported Alex Kacelnik, one of the bird experts studying the crows, when Abel stole the hooked wire from Betty, and rather than giving up, Betty "modified" the straight wire into a hooked wire, and was thus able to hook the bucket, pull it up, and retrieve her snack. This elevates ravens from "tool users" to "tool makers", which places them on a par with primates.
According to neurologist Stanley Cobb, birds do not have a complex cerebral cortex, such as mammals do, but rather, they have developed their hyperstraiatum, a part of their forebrain, that can carry out complex functions. Corvids, especially Ravens, Crows, and Magpies, have the largest brain size (i.e. the largest number of brain cells) among birds, including the largest hyperstriatum.
(Sources - Crows and Jays, A Guide to the Crows, Jays and Magpies of the World, by Steve Madge and Hilary Burn, Houghton Mifflin Company, Boston, New York, 1994; Bird Brains by Candace Savage, Sierra Club Books, San Francisco, 1995)
By Susa Morgan Black
PART ONE
CORVIDOLOGY
If men had wings and bore black feathers,
few of them would be clever enough to be crows.
- Rev. Henry Ward Beecher
If you are fascinated with ravens, read incessantly about them, observe them in nature, can recognize their unique voice, collect their feathers, collect raven art and artifacts, and know their literature and folklore from around the world, you are probably an amateur CORVIDOLOGIST, which is the branch of Ornithology specializing in RAVENS and their family. And magically speaking, Raven is your totem.
Genus
Raven (Corvus corax), also known as the Common Raven or the Northern Raven, is the largest bird in the family CORVIDAE or CORVINI. Raven's closest relatives in the subspecies CORVUS include the crows, jackdaws, and rooks. More distant Corvid cousins are Choughs, Treepies, Nutcrackers, Magpies and Jays.
There are many species of ravens around the world - Australian Raven (Corvus coronoides), Little Raven (Corvus mellori), Forest Raven (Corvus tasmanicus), New England Raven (Corvus (t). boreus), Chihuahuan Raven (Corvus cryptoleucus), Dwarf Raven (Corvus (r). edithae), Brown-necked Raven (Corvus ruficollis), White-necked Raven (Corvus albicollis), and Thick-billed Raven (Corvus crassirostris)
Habitat
Most of us are familiar with the Common, or Northern Raven. It is the most widespread of all corvids, ranging throughout Europe, North Africa, Western Siberia, North America and Greenland. The bird prefers wild upland and mountainous regions, but also inhabits forests, inshore islands, coastal areas, steppes, semi-deserts, and plains. I have observed these expert foragers in cities and suburban areas as well.
Appearance
Raven is a striking all black bird, 58 - 69 cm from beak to tail. Orthinologists believe that the all black plumage helps them absorb and retain heat in high altitudes and northern latitudes.
Distinctive features (to help you distinguish them from crows) are their large size, heavy bill, shaggy throat hackles, long fingered wing tips and long wedge shaped tail. In aerial silhouette their longer features (bill, tail and fingered wings) easily distinguish them from crows.
On closer observation (and they are often displayed in zoos) you will notice the strongly decurved distal part of the culmen, with prominent nasal bristles. The throat feathers are long and pointed, the tail is long and graduated. The entire body is glossy black, as are the bills, legs and feet. The black glossy feathers go slightly greenish on the head, under parts, tail and primaries, and bluish-purple on upper parts, secondaries and wing coverts. Their irides are dark brown.
Females measure smaller, but are not easily distinguishable from males. Juniors are a duller blackish brown until their second year.
The voice is normally a distinctive deep, harsh croak, or hollow croaking honk. Ravens have a large, complex vocabulary of sounds in their repertoire including a high knocking "toc toc toc", a dry, grating "Kraa", low guttural rattles, and some more musical calls. Captive birds have even been taught to speak.
Breeding
They are solitary nesters, creating bulky nests out of twigs and branches lined with roots, moss, wool, and rags daubed with mud and dung. They build frequently on cliff faces or high in large trees, but have been known to nest in old buildings, or even in low bushes or on the ground in undisturbed open country.
Their clutch consists of three to seven (averaging five) eggs in various shades from light blue to greenish blue or blotched olive, gray and brown. Ravens usually lay in February, but it varies depending on the climate (as late as April in Greenland, or as early as December in Pakistan). Incubation is 18 - 21 days, with a sitting female, and the male will bring food to the nest. The young ravens fledge at 35 - 42 days, are fed by both parents, and stay with the pair for six months afterwards.
Habits
<o:p>
We usually observe ravens in pairs or family parties, but non-breeders gather in large groups at feeding sites or communal roosting. Their territories are large (between 17 and 44 sq. km), but with few disputes as they are tolerant of other birds. Flocks usually number in the tens, but flocks of more than 100 have been seen at feeding sites in harsher environments such as Iran or the Shetlands, or in winter.
Ravens enjoy playful flight patterns, such as soaring, tumbling and rolling. Their longer wings make them quite agile aerial acrobats.
Lifespan
A wild raven can live more than thirty years.
Diet
They are omnivorous eaters, preferring to scavenge, but able to kill when necessary. They prefer carrion - dead sheep, cattle, rabbits and fish, but will also eat nestling birds and eggs, rodents, shellfish, insects, seeds, berries and grain. They have been known, in Greenland, to hunt and kill ptarmigan in flight, and to kill puffins emerging from their burrows. Ravens will also hide and store food for later use. Near human habitations, they boldly scavenge in garbage dumps and for slaughter house scraps.
In northern regions they have been observed to hunt cooperatively with wolves. Ravens will alert wolves to prey, wait for the kill, then feed. Wolves and ravens have also been seen to engage in playful behavior with each other, ravens swooping down at the wolves, who will chase them playfully.
Enemies
Ravens have been heavily persecuted by man, especially in farmlands where they will eat the seed and grain. In some regions the species have disappeared completely.
Corvophobia is the unnatural fear of corvids, especially ravens and crows. This fear has been promulgated throughout literature, such as the words of Edgar Alan Poe, who described them as ". . . grim, ungainly, ghastly, gaunt and ominous creatures." This is unfortunate, because they, in fact, are more helpful than harmful. Only one percent of their omnivorous diet consists of corn, while actually they prefer to devour agricultural pests such as grubs, caterpillars and worms. A study in New York found a single family of crows to devour about forty thousand pests in one nesting season.
In the animal world, ravens natural enemies are the great horned owl and red tail hawk. Ravens will cooperate together and mob these bigger birds to drive them off.
Intelligence
In spite of these obstacles, ravens (as well as the other corvids) are a highly successful species due to their high level of intelligence, flexibility, and adaptability.
In The Audobon Society Encyclopedia of North American Birds, ornithologist John Terres writes, "Corvids have probably achieved the highest degree of intelligence to be found in any birds." Animal behaviorist Konrad Lorenz agrees, writing that raven has the "highest mental development" among the avian species. Naturalist Tony Angell has proven in controlled laboratory experiments that ravens are "superior in intelligence to all other avian species tested." Irene Pepperberg, of the University of Arizona, has gone even further, stating that corvids share "the cognitive capacities of many primates."
A tale told by Aesop informs us that the intelligence of corvids has long been known. A thirsty crow found a pitcher of water, but the water was too far below the rim for his beak to reach. The clever crow began dropping pebbles into the pitcher, raising the water level until it reached the brim, where she could quench her thirst.
At Oxford University in England, ornithologists conducted an unusual experiment with two New Caledonian Crows named Betty and Abel, reported in the August 9, 2002 issue of the journal Science. They placed a tiny bucket of meat inside a pipe, and left two pieces of wire in their cage, one hooked and one straight, to see if the birds would choose the hooked wire to retrieve the bucket of meat, proving that birds were "tool users" on a par with higher levels of animal intelligence.
"We were delighted and extremely surprised" reported Alex Kacelnik, one of the bird experts studying the crows, when Abel stole the hooked wire from Betty, and rather than giving up, Betty "modified" the straight wire into a hooked wire, and was thus able to hook the bucket, pull it up, and retrieve her snack. This elevates ravens from "tool users" to "tool makers", which places them on a par with primates.
According to neurologist Stanley Cobb, birds do not have a complex cerebral cortex, such as mammals do, but rather, they have developed their hyperstraiatum, a part of their forebrain, that can carry out complex functions. Corvids, especially Ravens, Crows, and Magpies, have the largest brain size (i.e. the largest number of brain cells) among birds, including the largest hyperstriatum.
(Sources - Crows and Jays, A Guide to the Crows, Jays and Magpies of the World, by Steve Madge and Hilary Burn, Houghton Mifflin Company, Boston, New York, 1994; Bird Brains by Candace Savage, Sierra Club Books, San Francisco, 1995)