Ravens versus crows - help needed
I am trying to tell whether the big black bird on the roof across the backyards is an American Crow or a Common Raven. Can anyone give me advice on how to tell them apart? The bird books mostly mention size - is there anything else? I'm in Arlington, Virginia in a neighborhood with small, suburban backyards. I'm trying to identify them for the Great Backyard Bird Count. Thanks!
Views: 201
Replies to This Discussion
-
Permalink Reply by Laura Erickson on -
It would be shocking in Arlington to have ravens hanging around in town. But when crows and ravens are perched, the ways to tell them apart are 1) crows have a sleek bill while ravens have more a Jimmy Durante one--it's much thicker. 2) ravens have shaggier throat feathers.
If they fly, you'll notice that crow tail feathers are about the same lengths, so the tail makes a fairly even fan. The central tail feathers of ravens are significantly longer than the outer ones, and the tail tapers to make a pointed keel.
If they call, you can hear a definite "caw caw" from crows--ravens croak.
Because the two species' bodies are proportioned so identically, size doesn't help unless they're sitting side by side.
-
Permalink Reply by Susan Casey-Lefkowitz on -
Thanks - very helpful. I'll put crow for my GBBC list and know what to look for next time.
-
Permalink Reply by Charlotte Stahl on -
Susan,
I found this info on a quick web search and thought you might be interested. Isn't the internet great? You can usually find anything you want with just few words and/or clicks. I hope this helps you out.
Charlotte : }
Physical Differences: Crows average around 17 inches long, and ravens about 24-27.
* A raven weighs about four times that of a crow.
* Crows have a wing span around 2.5 ft., and ravens about 3.5-4 ft.
* A raven's wing sometimes makes a prominent "swish, swish" sound, while a crow's wing beat is usually silent.
* Ravens have pointed wings, while crows have a more blunt and splayed wing tip.
* Crows have a fan-shaped tail (squared-off), while raven tails are long and wedge-shaped.
* Besides having a bigger, more powerful bill, a raven's bill is curved, while a crow has a more-or-less flat bill. Additionally, atop a raven's bill is a tuft of hairs absent on crows.
* As a result of being larger and more powerful, ravens are the more efficient predator. (Predation is a very small percentage of crow and raven diets.)
Range/adaptive skills: While both crows and ravens have experienced persecution in the eastern United States, the crow managed to adapt and increase in numbers, while the ravens greatly declined (although recently the raven is making a comeback in places like Maryland). B.Heinriech says this may be due, in part, to the raven's propensity to reuse nest sites, which are easy to find and destroy. Additionally, ravens, utilizing carrion more than crows, probably disappeared along with the wolves and buffalo. Poisons to rid wolves from the landscape also contributed. Agriculture, however, increased in the east, increasing the crow's food base and ability to increase in numbers.
* Crows are more at home in the urban landscape, given their ability to be more socially inclined than ravens.
Diet: While both are commited to being vociferous omnivores, ravens are drawn to carrion (especially sheep), while crows may be less picky.
* Ravens probably find food faster in the wild, considering anecdotes from tappers about how fast ravens could find the carrion in their traps.
Vocalizations: For the sake of basic reference, a crow's call is a "caw" and a raven's is a low and slow croak.
* Crows exhibit at least two dozen different calls, while ravens can express themselves with 20-100's of different vocalizations, depending on the expert cited.
Inter species relations/behavior: L. Kilham, from The American Crow and the Common Raven (1989) wrote that he observed ravens repeatedly chasing crows from a feeding station, always resulting in the crow dropping the cache. This would unnerve the crows to no-end; causing them to gather at a roost and caw vehemently, yet they still repeated the cycle.
* Jollie (1976) stated that ravens seldomly attack crows because crows can outmaneuver and outclimb them. However, Kilham observed the opposite to be true at the New Hampshire farm study site, where the ravens outmaneuvered the crows in the forest and well as in the open.
* Kilham observed crows doing fewer jump-backs when approaching food. Ravens are more cautious or less audacious. (Jump-backs are reactions that crows and ravens do in times of caution, possibly testing for a reaction from the possible food source.) Furthermore, Conner (1975) noted that ravens would not approach a landfill until there were at least four crows present. After awhile if no crows were present, they would use their own lookouts. Several accounts exist of ravens using crows as their sentinels.
* While subjective, limited, and hard to extrapolate from, Kilham's hand-raised raven liked being indoors much more than the hand-raised crow. Additionally, he noted that the raven liked low place (chairs, counters) while the crow liked higher spots such such as atop a door.
* Ravens at times will fly wing-to-wing with their mate, with the females just below the males.
* Science: Bernd Heinrich, an academic field biologist, spent four consecutive winters at a cabin in Maine watching ravens at feed stations, attempting to fill-in a piece of the puzzle to a question concerning an obvious paradox he witnessed with the ravens. The question that pervaded his mind occurred while he was doing some work on bees: He had observed ravens at a carcass "sharing" the prized meat and wondered why a pair of ravens would not defend such a prize at a time when meat supply was scarce. The logical, and proper evolutionary response would seem contrary, with the discovers indignantly fending-off other prospective takers.
After his four winters of observation and experimentation, he learned that the raven's (unmated juveniles) possibly "recruit" others to a food source because, by sharing with others it gains "friends," from which it may gain a mate from in the future due to its foraging abilities. While mated pairs are more-or-less anchored to their localized nesting area; low status juveniles are left to form wandering unmated "gangs." Thus, mated pairs would not benefit from "recruiting" others to a food source, and likewise, juveniles are careful not to tip-off dominant mated adults.
More information can be obtained from Ravens in Winter, by Bernd Heinrich (1989).
-
Permalink Reply by Susan Casey-Lefkowitz on
-
Charlotte - thanks so much for looking all that up. It is so interesting and now I need to travel somewhere to see ravens! Susan
-
Permalink Reply by Charlotte Stahl on
-
You're very welcome. One thing not mentioned was how very intelligent both Crows and Ravens are.
I wonder if Edgar Allen Poe knew the difference between ravens & crows or if raven just sounded and rhymed better in his famous poem 'Nevermore'
Open here I flung the shutter, when, with many a flirt and flutter,
In there stepped a stately raven of the saintly days of yore.
Not the least obeisance made he; not a minute stopped or stayed he;
But, with mien of lord or lady, perched above my chamber door -
Perched upon a bust of Pallas just above my chamber door -
Perched, and sat, and nothing more.
Then this ebony bird beguiling my sad fancy into smiling,
By the grave and stern decorum of the countenance it wore,
`Though thy crest be shorn and shaven, thou,' I said, `art sure no craven.
Ghastly grim and ancient raven wandering from the nightly shore -
Tell me what thy lordly name is on the Night's Plutonian shore!'
Quoth the raven, `Nevermore.'
Have fun birding wherever it may take you and check online for Birding Trail maps.
Charlotte : }
Susan Casey-Lefkowitz said:Charlotte - thanks so much for looking all that up. It is so interesting and now I need to travel somewhere to see ravens! Susan
-
Permalink Reply by Lynne Rbirda Shevlin on -
Susan,
I get crows on the Lower East Side of Manhattan! They're rather small and make a loud cawing sound. I would say they're roughly twice the size of a full-grown starling. While their sound is very distinct, I can't tell the difference (just listening) between them and blue jays. When I was in England years ago, I saw ravens, and they are much, much larger. I believe someone posted that they were 4 times larger, and that seems about right. I wish I could recall the sound they made, but I don't remember hearing them. I saw them at the Tower of London--I'm sure they were planted there to add to the ambiance.
-
Permalink Reply by Laura Erickson on
-
There's a longstanding belief that if the ravens leave the tower, England will fall. There's a full-time Ravenmaster in charge of their care and feeding. During the Second World War most of the Tower's ravens died during bombing raids, leaving a sole survivor named Grip. And the ravens may have been used as unofficial spotters for enemy planes and bombs during the Blitz.
-
Permalink Reply by Lynne Rbirda Shevlin on
-
Laura,
Fascinating info. I hope such a situation as occurred during the war never (or, rather "Nevermore") happens. After I posted yesterday, I noticed the Bird Guide site on the bottom right of the page where we can hear the bird calls, so I did get to listen to the Raven calls. Thanks for the background. Lynne
-
Permalink Reply by Bill Fenimore on -
Susan:
When you look at the bird field guides, note the distribution map for the Common Raven and American Crow. You will not that the statistical probability is very small that your bird is a Common Raven. You could also consider Fish Crow that is found along the eastern seaboard with the American Crow.
Size is a good indicator too. The American Crow is approximately 1/3 smaller (17") that the Common Raven (24"). Other good field marks are the shape of the tail. The Raven's tail is wedged shaped while the Crow is fan shaped, nearly sraight across at the terminal end.
Behavior helps too. Ravens tend to glide when flying, while crows continuously flap their wings. Common Raven is usally seen individually or in paris, not in large flocks. Amercan Crow is more often seen in groups and flocks.
Vocalization is also helpful. The familiar Caw Caw Caw of the American Crow is very different from the hoarse and harsh sounding baritone croaks of the Common Raven.
You will be able to sort out the American Crow from the Fish Crow by vocalization too. The latter Fsh Crow call is a short, nasal cah.
Enjoy the bids,
Bill Fenimore
-
Permalink Reply by Homer Shrader on
-
In your area they are crows. In canada they are ravens and have a different sound altogether. Once you hear a raven it is very easy to tell them apart.
-
Permalink Reply by Laura Erickson on
-
Ravens do appear in the eastern United States, extending pretty far south in the Appalachian Mountains. And this year there is actually a pair nesting in New York City! Here is their range map: http://www.allaboutbirds.org/guide/common_raven/id
Special Feature
Fun Features
© 2012 Created by NRDC and the Cornell Lab.
Powered by
