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Wednesday, October 19, 2016

How to Tell Apart a Crow From a Raven





My latest: Crow and Raven: A Comparison of Silhouettes
Watercolor on 16 x 12" illustration board. 


I don't know why, but I get a kick out of identifying things in the natural world. Just as some people can rattle off the names of their favorite football players or film actors, I enjoy knowing the names of plant and animal species. If I come across a tree in a park that I don't recognize, I'll make a point of noting its leaves, bark, and so on so I can look it up later.

I think it's because names give me a starting point to learn more, to understand. I liken it to this: Say you're are in a room with a bunch of strangers at a skiing lodge in, oh, say, Norway. As an outsider, these Norwegians might look rather the same: tall, blond, and athletic. They're just an anonymous, lutefisk eating crowd. But once you find out their names, you start paying closer attention to them. You find differences that make each individual unique. You learn that Olaf is the only one in the room with deep brown eyes, or that Ingrid is a strict vegetarian. Once introduced, you begin on a journey to know them; and, if you are fortunate enough, you may even become good friends.

So it is with “Crow” and “Raven”. Or even more particularly, the American Crow (Corvus brachyrhynchos) and the Common Raven. (Corvus corax). Both hail from the same family and genus (Corvidae, Corvus) and at a glance can appear nearly identical.

SIMILARITIES

Shiny black feathers
Black bill with nostrils partly covered with feathers
Black legs and feet
Dark brown eyes in adults, grayish-blue for juveniles
Omnivorous – will eat just about anything
Both are known mimics and therefore can make similar sounds
Very intelligent, even recorded using tools
Found in open fields, forests, and wherever people are found


DIFFERENCES*


American Crows

-- Are somewhat smaller; just a bit larger than a dove
-- Bill is shorter and slimmer
-- Typical call is a sharper and higher: “Caw! Caw!”
-- Spread tail in flight is more fan-shaped**
-- Tends to gather in larger groups than ravens
-- Will mob a hawk or eagle in their territory, cawing and swooping at the intruder
-- A bit more restless when perched, flicking tails more for balance
-- At close range, flapping wings are silent
-- Rarely if ever soar on thermals

Bonus fact: the tongue-in-cheek collective noun to describe a flock of crows is a “murder”.



Common Ravens

-- Can be considerably larger, up to the size of a hawk
-- Bill is longer and thicker
-- Adults have a longer ruff or “hackle” of frontal neck feathers
-- Typical call is softer and deeper: “Gronk” or “Gaw”
-- Spread tail in flight is diagnostically more diamond or wedge shaped**
-- Tends towards smaller groups, frequently found in pairs
-- Will more likely escort a hawk or eagle out of its territory than mob it.
-- Overall more calm, sedate behavior when perched
-- At close range, flapping wings are heard to make a distinct whooshing sound
-- Can be seen soaring on thermals

Bonus fact: the tongue-in-cheek collective noun to describe a flock of ravens is a “conspiracy” or an “unkindness”.


Once you get to know these two species, you'll notice these differences – and more. But be careful! Identifying corvids can become habit forming. Especially when you come to the realization that they contain subspecies, as well. Four for the American crow, and perhaps up to eleven for the Common raven.

If you get tired of figuring THOSE out, well....there's always the study of gulls. ;) ***



*NOTE: These are the differences just between the American Crow and the Common Raven. There are additional but lesser-known corvid species in North America, such as the Fish crow, Northwestern Crow and Chihuahua raven (Corvus ossifragus, Corvus caurinus and Corvus cryptoleucus, respectfully) that have their own minor differences.

**Aside from voice, I've found that tail difference is one of the best diagnostics to tell the two apart. However keep in mind that it can be harder to tell when the birds are swooping in to land or are already perched. Also, there are several non-American species of raven and crow that this does NOT work for, such as the fan-tailed raven Corvus rhipidurus of Africa or the little raven Corvus mellori of Australia, which have fan-shaped tails instead of wedge-shaped ones.

*** In some birding circles, becoming involved with the minutia of gull identification has been said to cause mild bouts of insanity.







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