365 Urban Species. #053: American Crow

[urbpan]

photo by cottonmanifesto
Urban species # 053: American crow Corvus brachyrhynchos

The crow has a long and storied association with humans. The crow's
black plumage and taste for carrion, along with its legendary
cleverness, has meant that crows and ravens have been taken to be
dieties, avatars, omens, and demons. What they are, truly, are the
largest members of the songbird order. They are thought to be some of
the smartest and most adaptable birds. Recently,
one captive crow became the first non-human animal to craft a tool
using man-made materials.

"True" crows are birds in the genus Corvus which includes birds
given the common name jackdaw and raven, all of which are omnivorous,
pigeon-sized or larger, and black. The crow family, Corvidae,
includes many other birds, including blue jays and
magpies. A great many of these bird species are bold and resourceful,
making them good candidates for urban species.

American crows are the most common crows in North America, followed by
the common raven (C. corax), which is found throughout Eurasia
as well. Ravens are absent from southern New England, and much of the
plains states and provinces, but are urban animals in such cities as
San Francisco. Fish crows (C. ossifragus) are found all along
the east coast, feeding along salt and fresh water shores. Fish crows
can be reliably distinguished from American crows only by their voice
(fish crows have a more nasal caw).

Carrion feeding animals of all kinds have learned to appreciate the
highways as a source of food. Other human-derived sources of food for
crows include garbage dumps, gut piles left by hunters, and (though it
is gruesome, it is historically significant) battlefields. Crows
famously visit crop fields, notably grapes and corn, but the fact that
they prey on insect and rodent pests mitigates their own pest status.

Crows are drawn near cities in the fall and winter in huge numbers,
known as winter roosts. Thousands of birds gather in large trees just
outside of city centers. These groups derive safety in numbers, as
well as safety from city-shy predators, such as great horned owls.
The radiating warmth of the asphalt probably helps to attract crows to
metropolitan roosts.

West Nile virus had a huge impact on crows over the past five years. We observed a crash in the Boston area crow population in 2002. We have seen more crows this year than last year, but there are still far fewer around than there were in 2001.




Northwestern crow Corvus caurinus Seward, Alaska.

Comments

[morrigandaughtr.livejournal.com]

Hey, thanks for this.

[urbpan.livejournal.com]

You're welcome! I hope you think I did them justice.
I was nervous about it--they are absolutely my favorite, so writing anything at all would seem inadequate to me.

[morrigandaughtr.livejournal.com]

Big justice. :-) Didn't know they were your favorite, too.

[ankhanu.livejournal.com]

Seems fine to me :)
Despite most people seeing them as vermin, I love crows too; I probably spend more time watching (and interacting) with them than any other bird. They're utterly fascinating and beautiful.

I'm rather glad that the West Nile issue didn't really spread to Nova Scotia, there were maybe half a dozen dead birds found or so, but, our crow (and other passerine) populations are still intact. I couldn't imagine what it'd be like if they were to disappear.

[cottonmanifesto.livejournal.com]

You didn't write anything about them all being dead. :(

I saw a large group (12-15 individuals) fly over longwood this afternoon!

[ankhanu.livejournal.com]

It's saddening that that is a large group... that should be a fairly standard flock size.
While I was helping my father cut down trees last fall I looked out over the channel between the Bras d'Or Lakes and the Atlantic and noted a large flock of crows flying north along its length; there must have been hundreds. It was quite awesome seeing that many birds. The flock was large enough that you couldn't see the whole thing, the lead birds would disappear into th edistance as more birds would appear from behind. The flight pattern was pretty diffuse to non-existant, so it wasn't like seeing, say a flock of really big starlings or something, but just a steady stream of birds.

[cottonmanifesto.livejournal.com]

It is extremely pathetic that 12-15 is a large group. Mostly, I'll see either a singleton or a group of 3-5. It's at the point now where I'll hear a crow and go "oh! a crow!" like it's something special (which it is). There was an article in our local paper about the crow 'problem' in the fall of 2001, now you're lucky if you see one crow a week - sometimes I don't even see that. :(

[artemii.livejournal.com]

i always thought it was amusing that Raven, the trickster amongst most of the tribes in the northwest of north america (including the one with which i lived), discovered humans in their cosmologies. (Raven found them stuck in a giant clam shell and pried it open so they could come out into the world)

[lizblackdog.livejournal.com]

YAYY CORVIDS!!!

I didn't realise your crows were a different species to ours. (Ours are C. corone). Learn something new every day.

[urbpan.livejournal.com]

And if I'm not mistaken, the same species occurs all across Eurasia, but the further east populations have gray markings?

[lizblackdog.livejournal.com]

Hooded crows, yes: http://www.rspb.org.uk/birds/guide/h/hoodedcrow/index.asp

They were the standard issue crow in Iran when I was a kid. They're more aggressive than carrion crows, but basically the same thing.

[harrietbrown.livejournal.com]

The article about Betty bending the wire into a hook was fascinating. Thanks!

[urbpan.livejournal.com]

You're welcome! That story makes me very happy.

[bunrab.livejournal.com]

Ravens are absent from southern New England, and much of the
plains states and provinces, but are urban animals in such cities as
San Francisco.
And, of course, Baltimore!
Really, I think we've got almost all the corvids here, I don't know how they keep from trespassing on eachother's niches, but they're all here. The city is completely raven-crazy, mostly because of Poe, and that's what the football team is named. And the team colors are black and purple.
::BunRab wanders off again, singing the Alfred Deller version of "Three Ravens"::

[ex-wellread.livejournal.com]

I read that if there were no crows, that the world would be filled with rotting animals. I appreciate them for the fact they are "street cleaners". There are plenty of them and thats why I mentioned them as ordinary birds. Something I see daily. But because of their eating habits, they are "special".

[cottonmanifesto.livejournal.com]

Their absence is definitely noticed when there's roadkill around - nobody's there to eat it!

[aemiis-zoo.livejournal.com]

Stupid question (especially from me) are crows and ravens 2 different species of birds?

[ankhanu.livejournal.com]

Yes. They're both in the same genus (Corvus), but are different species... of course, that's referring to the crows/ravens in North America anyway, there may be birds referred to as crows and ravens elsewhere that aren't in the same genus. That's the fun of common names versus taxonomic names :)

Common crow - Corvus brachyrhynchos - medium sized black bird, relatively sleek with squared tail; caws
Northern Raven - Corvus corax - larger medium sized black bird, bulky, shaggy around the bill, wedge-shaped tail; call is more like a hoarse croak

There are other crow and raven species in North America (2 more crows and another raven), but these are the ones generally referred to.

[gemfyre.livejournal.com]

Australia has a few species of Ravens and a few species of Crow. All of the Corvus genus.

[gemfyre.livejournal.com]

I read somewhere about crows... in Japan I think.

Anyway, they were given whole walnuts. And it was noted that they'd wait at traffic lights until the lights went red. Then they'd place the nuts in front of the tyres of the cars and step back when the lights went green. When the lights went red again they'd grab the cracked nuts.