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Friday, February 10, 2006

Crow behavior

Following up on the crow convention, I decided to try and learn a little more about crow behavior. In the process, I may have found the foremost expert on American crows in one Kevin McGowan of Cornell University. He has been studying crows since 1988, and even tagging and tracking some crows in and around Ithaca, New York.

Regarding the huge congregation of crows I saw the other night:

Crow roosts can range from small scattered roosts of under one hundred individuals to the spectacularly large roosts of hundreds of thousands, or even more than a million crows! A roost in Fort Cobb, Oklahoma was estimated to hold over two million crows (Gerald Iams, 1972, State of Oklahoma Upland Game Inventory W-82-R-10). Most roosts are much smaller, but roosts of tens of thousands are common.

Five things I discovered about crows:

  1. More than a few crows have been found to tear windshield wiper blades off vehicles
  2. The oldest known American crow was 29-1/2 years, but, most don't even make it to one year
  3. While crows go, caw-caw (I already knew that), ravens go, gronk-gronk (I didn't know that)
  4. It is illegal to own a crow as a pet
  5. The poetic term for a bunch of crows is a "murder" (I have a vague recollection of having heard that, perhaps, in grade school reading, but not grade school science)

Whenever the subject of the influx of crows in town comes up, someone invariably remarks that it's due to so much urban sprawl. That is, so many cornfields have been replaced by housing and retail developments.

Dr. McGowan has a couple explanations as to why crows are being found in cities, including, the regulation of crow hunting starting in 1972. "It is possible that this change may have resulted in the decrease of shooting pressure on crows, allowing them to become more tolerant of the presence of people."

His FAQ contains tons of information on crow behavior.

Caw.

Posted by Marie at February 10, 2006 1:25 AM

Comments

The thing about crows that has always fascinated me is that they seem to be very circumspect nesters. Despite being large and prolific birds, I never see them nesting. Where are they coming from?

But I like crows; they're regarded as among the most intelligent birds (which still isn't saying much).
K-

Posted by: Kem White at February 10, 2006 10:19 AM

I've never seen a "murder". The most I've ever seen is about 20 or 30 and they were pestering an owl in my backyard. Several thousand would have me thinking Hitchcock thoughts and two million is a number I can't process.

Posted by: Rob at February 10, 2006 10:36 AM

Kem, After reading the Cornell guy's site, I must admit to a new found respect for crows.

Rob, the morning after Hitchcock's The Birds was on TV, my mom opened the front door to get the paper, and a bird flew into the house. It was only a sparrow. But, still.

Posted by: Marie at February 10, 2006 11:27 AM

Remember the Simpsons episode where Marge builds a scarecrow to get rid of crows in her new vegetable garden. Homer thinks the scarecrow is a prowler and beats it up, thus gaining the trust of all the crows. Marge and Homer are in bed and all these crows are around them. She calls the group something and he corrects her by saying, "It's a murder, honey. A group of crows is called a murder."
They later turn on him and peck his eyes. Dr. Hibbertsays "They weren't trying to blind you they were just trying to drink your sweet sweet eye juices." I love that episode.

Posted by: randy at February 11, 2006 9:14 PM