Monday, October 29, 2012

Civilized Wildlife

American crow- Wikimedia
When I went out to get the paper this morning in our Springfield residential neighborhood, I was greeted by a cluster of raucous crows perching on the barren upper branches of our locust tree.  They were having a private and highly vocal argument among themselves, possibly about the upcoming election.  I walked under the tree, watched them for a minute, standing within 30 feet of them in plain sight, and then walked back into the house as they continued their debate, oblivious to my coming and going.

This would not happen just 20 miles away on Bull Creek.  There the crows keep their distance, warned by their ever present silent lookout high in a tree.  When they explore the trees off our deck they may even sit silently a few feet away.  If they detect the slightest movement in the house they fly off without a single sound of protest.

Some years ago we visited the island camp of a distant cousin in Canada.  He would walk outside his cabin, call out to "John Crow" and a crow would come in to be fed.  He swore that it was always the same crow among the many in the area.  At the time I was dubious- and probably very wrong!

Scary mask? Not to a crow.
There is now good evidence that crows can recognize individual faces.  In 2009, an NPR story by Robert Krulwich described the findings of researchers who wore a caveman mask while catching crows for banding.  They showed that these crows and their neighboring friends would gather around, cawing a warning and even dive- bombing (mobbing behavior) anyone wearing this mask weeks later.  The crows responded even if the volunteers wore the mask upside down (the birds would occasionally turn over in the air in this case!)  This didn't occur with other masks (including a Dick Cheney mask as a neutral example) and occurred regardless of the body build, sex or the gait of the wearer.  (The complete story is at this PBS link.)

A newer study recently reported in  extended their findings.  Over five years the recognition and subsequent mobbing of a mask wearing researcher has spread to the surrounding area.  Not only do the crows remember but they appear to be able to transmit this information to their young! "Even after going for a year without seeing the threatening human, the crows would scold the person on sight, cackling, swooping and dive-bombing in mobs of 30 or more."

Another report  from South Korea in April of this year suggests that a related species, the magpie, also was able to distinguish an individual researcher.  In this case the researcher was climbing trees to study the magpie nests.  The bird would subsequently attack him regardless of what he was wearing.  Another volunteer wearing the researchers clothes passed unnoticed as did the other 20,000 individuals on the campus.

There is increasing evidence that urban wildlife has grown accustomed to humans and are losing their fear of us.  Our Springfield neighbor will walk into her garden to drive the browsing deer down the block, only to have them follow her back down the street as she returns home.  In the case of civilized wildlife, it is becoming clear that familiarity may breed content rather than contempt.

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