Rigor Vitae: Life Unyielding

Tuesday, January 03, 2006

IT'S MURDER, I TELL YA, MURDER!

Three-and-twenty crows dot my back yard. I can hear their gentle caws through my office window. Now and then, I'm startled when one yanks on the rain gutter above me. For a couple of weeks this fall the daily crow count on my property was 57. One day I counted over a hundred. Seems a ridiculous thing to brag about, but the fact is, I had never seen a crow in Salt Lake City until 2001.

Ten years ago, the American Crow (Corvus brachyrynchus) was absent through most of Utah; just three or four populations were isolated in agricultural areas. The current explosion of the species seems to stretch along the metropolitan corridor from Ogden to Provo (about 100 miles). Where these birds came from, I can only guess, but their colonization is not without precedent. Two related pioneers, the Common Raven (C. corax) and the Black-billed Magpie (Pica hudsonia) preceded the crows.

Ravens were always common in the surrounding desert, and as a boy I wondered why they shunned the city itself, but were common urban fixtures in southern California. Twenty-five years ago, the raven invasion started here, about a century after Salt Lake City erupted from the sagebrush desert. It took the birds that long to adapt their behavior to the new landscape. Los Angeles and San Diego are older, and their ravens learned the urban routine first.
The Salt Lake magpie colonization was less spectacular; they always hung around the edges of the city, and seeing one right in town was never that odd, but in the past twenty years they've become as common in the city as outside of it. On a recent summer suburb morning, I watched a young starling's maiden flight end between the incisors of a large Norway Rat. The rodent dragged his squawking prize toward the safety of a hedge, and two young magpies landed nearby, following the fracas across the lawn in hope of a scrap or two—a pair of canny natives exploiting a confrontation of immigrants.

Landscapes constantly change, and organisms change their form to adapt, but behavioral changes often set the stage for morphological adaptation. As another crow searches my rain gutter detritus, I pause from my typing and listen. Annoying as she is to me, she could be making history.
_____________________
upper: STILL LIFE SELF-DESTRUCTING--COMMON RAVEN (1991) Acrylic 30" 20"
lower: CRASH-BARRIER WALTZER--BLACK-BILLED MAGPIE (2005) Acrylic 30" x 22"

5 Comments:

Anonymous Carl Buell (OGeorge) said...

Very nice site Carel. I look forward to comparing notes. Going back over the posts, you write very well.

I've got a soft spot in my HEAD for corvids; they have the endearing quality of making the most innocent act look like a felony.

I'm not sure about Rough-legged Hawks being big arctic kites, but I can't help but wonder how our "anal retentive Swedish Intellectual" would have ordered things if he'd had a concept of deep time and evolutionary change.

9:57 PM  
Blogger cpbvk said...

Thanks, Carl! I'm in eternal awe of that third great Carl, von Linne, and wonder just how far he really was from understanding deep time and evolutionary change.

5:00 AM  
Anonymous Clare said...

The corvids are amongst my favourite birds, and I could never understand why some despised them. The raven has adapted well (being probably the brainiest of a brainy family) to all sorts of environments, and is my constant companion, here in the High Arctic, even in the depths of winter. The arctic or a city seems to present no obstacles to them. I was surprised it took them that long to move into Salt Lake City.

5:55 AM  
Blogger cpbvk said...

Maybe they don't like Mormons. I can't understand people who are creeped out by corvids, either. I've been astonished at the number of people who've reacted negatively to my magpie painting.

6:46 AM  
Blogger Simon Langer said...

Hi there, just wandering the blogosphere and I found your blog. I really enjoy how this all works.

This is one to watch.

Many thanks,

how to birdwatching

10:41 AM  

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