Monday, March 1, 2010

Crows and "Mobbing"

I drove around looking for eagles today.  No, I didn't go to the river.  I headed south and east for a spin through the coulees.

Several Bald Eagles.  No goldens.  Lots of Horned Larks looking for weed seeds along roadsides recently scraped by snowplows.

When I spotted larks, I switched to "electronic mode" in my Prius, rolled down my window and crept up on them.  How close could I get before they'd fly?  Usually - not close enough to get a good photo.

I was playing this "game of stealth" when I heard the raucous "caaawww, caaawww" up the road.  I looked up and spotted a half dozen crows, "mobbing" a Red-tailed Hawk.

American Crow "mobbing" a Red-tailed Hawk
in Maxville, Wisconsin

They screamed.  They dive-bombed.  They did whatever it takes to drive a red-tail away.  Some "mobbers" add defecating and vomiting to the list of "whatever it takes."

Usually, noise is all they need.  Like a police whistle,  "noise" can motivate predators to move on.  Causing a ruckus can also alert other potential prey to the presence of the predator - and invite them to join in on the harassing.

As long as they keep a safe distance, the "mobbers" are seldom at risk.  It's more of an exclamation point at the end of the sentence "we see you, we want you to leave, now!"

Crows, gulls and passerines as small as chickadees will "mob" raptors to defend themselves and protect their nests.  

But red-tails don't prey on crows, and they're not nesting this time of year.  So why spend the energy?

Maybe they're teaching their offspring to recognize predators.  Maybe they're trying to get the predator to drop his meal.  Or maybe they're just having fun.

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