[CT Birds] Strong Road Peregrine
boletebill at yahoo.com
Wed Dec 16 22:04:26 EST 2009
The survival value of flocking behavior to bedazzle predators that Dave describes below I've heard described, quite eloquently, as "the geometery of the selfesh herd".
"For those who hunger after the earthly excrescences called mushrooms."
--- On Wed, 12/16/09, David F Provencher <david.f.provencher at dom.com> wrote:
From: David F Provencher <david.f.provencher at dom.com>
Subject: Re: [CT Birds] Strong Road Peregrine
To: "CTBirds" <ctbirds at lists.ctbirding.org>
Date: Wednesday, December 16, 2009, 11:01 AM
Paul I'd be curious to know the age of the Peregrine. Young birds often make these mistakes. The size of a flock often plays a large role in predator evasion as well. The predator, particularly young predators, are often distracted in their chases by the mass of swirling birds. From a birder's perspective think of trying to stay focused on a rare gull at a landfill while it is flying around in a mass of other gulls (if you have ever done that!) It can be maddening to try and avoid following the wrong bird in the chaos. So as a predator tries to keep chasing a target bird, it is making decisions and taking physical actions based on its mental assessment of the prey's actions and where the chaser thinks the prey will be a moment from now. When the attacker's focus unintentionally shifts to a different bird crossing in front of it that is flying at a different speed or in a different direction than the original target, the attacker's decisions and actions
are thrown totally out of sync and the attack fails. Thus the behavior of flocking (or schooling in fishes) increases survival rates for the individual. As for the Peregrine, rather than getting just demerits, the attacker stays hungry and may ultimately pay the highest price for poor hunting success if it doesn't learn better technique and target selection.
Naturally New England<http://naturallynewengland.blogspot.com/>
"12/16 South Windsor, Strong Road - 8,000 to 10,000 Grackles and Red-winged Blackbirds being actively pursued by 1 PEREGRINE FALCON, 1 COOPER'S HAWK, 1 SHARP-SHINNED HAWK and 4 RED-TAILED HAWKS. The falcon spent twenty minutes trying to catch one and never did...demerit to him! There was also a first year Bald Eagle over the river. Other birds included 27 HORNED LARKS and 9 SAVANNAH SPARROW."
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