Tuesday, April 21, 2009

The mob

When an enemy approaches, many birds react with a technique called “mobbing.” Crows are famous and vociferous mobbers, ganging up and screaming at hawks or owls.

For years, scientists considered this mostly a method of chasing away predators.

But Eberhard Curio, a German scientist, wondered. He set up a special cage with two blackbirds, a stuffed owl, and a soda bottle. Only Blackbird A could see the owl while Blackbird B could see Blackbird A and the soda bottle. Blackbird A angrily yelled at the owl, while Blackbird B saw only the yelling bird and the bottle, and figured Blackbird A was yelling at the bottle. Blackbird B later taught Blackbird C to fear the bottle, and Blackbird C then taught Blackbird D, and so on.

The curious Curio concluded that mobbing blackbirds were acting as tutors, teaching birds to “know thine enemy.” So the next time you see a dozen crows mobbing a hawk, you may actually be witnessing a big outdoor seminar.

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