Subject: Homing Pigeons Concorde Causes Lost Pigeons? (fwd)
Date: Mar 20 14:48:37 2000
From: Deborah Wisti-Peterson - nyneve at u.washington.edu



hello tweets.

here is something that you might be interested in reading ...

regards,

Deborah Wisti-Peterson email:nyneve at u.washington.edu
Department of Zoology, University of Washington, Seattle, Wash, USA
Visit me on the web: http://students.washington.edu/~nyneve/
<><><>Graduate School: it's not just a job, it's an indenture!<><><>


---------- Forwarded message ----------
Date: Mon, 20 Mar 2000 10:59:50 -0800

>
> By Discovery.com News
>
> March 17, 2000 -- Although it helps humans move across the globe
> quickly, the Concorde may be responsible for making thousands of
> homing pigeons arrive home late.
>
> As reported in this week's issue of New Scientist, California
> geophysicist Jon Hagstrum has found evidence that the supersonic shock
> waves caused by the jet may prevent pigeons from hearing a
> low-frequency sound that helps the birds find their way home.
>
> Scientists have shown that the pigeons have an innate "compass" that
> enables them to navigate by using Earth's magnetic field and the sun's
> position. However, in order to reach their destination, the pigeons
> must also have a "map sense," or a mental chart linking their starting
> position with their destination.
>
> "Nobody has been able to understand how they do that," Hagstrum told
> New Scientist.
>
> Some researchers believe the map sense is based on infrasound --
> extremely low-frequency sounds audible to birds, but not to humans.
> Waves exert pressure on the seabed, causing the land to shake, which
> in turn radiates infrasound into the air. According to Hagstrum, steep
> hillsides cause the sound waves to move horizontally, possibly
> creating beacons for birds to travel by.
>
> Hagstrum became intrigued by the effects of supersonic planes when he
> learned that during pigeon races most of the birds are late or
> permanently lost. In 1997 alone, a third of the 60,000 British pigeons
> released in Nantes, France, did not return to England and the rest
> arrived late.
>
> Hagstrum studied four pigeon races and found they all had one thing in
> common: The pigeons had to cross the path of the Concorde's infrasonic
> shock waves during their trip.
>
> To test his theory, Hagstrum compared the birds predicted routes home
> and departure times of each of the races with Concorde data for the
> same time. In each race, the birds would have entered the cone-shaped
> shock wave, possibly temporarily or permanently deafening the pigeons
> to the infrasonic beacons.
>
> Bird navigation expert Bob Beason of the State University of New York
> in Geneseo said Hagstrum's work is intriguing and follows current
> pigeon navigation theory. "The idea that pigeons might use infrasound
> for orientation has been around for a while," he told New Scientist.
>
> Beason said Hagstrum has more work to do to prove that the Concorde is
> to blame for lost pigeons.
>
>
> 1. http://www.discovery.com/
>