[BCNnet] Fw: Study Finds Chubby Birds Fly Better

[judymellin]

There have been a couple of articles similar to this mentioned recently and
I thought folks might be interested in this!

Judy Mellin
Palatine, IL.
----- Original Message -----
From: Dave Bagley <bags@erols.com>
To: BLUEBIRD-L <BLUEBIRD-L@cornell.edu>
Sent: Monday, October 22, 2001 6:44 PM
Subject: Study Finds Chubby Birds Fly Better


> Hello List,
>
> I found the following story featured on AOL and thought it interesting
> enough to post here.
>
> Dave Bagley
> Maryland
>
> Study Finds Chubby Birds Fly Better
>
> By MARGIE MASON
> .c The Associated Press
>
> (Oct. 17) - As skies fill with millions of migrating birds, European
> scientists say the seasonal miracle appears to hinge on a seeming
> contradiction: The fatter the bird, the more efficiently it flies.
>
> The results of their study - involving four birds that were captured as
> adults and trained to fly in a wind tunnel - contradict a central theory
of
> aerodynamics, which predicts that the power needed to fly increases
sharply
> with load.
>
> For birds, apparently, the cost of flying with heavy fuel loads is
> considerably smaller than previously thought.
>
> ``We have measured, for the first time, how flight power changes with body
> mass in a bird and the results were very surprising,'' said Anders Kvist
of
> Sweden's Lund University, the lead author of the study in the latest issue
> of the journal Nature.
>
> Researchers found that red knot wading birds double their normal body
weight
> of 3.5 ounces before making their twice-a-year, nonstop commute between
the
> British Isles and the Russian Arctic. Distance: 3,100 miles.
>
> Another Nature study - this one involving pelicans trained to follow a
> motorboat and a light aircraft - quantified the benefits of flying in an
> aerodynamic V formation, which allows birds to save energy by gliding in
the
> lead bird's air stream.
>
> Flying in formation, their heart rates were as much as 14.5 percent lower
> than flying solo, according to Henri Weimerskirch and colleagues from the
> Centre National de la Recherche Scientifique in France.
>
> Avian researchers who did not participate in either experiment said the
> findings help explain how birds complete arduous migrations.
>
> ``It's always just amazed me to think if we took an airplane and doubled
its
> weight and tried to fly it we couldn't get it to fly, and that's exactly
> what these birds are doing,'' said Brian Harrington, senior scientist at
> Manomet Center for Conservation Sciences near Boston.
>
> Researchers had assumed that sleeker, more athletic birds would have the
> best chance of survival.
>
> The first study suggests that building up fat deposits to be burned as
fuel
> during the migration is more than worth the energy it takes to carry the
> additional weight. Heavier birds apparently use their muscles more
> efficiently.
>
> Just why this is so remains a mystery, said British zoologist Jeremy
Rayner
> of the University of Leeds.
>
> ``A central question that has occupied a lot of us for some time is how
much
> energy it costs the bird to fly,'' Rayner said. ``How does a bird cheat
what
> seems like a fundamental of physics? One day we'll get the answer, but at
> the moment it's not obvious.''
>
> In the study, Kvist said his team studied the red knots flying six to 10
> hours in a wind tunnel. The birds were flown at different body masses
during
> 28 simulated flights. They were injected with a small amount of water
> containing a radioactive element that enabled the team to measure the
amount
> of energy burned.
>
> Harrington said the researchers discovered that the physiology of heavy
> birds is much more efficient than believed.
>
> ``I think it's pretty exciting stuff,'' he said.
>
> AP-NY-10-17-01 1948EDT
>
> Copyright 2001 The Associated Press.
>
>

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