WASHINGTON, June 4, 2008

Makeup Turns Birds From Scrubs To Studs

Research Shows Darkening Male Birds Made Them More Attractive, Upped Testosterone Levels

  • Natural-colored New Jersey barn swallows, like those shown above, showed an increase in testosterone after having their breast feathers darkened with a marker, according to recently released research.

    Natural-colored New Jersey barn swallows, like those shown above, showed an increase in testosterone after having their breast feathers darkened with a marker, according to recently released research.  (AP Photo/Marie Reed)

(AP)  A little strategically placed makeup quickly turns the wimpiest of male barn swallows into chick magnets, amping up their testosterone and even trimming their weight, new research shows.

It's a "clothes make the man" lesson that - with some caveats - also applies to human males, researchers say.

Using a $5.99 marker, scientists darkened the rust-colored breast feathers of male New Jersey barn swallows, turning lighter birds to the level of those naturally darkest.

They had already found, in a test three years ago, that the marked-up males were more attractive to females and mated more often.

This time they found out that the more attractive appearance, at least in the bird world, triggered changes to the animals' body chemistry, increasing testosterone.

"Other females might be looking at them as being a little more sexy, and the birds might be feeling better about themselves in response to that," said study co-author Kevin McGraw, an evolutionary biology professor at Arizona State University.

McGraw said the findings are surprising, in part because the hormonal changes occurred after only one week.

The study was published in Tuesday's edition of the journal Current Biology.

In the 30 male barn swallows who were darkened, testosterone was up 36 percent after one week, during a time of year when levels of that hormone would normally drop.

At the same time, testosterone levels in the 33 birds that didn't get the coloring treatment fell by half, said lead author Rebecca Safran, an evolutionary biology professor at the University of Colorado in Boulder.

"It's the `clothes make the man"' idea, Safran said. "It's like you walk down the street and you're driving a Rolls Royce and people notice. And your physiology accommodates this."

Before you feel superior to these birds, Safran cautioned, people's mating systems are more similar to birds' than we might like to admit.

Barn swallows are "socially monogamous and genetically promiscuous, same as humans," she said. "There are some interesting parallels, but we do need to be careful about making them."

In people, hormonal changes have been observed after changes in behavior. A 1998 study found that loyal male fans of sports teams experienced a 20 percent rise in testosterone when their teams won.

The researchers aren't certain how the testosterone boost happens. It could be that because of the darkened color, the birds mate more often and that changes their testosterone levels.

It could also be that because of the darkened color, other males think the pecking order has changed and that boosts the darker swallows' hormone levels. Or it could be both. The authors said figuring out which theory is right is the next step.

The birds' weight loss is more easily explained, Safran said. The more macho swallows could be spending more time mating than eating or working off the calories, she said.

Most of the time it's the hormones that change the behavior or appearance, but this work shows "it can go more than one way," said study co-author James Adelman, a Princeton University researcher.

"It certainly is a very new and interesting finding," said Cornell University psychology and neurobiology professor Elizabeth Adkins-Regan, who had no role in the study.

© MMVIII The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.
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by beehive21-2009 June 6, 2008 12:23 AM EDT
Great research, dress your but up, if you want some action , fools.
Reply to this comment
by heero2020 June 4, 2008 9:54 PM EDT


Perhaps they''re just getting high off the fumes.
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by rf35 June 4, 2008 3:46 PM EDT
Why are these scientists messing with natural selection? If they have nothing better to do than color barn swallows, send ''em my way...I got some work for them.
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by sistatee-2009 June 4, 2008 1:49 PM EDT
Female swallows still prefer a male with money.
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by rational_1 June 4, 2008 1:26 PM EDT
I just magic markered the entire front of my T-shirt - it ain''t working! This idea is for the birds.
Reply to this comment
by msay3 June 4, 2008 1:23 PM EDT
hope my story don''t make you cry,
But this birdie flew too high;
He flew from his old Missouri home.
He fell right into the city ways, like dancin'' in cabarets,
From party to party he would roam.

Poor little swollow
Walkin'', walkin'', walkin'' to missouri
He can''t afford to fly.
Got a penny for a Poor little swollow
Walkin'' walkin'' walkin'' to missouri
Got a teardrop in his eye.

Don''t mess with the birds...LOL
Reply to this comment
by downsteamjim June 4, 2008 12:48 PM EDT
It''s called the ''Obama effect''.
Reply to this comment
by jetlizhan June 4, 2008 12:27 PM EDT
oh great - now we''re pimping out our wildlife - leave the birds alone pu-leeeeeeez!!!!!!!!!!!!!
Reply to this comment
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