Turning barn swallows into chick magnets

New research shows that a little makeup quickly turns the wimpiest of male barn swallows into chick magnets, amping up their testosterone and even trimming their weight. The Associated Press reports:

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, at left, 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.

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

-- Alice Short

Photo: Marie Reed/Associated Press