This is Bird Note.

Brown-headed cowbirds have a sneaky approach to parenthood.

They lay eggs in the nests of other songbirds, and the songbird hosts often raise the cowbird

chick as their own.

It's called nest parasitism.

It exploits a songbird's tendency to care for any young in the nest.

But sometimes the hosts catch on to the cowbirds' ruse and throw out the odd looking egg.

And when that happens, the cowbirds have a way of dealing with this kind of disrespect.

The cowbirds sometimes retaliate by destroying the hosts' other eggs.

Scientists call this mafia behavior, likening it to organized crime groups, enforcing their

demands on unwilling business partners.

In one study of cowbird mafia behavior, host parents that accepted the cowbird eggs

fared better than ones that resisted, raising more of their own young.

For the hosts, the risk of losing all their eggs at once outweighed the cost of having

their chicks compete with the cowbird chick.

It seems the cowbirds just want a smoothly running operation.

No funny business.

A little show of force now and then could help keep their hosts in line.

For Bird Note, I'm Michael Stein.

Today's show brought to you by the Bobbelink Foundation.