Nations form alliances to protect each other from attack. People also do this, especially males, to defend each other. That’s where the phrase “I’ve got your back” comes from, meaning one person will watch out for the other, most often in difficult situations.
Now imagine that you are a 5-inch tall bird like the chipping sparrow, which lives throughout the western United States. Every morning when you get up, you sing a song that tells your neighbors, “Here I am!” It’s how the birds claim territory.
Now imagine that a big macho male chipping sparrow moves into the neighborhood. When it sings its song saying, “Hey, I’m the new guy,” the surrounding male birds are worried. They don’t want to share their neighborhood’s resources. So they attack, forming alliances like nations and people to rid their neighborhood of the new bird.
Scientists documented this behavior by using a fake bird and recorded bird sounds to see how real birds would react. The result was behavior that has rarely been recorded in birds.
What the researchers found was that the faster the new bird trilled, and the more manly it sounded, the more likely neighbors were to rush over to try and get rid of the new guy.
The scientists figure that the birds would rather have a lousy, weak neighbor than a tough one that might be more competitive.
— Brett French, Gazette Outdoors editor