Okay, so scientists have observed this phenomenon with quite a few different kinds of birds. For example, you see this with the bird, a bright red bird, commonly known as a cardino. Cardino lives in trees and other vegetation on the edge of a forest. And during their breeding season, they’re kind of claiming a specific area of the forest as their own. That’s their territory, and foods there belong to them. And they try to keep other cardinos away from this area. Okay, now each cardino has a unique code or song that it sings. And for cardino, here is one of these songs, it knows that another cardino nearby. And researchers have observed that when a cardino hears an unfamiliar song, the song of another cardino that is never heard before. It would become aggressive, it would threaten the other cardino, try to chase it away out of its area of the forest. But what interesting is, when a cardino hears a familiar song, the song of another cardino that established a territory nearby in the same part of the forest. It won’t bother to attack or chase the other cardino away.