Someone put the idea in my head that it’s not only birds paying attention to the sounds made by other birds, but that any number of other species might rely on bird alarm calls to know when predators are in the area. When birds aren’t making alarm calls, they’s doing their song thing. And if birds are safe, monkeys are probably safe too. So perhaps, then, when we as humans hear birdsong we have an adaptive response toward calm and focus on immediate subjects.
It at least seemed worth a try, so I got some mp3s of birdsong from a friend and played them during one of my classes today.
Student: Hey, are those real birds?
Me: Yes, they’re real birds.
Student: Oh, I wasn’t sure if they were coming from the computer.
Me: They are coming from the computer.
Me: It’s a recording of real birds.
Not exactly a conclusive result, but perhaps I need to refine my experimental method.