<ring rolls in with slushy sidewalks, dripping rooftops, and blue skies, birds begin to sing again. But, what do their chirps, tweets, and twitters really mean?
First of all, not all bird sounds are created equal. Only one suborder of birds, Passeri, known more commonly as songbirds, can actually produce “songs.” These birds have specialized syrinxes, which are the bird version of the human vocal chords. While other birds also have syrinxes and can produce vocalizations, they are not as complex and melodic sounding. Unlike the human vocal chords, songbirds’ syrinx is in contact with two separate inputs of air, so it can vibrate at two different frequencies and therefore produce multiple notes at the same time.
When you hear the resonant melodies, they are usually coming from males singing to find mates and defend their territory. Jesse Ellis, Director of Coe Wilderness Field Station at Coe College, explains that not only do these types of songs differ from one another, but they also show different patterns of regional dialects. Mating songs are ubiquitous across large regions, which likely serves the evolutionary benefit of appealing to a larger number of potential mates. In comparison, territorial defense calls vary highly between areas. This variability is likely due to the lack of an evolutionary selective pressure to maintain similar calls.
While you take a walk in the Arb this spring, keep an ear out for the American Robin, Palm Warbler, Eastern Bluebird, Blackburnian Warbler, and other songbirds. If you’re looking for more information about where to find these songbirds and learn their calls check out the Cowling Arboretum website.