By Susan Rothrock Deo Photo: Northern Mockingbird. R. Hagerty, USFWS
Tweedle-dum, tweedle-dee; Richard, Richard; cheer-up, cheer-up, cheer-up! the mockingbird seemed to sing this morning. It’s fun to make up onomatopoeic words for birds’ songs (words that sound like what they sing). Experienced birders can identify a species just by hearing its song. Some use words or phrases to help them remember, like the Eastern Towhee sings, “Drink your tea.”
Our northern mockingbird (Mimus polyglottos) is quite a prolific songster. Mockingbirds belong to the thrush family—like the robin and wood thrush—many of which are beautiful songsters. Here in SoCal mockingbirds are one of the earliest birds to start singing in the morning and one of the last to stop at night. This spring they seem especially vocal, or maybe it’s because we are home more. Not only do they have tons of their own songs, but they also “mock” other birds, or sounds they hear like lawn mowers and car horns! Listen to this one imitating a car alarm. Mockingbirds can learn new songs throughout their lives but not all birds are able to do that.
There are two types of bird vocalizations. Calls are relatively simple, used as alarms or to keep a flock intact. Songs are more complex and melodious, associated with the bird’s territory, courtship and mating. Bird song is most developed in the Family Passeriformes, the aptly named “songbirds.” In most species it is the male that sings, usually from a prominent perch like the top of a tree or a pole. In some species, like our mockingbird, both sexes sing. Mockingbird males sing more, and young males the most.
How do birds learn to sing? A bird’s brain isn’t exactly like a human brain, but it is much more complex than scientists originally thought. Distinctive areas function for different stages of song development. Baby birds first listen to their parent’s vocalizations and memorize the basics. Then they practice (like toddlers babbling) until they can accurately match the memorized “template.” Some add their own special flourishes. If young birds have no adult model to follow, their songs are erratic and unlike others of their species. Scientists think the best songs win: females are attracted to males with the most beautiful songs.
Our (mammals) sound-producing organ, the larynx, is at the top of the trachea (windpipe) while the birds’ organ, the syrinx, is at the bottom. The syrinx is surrounded by an air sack. Membranes resonate as the bird forces air over them. They control the pitch by changing the tension on the membranes and the volume by changing the force of exhalation. Birds can control the sides separately, allowing some species to sing two different notes at once.
Want to learn more about identifying birds by their songs? You can start by joining one or more bird walks held monthly in several South Bay parks. Or you can download a free bird application on a computer or smart phone. The apps include recordings of vocalizations as well as information about the bird’s habitat, coloration and size. Several notable apps and websites: the National Audubon Society or the Cornell Lab of Ornithology and their Merlin ID. Listen to a mockingbird sing what you might call a medley of songs here.