Nightingale, nightingale, how do you sing?
Who doesn’t love to wake up to the refreshing chirping of birds? Birdsongs, especially those of a nightingale, have been immortalised in literature. But very few of us know how and why birds whistle or vocalise. Here is a quick rundown on the way birds sing and the different types of sounds produced by them.
Song learning and production
The physiology of bird vocalization is unique in the animal kingdom. The sounds produced by them can be simplified further. A call is a short vocalization produced during the breeding season. A song, however, is a combination of a series of syllables to produce single notes. Each bird has its song repertoire, or a collection, specific to its kind. Bird song is a language in itself. They can be decoded to identify a species and understand its behaviour.
Ranging from a variety of sounds like chirps, rattles, whistles, trills, croaks, and drums, birds produce captivating sounds, similar to the distinctions in human voice. Birds possess a special organ called the syrinx located at the top of their windpipe for producing sound. The air comes into the windpipe, the inner membranes vibrate and produce vocal sounds. The syrinx has two bronchial tubes to allow most birds to sing with two pitches at once. Songbirds learn their songs and perform them using this voice box.
Why do birds sing?
The language of birds is similar to the way humans communicate through words and gestures. Apart from producing a melodious tune, birdsongs are an important part of their survival strategy. Some species sing more vibrantly at different times of the day. Here is why.
Marking territory: Birds sing to define territories and specifications of food, water, shelter, and nesting sites. This also includes the quality of land that would further define their needs.
Finding mates: Most singing birds are male. They use a variety of notes and sounds to demonstrate skill and attract female birds. There are instances of song duetting between birds as well. It is also believed that a more complex song is most desirable by females because it shows the birds' ability to survive.
Signalling an alarm: Sharp, penetrating sounds produced by birds can be indicative of a warning sign. These calls are made in times of danger or when a bird feels threatened. Short but deep sounds can be heard at great distances.
Calling for help: Small birds produce short chirps to attract their mother’s attention. The intensity of the call is low but it can be heard within the nesting area. Such calls also involve the flapping of wings, which produces sounds.
Announcing their flight: Birds make use of specific sounds at the time of flight. The sound of a flight call is different from the usual call of a bird. Most songbirds migrate during nighttime. So, their flight calls can be heard during the dark of the night.