Just like humans, birds too rely on sound to communicate. However, they do not have a ‘language’ in the true sense of the word and instead emit a variety of squawks and chirps to convey different emotions.
Often, birds recognise their mates (or young) by sound rather than sight. Hungry fledglings use begging calls to let their mothers know it is feeding time. Alarm calls, flight calls for flight coordination, and warning calls are other sounds emitted frequently by the adults.
In addition to all these regular calls, some male birds develop elaborate songs intended to attract the females. Some feathered pairs keep in touch through duets; the female bird answers the male’s call so promptly, that the duet sounds as if a single bird has sung it!
Believe it or not, but birds can pick out the call of a potential mate among thousands of other birdcalls and other natural sounds.
A new study carried out by an American University shows that songbirds are perfectionists – they rehearse their melodies even in their sleep. The new finding emerged from a study of the electrical brain activity of a species of Australian songbirds called the zebra finches.
The research team discovered that the activity in the brain of the birds that were asleep was similar to the brain activity produced when the birds were awake and singing.
The team used tiny recording devices to measure the activity of individual brain cells in four zebra finches both when they were singing and when they were asleep.
When the recording was played back the nerve cells’ activity (of the sleeping bird) was identical to that which accompanied singing, although the bird produced no sound.
Apparently the bird stores a song after hearing it, then rehearses it later in its sleep. Scientists now believe the birds ‘dream of songs and tunes’ to help them master the fine art of singing and that sleep plays a key role in the learning process!
It is commonly known that many songbirds learn to sing listening to adult birds of the same species. However, if separated from the adults, the chicks develop unintelligible warbles instead of normal song patterns.
If taught the song of an adult of another bird species, the chick grows up singing the new song and passes on the foreign song to its chick.
For instance, researchers carried out an experiment in which a male bullfinch was raised by a female canary. The bullfinch soon learned the canary’s song and when it was later mated to a female bullfinch, Mr. Bullfinch taught his children the canary’s songs.
Early last year, a British survey of London’s songbirds revealed that the city’s birds are losing their melody. The research team noticed that birds like the cuckoo and the woodchuck had harsher songs with fewer notes and tones.
They soon realised that birds could hardly hear one another, over the traffic din; as a result they had difficulty in learning songs and communicating with potential mates.
And instead of copying the sweet notes of the adults, chicks were imitating sounds, which they heard most often – namely blaring car horns and beeping cellular phones!