The science of birdsong

Reader's Digest Editors

It's a sound we're all familiar with—but why do birds sing? And how do they get that perfect pitch? All your questions answered. 

Do songbirds have perfect pitch?

a songbird perched on a branch

Songbirds do indeed have perfect pitch. A scientific study has shown that various songbirds, including zebra finches and white-throated sparrows, are much better at determining, distinguishing and remembering isolated pitches than human beings or rats.

Even when human subjects were provided with a second sound for comparison, they were far less skilled at determining its pitch than songbirds.

Hardly surprisingly, rats appear to find this kind of test very difficult. What it is that causes the differences in hearing ability has not yet been thoroughly researched. The company of conspecifics seems to play a role in the development of hearing in birds since birds reared in isolation seem to do less well in experiments of this kind.

Early experiences with music play a role in human beings. Most babies have perfect pitch, and this is usually preserved if they are given music lessons at an early age. Speaking a tonal language such as Mandarin—where words can have different meanings depending on tone and pitch—also help to develop perfect pitch. 

 

How do birds know when to start their song in the morning?

a black bird prepares to start the dawn chorus

Every species of bird wakes up at a very particular time in the morning and begins to sing. This is because each species has its own specific waking stimulus, which is linked to the brightness of the dawn light. These waking times are so precise that we can even tell the time by them—a phenomenon that has given rise to phrases such as "up with the lark" and "to rise before cockcrow".

In central Europe, the first to sing is the common redstart, which starts precisely one hour and 30 minutes before sunrise. This bird is followed at intervals of between five and 10 minutes by the robin, the blackbird (above), the cuckoo, coal-tit, chiffchaff and chaffinch, and then at 20-minute intervals by the sparrow and the starling.

 

Is birdsong learnt or innate?

birds teach their chicks to sing

Just as human beings have to learn to speak, so birds also have to learn how to sing. They do this in several stages.

First, they practise tones and sounds, which is comparable to the babbling stage in human language development. During the second stage, the birds practise their song for eight to nine months, until memory and practice match up. The singing is strengthened and polished during the final phase.

Humans and birds both appear to go through a phase when the brain is particularly receptive to learning language or song. This is why birds have to hear other birds of their own species sing while they are still young, otherwise, they won’t be able to produce much more than a whistle later on.

 

Do nightingales sing only at night?

a nightingale sings during the day

Although nightingales got their name as a result of their nocturnal singing, not all nightingales sing at night. Generally, both males and females sing during the day. The nocturnal song is used mainly for mating purposes, which is why only bachelors sing at night.

After he has succeeded in attracting a female, the male nightingale falls silent immediately darkness falls and doesn’t start his song again until dawn. This is when he will need to make his presence felt by any possible competitors for his female’s attentions. This is vital because male nightingales tend to be in the majority, and each season about half the males are left without mates.

 

Do birds sing with an accent?

a robin sings with an accent

Birds don’t all sing the same songs, not even within a species. The song of a robin in London will be quite different from that of a robin in Paris or Berlin. Although the members of each bird species share a vocabulary of sounds, dialect differences are quite common.

Among yellowhammers, a distance of a few hundred metres is sufficient for the birds’ song to change. The individual dialects are not innate but are learnt while the birds are still chicks in the nest—just as children adopt the dialect of their parents. The young birds always sing as well or as badly as their teachers, and because the adults on which they model themselves vary in style and talent from region to region.

Some bird species have more than 60 dialects, and many singers can be described as multilingual. Males that master several dialects have a better chance of finding a mate since females prefer mates from the same dialect family. Bird dialects also help to drive evolution, because different songs lead to the formation of groups. This can cause the formation of new sub-species and eventually even completely new species, as happened with the marsh warbler and the reed warbler.

 

In which seasons do we hear the greatest amount of birdsong?

robin singing

Birds are seasonal singers. We only hear intensive, many-voiced bird concerts between spring and high summer. This is the time when birds are looking for mates, and when the males aim to impress the females with their song, which simultaneously serves to mark out their territory for the benefit of rival males.

However, even after they have found a mate and the chicks have hatched, male birds continue to chirp and twitter, because this is the time when they are showing their offspring how to sing. The young males have to learn how to attract females when they are mature, and the young females must discover what song it is they have to pay attention to later on.

When the chicks have left the nest, the male’s sex hormone levels fall and the birds cease to sing. Moulting then takes place, a process which will drain them of energy.

 

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