Bird species and their songs

There is not just one "song language of birds", but as many as there are species of birds - thousands!

Species-specific songs

With song, members of each species communicate only with other members of their own species. Indeed, one of the more elementary functions of song is to enable females to recognise males as being of the “right” species.

Humans also distinguish unseen birds by their species-specific songs. Gilbert White, the gentle curate of Selborne and the father of English natural history, was the first to sort out from one another three very similar-looking birds by their songs: the willow warbler, wood warbler and chiffchaff. That was 250 years ago. Today in tropical forests virtually the only way to know which birds are about, is to know their songs and calls.

Individual male songs

Song is not only specific to each species. In some species at least (and perhaps in many) each individual male singer can be identified by other males by his song. Make a recording, convert it via a sonagraph into a “voice print” and one has, in effect, a finger print, a sound signature. Not only can we tell individual cocks apart in this way - so can the cocks themselves by listening to one another.

This was first proved in the case of a New World warbler called the ovenbird. Imagine bird A settled in its territory, with three neighbours 1, 2 and 3. All four are singing normally and none worries unduly about his neighbours. If, however, you introduce the taped voice of another bird, B, (previously recorded from a territory several miles away) playing it back within earshot of A, then A instantly recognises the “bird” as a stranger and at once investigates. Individual signature songs and the ability of ovenbirds to recognise them, functions to save territory holders time and energy. Once identified there is no need to investigate birds who are “next door”, because experience has shown how they usually operate.

This is not to suggest that neighbours are necessarily well behaved. Bird 1 could well set out to annexe part of A's territory, but A would presumably notice him visually or detect that his song sounded clearer. Thus it is important to know that your neighbour is keeping - or not keeping - his distance. The loudness of his song will give a crude measure of his distance.

Song matching

To help territory holders of certain species to monitor the behaviour of neighbours, a special technique has evolved. Certain species like the chaffinch and the great tit do not sing exactly the same phrase each time they sing. Each individual has a repertoire of several phrases, many of which it shares with its neighbours. If you are in the presence of either of these species it soon becomes noticeable that each individual which initiates a bout of singing is almost invariably answered with the phrase most closely resembling the one that he himself used. The counter singer, in other words, matches the song he hears.

Why? Well, the suggestion is that by this means the answerer (and for that matter the initiator) can best judge the distance that separates the two. Each knows what that precise phrase sounds like to himself as he sings it, and can therefore, if the same phrase is used back, make the best possible comparison, determining the degree of degradation in the signal and thus the distance of the signaller.

It may sound a little far-fetched, but it is certain that song-matching takes place, and this is one plausible explanation.

  • Jeffery Boswall
  • Jeffery Boswall (1931-2012) was a natural history broadcaster, film-maker and producer. He is best known for his radio and television work with the BBC Natural History Unit. His notable titles include Animal Magic, The Private Life of the Kingfisher, and Wildlife Safari to Ethiopia. Jeffery co-founded the National Sound Archive's wildlife section with Patrick Sellar in 1969.