Truly there are few tings as thrilling as beautiful music. Was it not Shakespeare who wrote "If music be the food of love, play on!" Indeed music not only fosters romance, but it can also make us laugh, or cry, or move with the rhythm, or all of the above at once. There are few things which play on our emotions the way music does. Music however is not a gift unique to people. There are other created creatures with wonderful musical talents. Consider the songbirds for example.
Basically bird songs are fancy patterns of sound produced in the throat. Interestingly, these patterns show choices of rhythm and pitch which are very similar to our own musical compositions. Only a small proportion of the 8600 or so bird species actually sing (produce tunes). The true song birds include thrushes, orioles, tanagers, grossbeaks, catbirds, vireos, buntings and warblers. In addition to true song birds, some other birds have calls which are musical enough to be considered songs. These include flycatchers, cuckoos, whip-poor-wills, and lyrebirds.
To produce a song, a bird uses its voice to emit a series of tones of different pitches arranged in a distinctive rhythm. The term 'pitch' denotes the highness or lowness of the sound. This is determined by the number of times per second that the sound making material vibrates. The more vibrations, or the higher the frequency (of vibrations), the higher or more treble is the sound. In our music, for example, convention sets concert pitch for the A above middle C at 440 vibrations per second.
Since the choices in rhythm and pitch made by song birds are so much like our own musical preferences, some human composers have used bird songs as a source of inspiration. One such composer, French organist Olivier Messiaen (b. 1908) actually experimented with bird calls in some of his pieces. The North American hermit thrush (Catharus guttatus), for example, would be an easy source of inspiration. Its song is clear and flute-like, consisting of a key note followed by four or five motifs or phrases set at different pitches. The tunes which this bird sings are based on the pentatonic scale in which octaves are divided into five notes. A scale is a series of tones arranged in a set pattern from low to high (or vice versa). The function of a scale is to provide an alphabet of sounds from which melodies (tunes) and harmonies (chord combinations) can be made. For us, the most familiar pentatonic scale consists of the black notes on the piano. In western cultures, we are actually more familiar with the seven tone scale. Nevertheless we hear the pentatonic scale more often than we might imagine. It is the basis for folk music in the Orient, the Americas, Africa and the British Isles. For example, such Negro Spirituals as "Nobody Knows the Trouble I've Seen." are based on the pentatonic scale. Thus the pentatonic-based song of the hermit thrush is musical to us, as well as, presumably, to fellow thrushes.
Study of bird songs over the past several decades has revealed that bird songs conform to the same laws of musical theory as human compositions. The European robin (Erithacus rubecula) is known for its beautiful music. Each burst of song is made up of four different phrases or motifs. A motif is the smallest unit of musical form. It can be as short as two notes (as in a cuckoo call) and is rarely longer than six notes. A motif usually has a clear rhythmic pattern as well as a clear tune. In some cases it is a harmonic pattern of two or three distinctive chord sounds. The motif is the musical foundation around which a longer composition is built. For example, the four tones at the beginning of Beethoven's Fifth Symphony are used as the basis for the whole first movement. Many popular songs such as George Gershwins "I Got Rhythm" and Vincent Youman's "Tea for Two" are based on short rhythmic motifs which are repeated on various melodic pitches. The North American black capped chickadee frequently sings its familiar motif "chick-a-dee-dee-dee". The European robin, on the other hand, exhibits a repertoire of several hundred motifs, which it uses in different combinations. Since the songs are so varied, scientists wondered what it is that makes these songs so recognizably "robin" songs. In order to find out what rules the songs adhere to, scientists made cuts to robin recordings and recombined various parts. They found that each burst of song (called a strophe or stanza) is made up of about four different motifs. Consecutive stanzas must be different. Moreover in each stanza, all the motifs must be different and if one motif is high pitched, the next must be low (and vice versa). These are fancy rules for a "bird" brain. When scientists composed artificial electronic songs following these rules, robins reacted as if a real competitor had invaded their turf.
Observers have long wondered why some birds sing while others restrict themselves to simple calls like "quack quack". There are no obvious answers. Generally it is only male birds that sing, and their songs are most heartfelt during the courtship season. Some species stop singing after they have found a mate, while others, like the North American robin (actually a thrush), continue to sing whatever their matrimonial status. It does not require a degree in bird behaviour for anyone to notice that the best singing is at dawn. The loudest music, lasting about half an hour, begins shortly after the first glimmer of light. In the evening there is a repeat performance but it is less dramatic than the morning's effort.
Not only do scientists wonder why birds choose to produce sound patterns so similar to human music, but they also wonder why some birds indulge in such lengthy and complicated melodies. Why also do some birds have large repertoires of motifs at their disposal? One thing we have discovered. The musical abilities of song birds seem to be partly genetic and partly learned. Given the choice of two songs, their own or that of a closely related species, young birds raised in the laboratory, will always pick the song of their own species. If they are exposed only to the song of another species, however, they will learn a version of it. One animal behaviourist found that male song sparrows were able to learn some parts of a swamp sparrow's simple song, but the swamp sparrow, on the other hand, proved unable to deal with the song sparrow's elaborate tune. The fact that young male birds learn songs from their fathers and other neighbours means that local dialects are often apparent in bird songs.
There is something about bird songs that reminds the experts of humpback whale music. It is not immediately obvious, but the two types of music are similar. Apparently the recordings of whale songs, speeded up about fourteen times, sound amazingly like bird songs. But humpback whale music is wonderful in its own right. Indeed this whale music is said to be surprisingly beautiful, something like the sounds of oboe, muted cornet and bag pipes. As with bird songs, humpback songs follow specific musical rules. The main differences between bird songs and their whale counterparts is that the former usually last only a few seconds while humpback songs last from about ten minutes to half an hour. Moreover birds typically rest between songs. Whales on the other hand may sing and re-sing their songs for many hours on end. Evidently size confers musical stamina! The experts tell us also that whales sing in key. They are capable of vocalizing over at least seven octaves, but they do not leap from one part of the keyboard to another. Instead they proceed through a song in stepwise musical intervals. American Alan Hovhaness (1911-2000) was a musical composer who paid attention to whale music. One of his most famous pieces was And God Created Great Whales (1969) in which humpback whale recordings provided voice solos for orchestral accompaniment.
Everyone agrees that humpback whale songs are more impressive
than bird songs. As with birds, only the males sing and they do
it only during courtship season. Like birds, whales structure
their music around motifs. A series of variations on a motif constitutes
Their use of themes is similar to that found in some of our musical compositions. Firstly the theme is sung, elaborated upon and then a return is made to the original but now slightly modified theme. This construction is called, in musical theory, the A-B-A form of composition. Typically there are several distinct themes, up to six, in a song. But old songs become boring.
Over a season, whales gradually change their song. Since all sing the same song, they must all agree on the modifications. After a rest of about six months, the whales burst forth into song again and all remember the old song, even without practice over that long interval. Their memories must be phenomenal. Now however, as they begin to sing again, the humpbacks change the details. After several seasons, the song is completely different. Besides these whales, only man has the capacity to change his speech patterns. We vocalize to communicate, but what about the humpback whale? Why does he go to all the trouble of singing, and modifying, his elaborate songs?
The experts agree that neither birds nor whales actually need such fancy musical talents. For people who look for evolutionary explanations, of course, these animal songs are very puzzling. To us, however, the situation makes sense. The musicality of song birds and humpback whales makes nature more interesting. These talents were conferred by God, the Creator. Even before we had underwater listening devices, whale songs existed, waiting to be discovered. There are so many details of nature, known only to the Creator, that we must surely feel not only inspired to study more, but also humble that we know so little.