In April 2012 composer Richard Blackford heard extracts from Bernie Krause’s book The Great Animal Orchestra read on BBC Radio 4 Book Of The Week. By inventing the term ‘biophony’, or the collective voices generated by all the organisms in a given natural habitat and time, Krause invites the listener to become aware of the intricate layers of sound created by the animal world within natural habitats which he likens to the layers and textures of an orchestra.

When he first visited Krause in Northern California Blackford not only heard the beautiful recordings that Krause had created over 45 years in the field, ranging from Borneo and Zimbabwe, to the Amazon and many other countries, but he also saw their beautiful and compelling organisation on a spectogram, a graphic illustration of sound. Here was a visual impression of the extreme highest ‘instruments’ of the animal orchestra (the bats that are beyond our range of hearing yet visible on the spectogram) to the lowest growls of African elephants. Spectograms also illustrate the varied shapes of animal vocalisations – a swooping glissando, a hard, percussive pattern, a complex, skipping or melodious birdsong – remarkably similar to the notation and design of a musical score.

Krause pointed out the acoustic order (biophony) these collective animal voices generate; that instantaneous and organised expression of insects, reptiles, amphibians, birds and mammals in which they inhabit their own set time and frequency niches just as musical instruments operate within a given range in an orchestra. They even interact with each other, interrupting and resuming in the way a concerto soloist interacts with the orchestra. This then is Bernie Krause’s aptly named Great Animal Orchestra in which his unaltered wild soundscape recordings are combined with a full symphony orchestra.

Just as the acoustics of a concert hall or resonant cathedral have a direct bearing on how the music was conceived and is performed, so too are the animal sounds and songs shaped in large part by their habitats and acoustic environments. The rich resonance of a Sumatran tropical rainforest allows the white-handed gibbons to project their joyous duets with a thrilling reverberation, deliberately bouncing their calls off the geographic features of the landscape as well as the humid flora, leaves, branches and trunks of forest vegetation. By contrast, the dry, less reverberant acoustics of the desert works perfectly for the fox or coyote’s bark, whilst the nocturnal ambience of a tropical rainforest provides an ideal setting for polyphonic frog choruses. The composer’s first challenge was to create orchestral music whose character would change according to the ambient texture and context of the recordings that surround it.

Leos Janacek described “the melodic curves of speech” as a key element in his musical thought, and Blackford wondered how orchestral music might be created that derived its melodic curves and rhythms from Krause’s remarkable recordings.

So he set about sketching melodies and rhythms that could become the building blocks of his own orchestral music, layering multiple ostinati figures in the way the Balinese do in their Gamelan music, multiple tempi like Charles Ives, harmonising, making variations through augmentation and diminution, through intervallic variation and expansion and contraction of musical cells. Blackford wanted his orchestra to be a living organism, with the layers of melody and rhythm audible as a huge ensemble, like Krause’s wild soundscape recordings, or heard in their constituent parts, like a spotlight on a particular soloist.

To mimic or not to mimic? Animals in the wild – organisms, who vocalise in both competitive and cooperative relationships to one another – often mimic one another’s voices (like katydids, mocking birds, and certain whale species). And from the early stages of evolution we humans have mimicked the vocal and percussive performances of animals, from individual voices to entire organised structures. Examples include the Balinese ‘ketjak’ monkey dance, the instrumental and vocal performances of the Ba’Aka pygmy tribe of Africa, to the incorporation of birdsong into the orchestral works of Messiaen. In The Great Animal Orchestra Blackford decided to only mimic the astonishing Musician Wren in the fifth movement. Having notated it as a 44-note song (after which the bird repeats the sequence exactly) he couldn’t resist using it as a basis for a set of variations.