THE BRITISH LIBRARY

Sound and vision blog

134 posts categorized "Wildlife sounds"

19 September 2018

Seeing sound: What is a spectrogram?

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Greg Green, Audio Project Cataloguer for Unlocking our Sound Heritage writes:

In this digital age, most of us are familiar with audio waveforms, the ‘wavy’ images that represent the dynamic course of a particular sound recording. Waveforms are in fact a type of graph, with time on the X axis and amplitude (or loudness) on the Y.

Waveform exampleFigure 1: a waveform represents a sound recording by showing amplitude over time

Waveforms are very useful for conveying basic information about a recording e.g. where the loud bits are, where the quiet bits are, and how dynamic the recording is. If you were listening to an interview, a waveform can clearly show you where someone is speaking. Unfortunately, waveforms cannot tell us much about the pitch, frequency, or harmonic content of a recording. For that we can use a different visual representation of sound… say hello to the spectrogram!

How to read a spectrogram

Spectrograms keep time on the X axis but place frequency on the Y axis. Amplitude is also represented as a sort of heat map or scale of colour saturation. Spectrograms were originally produced as black and white diagrams on paper by a device called a sound spectrograph, whereas nowadays they are created by software and can be any range of colours imaginable!

Wave form v spectragramFigure 2: waveform and spectrogram of the same recording. An oscillating low frequency buzz dominates the waveform, only the spectrogram reveals where the bird is calling

Spectrograms map out sound in a similar way to a musical score, only mapping frequency rather than musical notes. Seeing frequency energy distributed over time in this way allows us to clearly distinguish each of the sound elements in a recording, and their harmonic structure. This is especially useful in acoustic studies when analysing sounds such as bird song and musical instruments. So not only do these graphs look really cool, but they can tell us a lot about the sound without even listening.

Spectrogram example (whooper swan)Figure 3: a spectrogram showing the harmonically rich calls of whooper swans

Whooper Swan calls recorded by John Corbett (BL shelfmark WS1734 C5)

In the above example, we can see the calls of a Whooper Swan represented in a spectrogram. The fundamental frequency of the calls is at about 750Hz, which is the frequency with the most energy (usually the lowest frequency of a sound), and gives the sound its perceived pitch. Above that are the harmonics - additional, quieter frequencies that give the sound its ‘colour’ and make up a sort of sonic signature – a Whooper Swan singing a perfect ‘G’ note will have a very different harmonic structure to a piano playing that same note. This information could be used to analyse bird songs and calls in different locations, or to understand the vocabulary of a species.

Creative uses for spectrograms

Clearly spectrograms can tell us a lot about the acoustic elements of a sound, but they are not just used for scientific studies. Audio editing is most often performed with waveforms as it's easier to make cuts or process a selected time range. When editing software uses spectrograms however, it opens up a whole new realm of possibilities! With this spectral editing, we are able to look into the microscopic details of a sound and apply processes to very specific time and frequency ranges. For example, an obtrusive footstep, or car alarm could be identified and removed from a recording, just like ‘photoshopping’ sound!

Spectral repair exampleFigure 4: a recording of a robin singing was ruined by a dog barking and some low end noise – a spectrogram reveals the unwanted noises and allows the recordist to remove them.

Spectral repair BEFORE

Spectral repair AFTER

Musicians can also use spectral editing to compose and generate sounds that could not be made any other way. Patterns and shapes can be ‘drawn’ into spectrograms and played back as frequency content. In some cases, detailed graphic images can be hidden within spectrograms. Aphex Twin used this technique to hide an image of a face within the second track of his ‘Windowlicker’ EP (1999).

Aphex Face

You can find some more examples of images hidden in the spectral content of popular songs here: https://twistedsifter.com/2013/01/hidden-images-embedded-into-songs-spectrographs/

So now you know what spectrograms are, how to read them, and some of their many scientific, creative, and bizarre uses. Keep an eye out for our #SpectrogramSunday @BLSoundHeritage tweets, starting this weekend!

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13 September 2018

Listening to mammals with the Batek

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Coleridge Research Fellow Dr Alice Rudge writes:

The Batek are hunting and gathering people who dwell in the lowland rainforests of Peninsular Malaysia. During my fieldwork with them, I played  some recordings of mammal sounds which are held at the Library. Batek people have extremely detailed ecological knowledge of the rainforest, and this is reflected in their in-depth understanding of its soundscape. I therefore played them these recordings with the idea that hearing these sounds might inspire people to give additional vocabulary or information about these sounds, based on their extensive knowledge.

You can listen to the recordings below:

Siamang duet recorded on Sumatra by Ashley Banwell (BL ref 62323)

White-handed Gibbon calls recorded in Malaysia by Reg Kersley (BL ref 06512)

Clouded Leopard calls recorded in Thailand by John Moore (BL ref 128288)

Binturong calls recorded in Thailand by John Moore (BL ref 61103)

Not only were people aware of what the animals were doing in the recordings I played, but they also accompanied this with cultural information, as well as talking about the emotions that hearing the sounds evoked.

For example, people said that the siamang and white-handed gibbon in the recordings are all running away from predators. In addition, they pointed out that in the siamang recording, the low sounds are the males, but the higher sounds are the females. 

In response to the siamang and white-handed gibbon in particular, people also exclaimed that they felt haʔip ­- an intense feeling of longing, yearning, love, or desire, which is often felt in response to things that are considered beautiful.

Photo credit: cuatrok77 on Visual hunt /  CC BY-SA
Siamang; Symphalangus syndactylus


The beauty of these mammal sounds is reflected in people’s musical instrument playing. The siamang is a favourite sound to recreate on the mouth harp, and the white-handed gibbon is a favourite sound to recreate on the flute. 

However, as well as feeling haʔip,  the white-handed gibbon recording also prompted people to tell the story of the gibbon, including the gruesome part at the end where evil cannibals cook and eat their mother-in-law, which resulted in everyone falling about laughing.

manfredrichter at Pixabay
White-handed gibbon; Hylobates lar

People recognised the sound of the clouded leopard as the yah bintaŋ - yah means ‘tiger’ in Batek, and bintaŋ (or bintang) is the Malay word for ‘stars’, referring to the pattern of its fur.

Photo credit: bobdole369 on Visualhunt /  CC BY-NC-SA
Clouded leopard; Neofelis nebulosa

In the binturong recording, they said that the female binturong is ‘trying to attract male binturongs to mate with’ (ʔoʔ ʔajak tmkal ʔom cycəy).

Photo credit: <a href="https://visualhunt.com/author/e39fc3">jinterwas</a> on <a href="https://visualhunt.com/re/f48d28">Visualhunt</a> / <a href="https://creativecommons.org/licenses/by/2.0/"> CC BY</a>
Binturong; Arctictis binturong

As is also the case for recordings of birds, using wildlife recordings of mammals in the field can therefore be useful for anthropologists, ethnomusicologists, or others who may be interested to find out more about how these sounds are experienced!

The Alice Rudge Collection of Batek recordings is currently being deposited and catalogued, and will be held under the shelfmark C1773.

29 August 2018

In amongst the wildebeest

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Cheryl Tipp, Curator of Wildlife and Environmental Sounds, writes:

In Disney’s The Lion King, the young cub Simba finds himself in the midst of a terrifying wildebeest stampede. Though our little hero survives the ordeal, a stampeding herd of wildebeest is certainly a force to reckon with.

Every year during the great migration, over one and a half million wildebeest leave the calving grounds of the Serengeti for the lush grazing pastures of the Maasai Mara. This journey from Tanzania to Kenya spans over 1,800 miles and is part of an endless cycle of movement that sees wildebeest, along with other animals such as zebra and gazelle, constantly on the move in search of fresh food and water. Though relatively sedate at times, it doesn’t take much to send this huge mass of bodies into a frenzied panic. All it needs is a whiff of danger.

Wildebeests-805391_1920

In 1988, French field recordist Claude Chappuis recorded a herd of stampeding Blue Wildebeest (Connochaetes taurinus) in the Maasai Mara. The accompanying recording notes make no mention of what caused the herd to take to their heels. Were they spooked by the presence of the recordist? Had a pride of lions or a solitary leopard been spotted nearby? And where was the recordist positioned while all of this was taking place? Was he in a nearby vehicle? Or on the ground? We assume that Chappuis and his equipment were safely out of harm's way, but with no contextual information to refer to, all we can rely on is our imagination. So sit back, close your eyes and picture the scene.

Stampeding Blue Wildebeest recorded by Claude Chappuis (W1CDR0000816 BD25)

This recording, along with tens of thousands of other wildlife examples, will soon be digitally preserved as part of the library’s Unlocking our Sound Heritage project.

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17 August 2018

Recording wildlife in the dark

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Cheryl Tipp, Curator of Wildlife and Environmental Sounds, writes:

There are plenty of positives when it comes to digitising archival sound recordings. Long term preservation and improved access are top of the list, however the opportunity to easily explore thousands of freshly digitised files is a curator’s dream.

The library’s Unlocking our Sound Heritage project has digitised an impressive 18,000 wildlife recordings over the past 12 months and this has brought a range of interesting content to the surface. One of our recent favourites is a nocturnal recording of Golden Plovers in the highlands of Scotland. The recording is wonderfully atmospheric, with Red Grouse and Snipe adding to the moorland soundscape. Yet this isn't the only thing that caught our attention. The accompanying metadata, provided by the recordists Charles and Heather Myers, demonstrates the difficulties of recording wildlife in the dark, especially when you encounter unexplained sounds.

Though our Golden Plover recording is dominated by bird calls, it also contains the grazing sounds of an unidentified animal. Charles & Heather were both accomplished naturalists and could identify the songs and calls of British wildlife with ease. Non-vocal sounds however, such as movement or eating, could leave even the most talented individual stumped.

You may be thinking "But couldn't the recordists just take a peek in the direction of the sound?" The answer is, not easily. The recording was made on remote moorland in the dead of night. In addition, the microphones had been placed over 45 m away from the camper van where their recorder was being operated. The only thing left to the Myers' was the power of deduction, as can be seen in the following recording note:

"As I was unsighted it is all guess work. But one thing is certain: the birds were very close. There were Red Deer about so I assume the grazing sound was made by one of these (was it a swishing tail that caused the bump on the mics?) You can hear him stop grazing & trot away to the right (3 min. 13)" 

Golden Plovers with possible Red Deer grazing nearby, recorded on 28th April 1989 in the Scottish Highlands (BL ref 20173)

3281339831_76a8ca1a36_b Could a hungry Red Deer be the source of our unexplained grazing sound?

We'll never know whether the Myers' did record a Red Deer grazing on the moorland turf. Unidentified sounds are often part and parcel of the field recording process, so it's down to the recordist (or the curator!) to fill in the blanks. But, at the end of the day, that's all part of the fun.
 

Follow @CherylTipp for all the latest wildlife news.

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20 July 2018

Mrs Boulton and the woodland warbler

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Have you ever noticed how some animals are named after people? Hume's Partridge. Lady Amherst's Pheasant. Waller's Starling. I come across this quite a lot when cataloguing new collections and have often wondered who these people were.

You'd be forgiven for thinking that these species were named after the naturalists who discovered them. Now, there are no rules that say you can't name a new species after yourself, however it's generally regarded as bad form in most taxonomic circles. Helps keep the egos in check etc.  It's perfectly acceptable to name a species after somebody else though. Most names are given as a declaration of admiration or love, however a few have been chosen out of spite. What better way to insult a critic or a rival than by naming a disagreeable specimen after them? Carl Linnaeus, the father of modern taxonomy, was the king of the nomenclature slap down. Mess with Linnaeus and you could be sure that a smelly weed or a boring nettle would soon bear your name.

In this particular example we're going to look at Mrs Boulton's Woodland Warbler, Seicercus laurae. Now more commonly referred to as Laura's Woodland Warbler, this little songbird can be found in the dry forests and swamps of central Africa. The species was discovered in 1931 by the American ornithologist W. Rudyerd Boulton (1901-1983) who specialised in the avifauna of Africa. While assistant curator of birds at the Carnegie Museum of Natural History, Boulton made several research trips to Africa accompanied by his first wife, the ethnomusicologist Laura Crayton Boulton (1899-1980). It was with Laura that he discovered this previously unknown warbler which he named in her honour.

Laura's Woodland Warbler, recorded at Mount Namba, Angola by Michael Mills (BL ref 163291) 

The Boultons continued to explore the ornithological and musical treasures of Africa until the mid 1930s when their marriage began to fall apart. The couple finally divorced in 1938 and, though Laura continued in the field of ethnomusicology, Rudyerd's professional life took an entirely different turn. In 1942 he joined the African branch of the Office of Strategic Services (OSS), the US intelligence agency formed during World War Two, where his knowledge of the landscape, people and politics of central African countries was put to good use. In the same year he married his second wife, the socialite, poet and psychic Inez Cunningham Stark. Though mainly based out of Washington DC, Boulton was heavily involved with operations in the Democratic Republic of the Congo, most notably the procurement of uranium ore for the Manhattan Project.

At the end of WWII, Boulton continued working in intelligence for several years, including a stint with the CIA, until, apparently at least, turning his back on espionage in 1958. A year later he created the charitable Atlantica Foundation with his third wife, the wealthy widow Louise Rehm. The remit of this foundation was broad but ambitious, aiming to establish and support research into zoology, ecology, fine arts and parapsychology. The couple based their operation out of Zimbabwe and were by all accounts generous supporters of research and education in the area until their deaths in 1974 (Louise) and 1983 (Rudyerd).

But what of the woman who inspired the name of our woodland warbler? Laura Boulton became a renowned field recordist, filmmaker and collector of traditional musical instruments from around the world. During her life she embarked on almost 30 recording expeditions throughout Africa, Europe, Asia and North America, amassing tens of thousands of sound recordings, photos, films, books and instruments. She experienced first hand advancements in recording technology, beginning her career with an Edison phonograph before progressing to a disc cutting machine and eventually a portable reel to reel recorder. Her legacy can be found in various institutions across the United States, from the Center for Ethnomusicology at Columbia University to the Archives of Traditional Music at Indiana University. 

Boulton LP  One of Boulton's published collections of ethnographic field recordings (BL Shelfmark 1LP0247765)

When beginning my research I never imagined that two such colourful characters would be behind the name of this rather inconspicuous little warbler. Two years after the discovery of Laura's Woodland Warbler, Rudyerd was himself taxonomically immortalised by the American herpetologist Karl Patterson Schmidt, who named a new species of Namib day gecko, Rhoptropus boultoni, in his honour. And in case you're wondering, Schmidt must have liked Rudyerd. Rhoptropus boultoni is a pretty cute gecko.

Follow @CherylTipp for all the latest wildlife news. 

09 July 2018

Recording of the week: exploding seed pods

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This week's selection comes from Cheryl Tipp, Curator of Wildlife and Environmental Sounds.

The soaring temperatures of summer can have explosive results, especially if you happen to be standing near a gorse bush. This thorny, evergreen shrub produces an unmistakable sea of bright, yellow flowers from January to June. As the flowers begin to fade, a mass of black seed pods emerge to take their place. Slowly but surely, the heat of the summer sun dries out these downy carriers until the structures burst open, expelling the tiny seeds enclosed within. The force of this explosion produces a sharp, popping sound, as can be heard in the following example recorded on the Isle of Wight by Richard Beard.

Exploding seed pods (BL ref 212269)

24921214482_051c505a74_bGorse seed pods (Photo credit: Starr Environmental on VisualHunt / CC BY)

This recording was chosen in memory of the field recordist Richard Beard (1953-2018) whose work in the wildlife section helped process hundreds of unpublished collections for more than a decade. Richard also contributed many thousands of his own recordings to the British Library, some of which can be heard in the Weather and Water collections on British Library Sounds. An oral history interview with Richard, conducted in 2013, can be found here.

Follow @CherylTipp and @soundarchive for all the latest news.

27 June 2018

Using wildlife sound recordings in the field

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Coleridge research fellow Dr Alice Rudge writes:

What are the uses of the recordings we make beyond preserving them? How might archiving wildlife recordings open up possibilities for interdisciplinary research, beyond the original purpose of the recording? During my anthropological PhD fieldwork with Batek people in Malaysia, which focused on their uses of music and sound, using wildlife sound recordings in the field created some interesting outcomes.

Batek people are indigenous hunter-gatherers of the lowland rainforests in peninsular Malaysia, numbering around 1,500 people. They speak Batek, an Austroasiatic language of the Northern Aslian family.

DSCF2768
Evening fishing and flower collecting

In a Batek camp, or when out in the forest, birds are a common topic of conversation, and under the dense canopy of the forest, birds are some of the most noticeable creatures, not because they are seen, but because they are heard (see also Lye 2005). All that might be seen is a flash of colour or a shaking leaf, but birds’ calls cut across the background hum of insects and chatter. Perhaps for this reason, birds are a major source of musical inspiration. Birds are cosmologically significant, too, and played an important role in creating the world as it is today, according to Batek origin stories (see also Endicott 1979). They are also used to make predictions - for example if you hear a certain bird you might know that certain fruits are ripe, that elephants are close, or that a friend will arrive home that day. Birds are often named onomatopoeically for their calls - for example the sŋseŋ bird has the call ‘seŋ-seŋ-seŋ-seŋ’.

This evident salience of bird sounds for Batek people meant that I was interested to document Batek names for various birds during my fieldwork - partly so that I could then ask further questions about them! However - when out in the forest, if we heard a bird and someone told me the name of it, it was difficult for me to then know the English name of it based on the sound alone. I therefore got hold of some of recordings of Malaysian birds, and, alongside showing them images from photographic field guides, played them to my Batek friends with the idea that they would be able to tell me the Batek names for the birds, which I could then compare to the English names noted by the original recordist. This proved a fascinating exercise - in particular as often there was not any one simple answer or direct correspondence between the English and Batek names for birds. For example, the aforementioned sŋseŋ was variously identified from the images as the Black-eared Shrike-babbler, Long-tailed Sibia, White-bellied Erponis, Oriental Reed-warbler, Arctic Warbler, Mountain Leaf-warbler, Chestnut-crowned Warbler, Blue-throated Flycatcher, Yellow-throated Flowerpecker, Crimson-breasted Flowerpecker, Orange-bellied Flowerpecker, and the Scarlet-backed Flowerpecker. However, from the recordings it was more definitively identified by different people as the Brown-throated Sunbird.

Furthermore, not only did people help me to document a lot of bird names, but they were also keen to recount stories and other information about the birds. For example, on listening to the Crested Jay, ʔEyJayat identified that it was a lhlah in Batek, but also recounted a funny story about coming across a tourist in the forest: the tourist was reaching up, trying to record the lhlah bird with their microphone - but this took ʔEyJayat, who was walking in the forest, by surprise as he thought the tourist was a ghost. ʔEyKtlət also remembered that the lhlah was the bird we had heard in the forest that morning when we had been fishing. He, his wife, and his son talked about how the lhlah has two sounds - syãl and llɛk. If you hear these sounds it means you won’t find food in the forest that day. If you are tired, and have no food, or only a tiny bit of food - you will hear it. If you get back home and your lean-to is damp - you will hear it. People therefore feel angry when they hear this bird! Through this exercise, Batek friends also taught me that the baləŋ bird indicates that elephants are close, as it makes the sound tuləŋ that imitates the sound of an elephant trumpeting, and that the maliʔ bird calls rain to come (ʔoʔ ʔajak ʔujan). The ləʔ talok bird (a type of Scimitar Babbler) - whose name literally translates as ‘indicates the Dusky Langur’ indicates that Dusky Langur are close!

The recording that people found the most hilarious was of the trut kit, or ‘fart’ bird - whose call sounds a lot like somebody breaking wind. Not only did I learn this funny name for the Mountain Imperial Pigeon - but also everyone fell about laughing about the bird, saying yɛʔ malɛs nir klɨŋ - ‘I really don’t like the sound’, imitating the sound, and then laughing again. In the Batek’s forest, however, laughter can be taboo (lawac), and risks causing a storm - and in the recordings people can be heard warning each other - ‘watch out or we will be lawac from laughing so much’. As well as giving information about birds, the new recordings of people listening to these recordings therefore also document something about Batek humour and taboos more broadly.

The jayit srwal bawac bird - which in English is the Chestnut-capped Laughingthrush - has a name which translates as ‘sewing the trousers of the macaque’. This bird also has other messages - as it is also heard as saying cok buŋah kwaʔ and jŋʔɨl tlok kawah - telling the listener to prepare the kwaʔ flower to be worn in the hair and to jump into the water at kawah - a part of the nearby river. These messages are ‘phonological iconisms’ of the birds call. In other words, the words sound like the sound of the bird. This bird is therefore particularly inspiring to and well loved by the Batek, it is strongly associated with a particular place and with flowers that the Batek love, and its call often therefore prompts exclamations of feelings of longing and nostalgia, which the Batek call haɁip. You can listen to the sound of the bird, followed by ʔEyKtlət repeating its name, in the audio excerpt below:

Jayit srwal bawac

Through recording Batek people listening to the recordings, therefore it has been possible to preserve some of this complex and in-depth knowledge and love of birds that Batek people have, knowledge which is deeply connected to their forest home, and their daily experiences of the birds. The exercise has showed that wildlife recordings can have great use beyond documentation - in this case by providing a resource for eliciting, sharing, and in turn preserving, further unique knowledge, and providing a window onto important ways of thinking about the environment that challenge dominant discourses, and show the ways that human and avian lives can intertwine.

The Alice Rudge Collection is currently being deposited and catalogued with the World and Traditional Music collection as part of Alice's ongoing research with the Batek.

For more information on Batek people, see the following:

Endicott, K.M., 1979. Batek Negrito Religion: The Worldview and Rituals of a Hunting and Gathering People of Peninsular Malaysia, Oxford: Clarendon Press.

Lye, T.P., 2005 [2004]. Changing Pathways: Forest Degradation and the Batek of Pahang, Malaysia, Petaling Jaya, Malaysia: Strategic Information Research Development.

Rudge, A., forthcoming 2018. The sounds of people and birds: music, memory, and longing among the Batek. Hunter Gatherer Research. 

 

11 June 2018

Recording of the week: a Mute Swan's heart

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This week's selection comes from Greg Green, Audio Project Cataloguer for Unlocking our Sound Heritage.

There are hundreds of thousands of recordings of birds in the sound archive, but not all are of the typical songs and calls we would expect. I have come across recordings of wingbeats (swans, pigeons, ravens and hummingbirds all make fantastic wing sounds), drumming/pecking (woodpeckers and nuthatches), and bill clattering (the somewhat bizarre display of albatrosses). However, there are a few special recordings of something truly intimate, a heartbeat!

Mute Swan heartbeat, recorded by Richard Ridgway on 8th December 1970 (BL ref 29109)

The Mute Swan’s heartbeat in this recording was captured by the late Richard Ridgway on Kilcolman Wildfowl Refuge in County Cork, Ireland. Richard owned and ran the refuge with his wife Margaret. This recording clearly captures Richard’s passion and care for the birds at Kilcolman as well as his interest in sound recording.

  Mute SwanMute Swan, taken from Coloured Figures of the Birds of the British Islands, 1885-1897 (CC-BY, Biodiversity Heritage Library)

Mute swans are normally very defensive and can be incredibly aggressive when threatened. So it is no mean feat that Ridgway managed to tame this bird enough to be able to place a microphone on its chest and stroke its head. He even notes that the swan's heart rate increases when it is stroked. The swan also calls in this recording, and almost seems to respond to the recordist’s voice, which sounds unusual when recorded straight from the birds chest. It’s hard not to smile when imagining a man cuddling a swan while listening to its heart!

This recording has been digitised as part of the library's Unlocking our Sound Heritage project.

Follow @gregegreen@BLSoundHeritage and @soundarchive for all the latest news.

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