Digital sound archives can (briefly) revive extinct birds

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When people think of extinct animals, they may picture taxidermies, skeletons, 19th-century illustrations, or perhaps grainy black-and-white photographs. Until very recently, these were our only means of meeting lost people.

However, advances in technology allow extinct species to be encountered in new ways. With just a few clicks, we can listen to their voices.

In September 2021, the US Fish & Wildlife Service recommended removing 23 apparently extinct species from the endangered species list. This group included 11 species of birds, as well as various aquatic creatures, a fruit bat, and a Hawaiian plant.

Of the birds listed as possibly extinct, six were recorded while still present: Bachman’s warbler, ivory-billed woodpecker, and four species native to Hawaii and the Pacific Islands: bridled white-eye, Kauaʻi ʻōʻō, the great Kauaʻi thrush (kāmaʻo), and poʻouli. The technology capable of recording the sounds of birds was only developed about a century ago, so these are some of the first now extinct species whose songs have been preserved.

A not-so-silent spring

These recordings are available on the Cornell Laboratory of Ornithology’s Macaulay Library website, a massive multimedia wildlife archive that contains over one million audio recordings. It includes the sounds of 89% of all bird species on Earth in 2020, plus photos and videos. The site includes modern sound recordings uploaded by amateurs, professional sound recorders and scientists, as well as digitized historical recordings captured as early as 1929.

Scientists use these recordings to study questions such as the evolution of bird song and animal behavior. The recordings are also publicly available. Macaulay Library director Mike Webster told me that he views the recordings as time capsules: they allow us to hear what the world was like and preserve our current sounds for the future.

According to him, all the records in the library are precious. But the sounds emitted by lost species are akin to priceless works of art, like a Rembrandt or a Van Gogh – the very definition of irreplaceable.

Unfortunately, this new genre of extinct animal sounds is expected to grow. Birds have been hit hard by the current ecological crisis: in Canada and the United States alone, threats such as habitat loss, toxic pesticides and free-roaming domestic cats have reduced bird populations by nearly 3 billion since 1970.

Rachel Carson’s 1962 book “Silent Spring” inspired a generation of American environmentalists by arguing that if humans continued the destructive behaviors described by Carson, such as the widespread use of pesticides, the nation could face a source without birdsong. Sound recordings of missing birds add a twist to this prediction by allowing us to hear what has been lost.

To see the value of these recordings, let’s listen to two species: the ivory-billed woodpecker and the Kauaʻi ʻōʻō.

The Lord God Bird

The ivory-billed woodpecker, or ivory-billed woodpecker for short, is an iconic woodpecker species known as the “Lord God Bird” or “Holy Grail Bird” due to its striking appearance and extreme rarity. It used to occur in the southeastern United States, with a subspecies in Cuba, but has dipped in and out of presumed extinction since the 1800s. The main causes of its decline are believed to be rapid deforestation on a large scale after the Civil War and widespread culling by museum collectors.

This species is the most controversial on the US Fish & Wildlife Service list. Some people believe that ivory beaks still exist in the forests of the southeastern United States. The last universally accepted sighting was in 1944, but many more have been reported since, including some by scientists at the Cornell Laboratory of Ornithology in the 2000s.

Sound recordings of ivory beaks were collected in Louisiana in 1935 by Cornell ornithologists, who embarked on a sound-recording expedition across the country to capture sounds and images of “endangered birds”. disappearance” before their disappearance. There have been several other claimed sound recordings of ivory beaks over the years, including one in 1968 and some in 2006, but only the 1935 series of recordings is universally accepted by birdwatchers and birdwatchers.

For those still looking for the ivory beak, the 1935 recording is an important tool, especially since it is freely available online. People train their ears on the recording before their searches, and some even use it for “playback” – a technique where the recording is played in potential habitats in the hope that surviving ivorybills will respond. Scientists have also compared contemporary sound recordings they believe to be ivory beaks with the 1935 recording to suggest the species is not yet extinct.

A haunting and one-sided duo

The Kauaʻi ʻōʻō (pronounced ‘kuh-wai-ee oh-oh’) is a small, dark-colored bird endemic to the Hawaiian island of Kauaʻi and known for its complex, flute-like “oh-oh” song. It is one of 11 Hawaiian and Pacific Islander species listed by the U.S. Fish & Wildlife Service.

Hawaii was particularly devastated by environmental loss as European and American colonizers destroyed delicate island habitats to plant sugar cane and other cash crops. Introduced predators, malaria-carrying mosquitoes, and Hurricane Iniki in 1992 also contributed to the birds’ disappearance.

Ornithologist Jim Jacobi made a famous 1986 recording of an individual Kauaʻi ʻōʻō male singing half a duet – with no response. We have no way of knowing if it was the very last bird, but it’s hard not to listen as if it was.

A remix of a Kauaʻi ʻōʻō song was uploaded to YouTube by Robert Davis in 2009, with added echo and what he described as “the shrill sounds of commercial exploitation”. This remix, which juxtaposes the haunting cries of the bird with the cause of its decline, has been viewed more than 1.5 million times.

In my doctorate. researching historic bird sound recordings, people frequently refer to their emotional connection to the song of this species. A scientist told me that he had trouble listening to the recording without crying. Another performs it in lectures to help students understand the emotional dimensions of bird loss.

Sounds of saving the world

Sound recordings give animals a voice. They help demonstrate their unique spirits and personalities. They remind us that these beings are invaluable, and that humans have a duty to preserve them. I hope listening to the voices of extinct birds will cause people to mourn those who are already lost and strive to make other species sing.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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