2017-09-07 / Nature

Birding by Ear is an Acquired Skill

By Charles Avenengo

Hearing, for birdwatchers, while subtler than the sense of sight, is equally important. Bird song is everywhere, and an experienced birdwatcher can stand virtually anywhere and distinguish the various bird songs without actually seeing the birds. These identifications are often made from great distances. When a bird song or call is out of the ordinary, it draws scrutiny and warrants investigation, often leading to the discovery of a rare or uncommon species.

While most birdwatchers in the field can identify bird songs delivered primarily during breeding season, call notes present a more challenging skill set. Uttered all year, a call note is generally a single note, often a “chirp,” and it represents a completely different part of a bird’s vocabulary.

A call note indicates many things. It could be an alarm in response to a nearby predator, aggression against a rival, or a way to maintain contact between other members of a flock. Skilled birdwatchers can rattle off the presence of birds not only by their song, but by their call notes, many of which are barely audible.

Highly skilled birdwatchers can also identify flight calls. Most flight calls occur during nocturnal bird migration, when birds fly overhead, and these vocalizations serve as notes used primarily to keep flocks together. Only a small percentage of birdwatchers have the ability to identify these flight calls, as the birds fly by swiftly at night.

In the tropics, field ornithologists, often faced with the inability to penetrate a dense jungle full of danger, are forced to stay on the trail. Sorting out the various calls by sound is crucial. Birds proliferate in the tropics, and every few years a bird species new to science is discovered.

Invariably, these species are initially identified by their calls or songs. A recording is made of the sounds and subsequently studied. Scientists then close in for the visual proofs, if it is indeed a new sound. Only a handful of birdwatchers are at this level of identifying tropical birds by ear alone.

In the U.S., an extreme sound challenge is put to the test at night. On a variation of the “Big Day,” an event conducted generally in spring, when birdwatchers attempt to see or hear as many bird species as possible in a single day, the “Big Night” has evolved in recent years. Because it is conducted after dusk and before dawn, it is naturally dark and birds are rarely seen, so identification by sound is the crucial element. A recent Big Night in Colorado yielded 47 species identified over the course of a single night.

Of course, practice helps. For this, there are aids. An industry has been created to help birding by ear. Most notable is the advent of digital audio devices, tapes and applications (apps) of bird songs and calls. Birdwatchers listen to these tapes and apps to practice sorting out the various notes they will hear once they are in the field.

These aids are also used to draw in shy birds. In a process called taping or “playback,” birdwatchers use tapes of a particular bird’s song or call to lure in the species. Upon hearing the taped call, the bird will aggressively emerge to investigate the potential rival intruding into its territory. While highly effective, the use of playback can be considered unethical, and there is a debate surrounding the use of the recorded bird song. At some wildlife reserves, including the Norman Bird Sanctuary, playback is not allowed.

Finally, for the hard of hearing or for beginners, technology is helping. Bird song recognition algorithm apps have been in development for over a decade and are just beginning to hit the market. Similar to the Shazam app, which enables users to point their devices at music to identify a song, the bird song recognition apps pick up bird songs and calls in the wild, identifying the vocalizing bird.

Without sound identification, it would still be a “jungle” out there for birdwatchers.

Naturalist Charles Avenengo has been chasing Aquidneck Island wildlife for more than 40 years.

Return to top