“There are extraordinary parallels,” said American ornithologist Donald Kroodsma, author of “Birdsong for the Curious Naturalist: Your Guide to Listening.” “Culture, oral traditions – all the same.”

The first bird dialect expert

For centuries, bird song has inspired poets and musicians, but it wasn’t until the 1950s that scientists began to pay attention to bird dialects.

In the 60s and 70s, scientists put baby birds into a sound isolation room to see if they could sing their songs, according to bird expert David Luther.

The scientists found that some birds – who study their songs – could not sing at all. “They just continue like baby babble all their lives,” he said. The birds are known as “true singing birds”. In other birds, singing is innate. “When they grow up, they can only sing the perfect song without problems.”

When birds imitate adults, scientists find, they sometimes make mistakes. The error was then copied by another bird, and a local dialect flourished. That means that dialects can only exist in true singing birds because they have “learned oral traditions,” Kroodsma said.

Dialects can also be made when birds adapt to the local environment, says American ornithologist Elizabeth Derryberry. Birds that can be heard better can find a better partner, which means their song is more likely to be passed down from generation to generation.

This is related to the idea developed by Bernie Krause, founder of soundscape ecology, that animals make sounds in different tones so they can all be heard.

Some dialects change quickly – even in the breeding season. Other birds hold on to their dialect for decades. When Luther examined the San Francisco dialect of a white crowned sparrow – a common bird in North America – he discovered that some dialects have not changed at all in 40 years.

Dialect and dating (in birds)

For something that is often the result of copying errors, dialects can be very useful.

According to Molles, birds communicate for two reasons: Either they try to evict their neighbors, or they try to attract the attention of females. “Unfortunately, nothing is poetic,” he quipped.

When it comes to defending the territory of other birds of the same species that are not local to the area, knowing the local dialect allows for more complex interactions. Copying a song note is considered aggressive for birds, so having a wider repertoire means that birds can convey their intentions without increasing interaction into fighting.

Knowing the local dialect is also useful for finding a romantic partner.

In many species, the males sing. According to Molles, females tend to prefer a familiar dialect – this shows that male birds know the local area, own territory, and not just “someone who passes by it.” Some birds are bilingual, or even trilingual – maybe because they grow around different local dialects. When they mate, they will choose to sing local dialects wherever they choose to settle, Luther said.

But not having the right dialect is not an insurmountable barrier.

Kroodsma gives the example of a prairie commander in Massachusetts, where he lives, who has returned every year for the past few years. Although the bird has a very unusual song, it attracts females and raises babies every year.

“Someone might say, ‘Well, there’s a novelty effect, a man with a very different song and all women think it’s sexy,'” he said. “But that’s just a wild guess.”

This is something researchers think about in places like New Zealand, where threatened birds are sometimes reintroduced to new areas. The researchers want to ensure that if they reintroduce birds, they will reintegrate, even if they do not have the right dialect.

In Molles’ experience, it tends to function if a group of birds is reintroduced simultaneously, so they have a fellow bird with a strange dialect.

He was involved in reintroducing Kokako – a native blue-gray bird with a call like a violin – to the New Zealand area hundreds of kilometers away from where they were born. At first, newcomers might multiply among themselves, he said. But in the future, they might integrate. Descendants of newcomers will likely start interbreeding with descendants of native populations who grow familiar with both local and new dialects.

“The woman is not necessarily looking for someone who fits the song sung by her father,” Molles said. “He found a match that matched the area where he wanted to settle – he wasn’t just a strange bird that might not be his.”

How humans change bird dialects

When cities around the world are locked, a series of questions arise on Derryberry.

Over the years, birds began to sing in higher tones in cities to be heard because of low traffic and construction. What will happen to the birds when the city is quiet? If it’s calmer, will a new generation of birds sing in lower tones? And next year, when it comes time to breed, will they sound like city noise again?

He was still trying to answer these questions, but Kroodsma was skeptical that a brief period of silence could be long enough to have an impact on bird dialect.

Even if the death of our coronavirus hasn’t changed the bird dialect this time, it’s good to think about how we form – and destroy – the bird dialect in general. Something as small as an electric cable can suffice to break up bird populations and lead to the creation of new dialects, Kroodsma said.

Molles remembers finding historical records from the Kokako natives who are now gone.

“Some of the songs on the tape are amazing – strange metal sounds that you would never expect were made by birds,” he said.

“It’s sad to hear some of that and think, We will never hear it again.”