How a hugely popular smartphone app is reshaping the hobby and reach of birding

By Anders and Beverly Gyllenhaal

First of Two Parts

Staffers at the Cornell Lab of Ornithology were caught by surprise when they came to work one Monday morning to discover a wave of 60,000 people had downloaded their Merlin smartphone app over the weekend.

Merlin’s starting page, offering three ways to identify birds: Sound ID, Photo ID or a series of questions to narrow down the choices.

The lab hadn’t marketed Merlin much as it worked to sharpen the software that helps people instantly identify the birdsongs around them. The growth of the app was coming a little at a time, strictly from word of mouth. “We thought, ‘What’s going on here?’ “ said Ian Owens, the lab’s director.

It turned out a TikTok influencer had posted a glowing video that spread far and wide, Owens said: “When you get up in the morning,’’ she encouraged her followers in a post earlier this year, “go outside, turn on Merlin and listen to the world.’’

When the Cornell Lab introduced the app a decade ago, Merlin offered a quick way for people to identify birds by answering just a few questions in the app. That initial version was a basic bird guide, not much different than the many competitors seeking to unravel the tricky art of deciphering birdsongs — with little of the magic the name implied.

Since then, Merlin has undergone dramatic improvements thanks to machine learning and innovative tools added to the app that can identify birds three different ways. Especially since the addition of sound identification in 2021, Merlin has boomed: Users young and old, tech-savvy and not have downloaded more than 15 million copies and put its growth on a trajectory that continues to rise sharply.

Merlin project coordinator Alli Smith. Photo courtesy of the Cornell Lab.

Millions of people who once had to rely on their own eyes and ears to identify birds are now using Merlin to instantly tell them what they’re hearing. It can not only identify multiple birds at once, the app picks up the huge percentage of the species you can’t even see. Over time, Merlin’s coverage has been extended to nearly all the globe’s 10,000 species, and the impressive accuracy of Merlin’s finding has left competitors hopelessly behind.

“People really love opening up the Sound ID and just having it interpret the world around you,’’ said Alli Smith, Merlin project coordinator at the Lab. “Having Merlin with you, it’s like its holding your hand, guiding you is such an easy way to get started. And it’s a lot of fun — and a little bit magical.”

Ian Owens, director of the Cornell Lab of Ornithology. Photo by Anders Gyllenhaal

It’s not an overstatement to say that Merlin’s blend of firepower and simplicity is reshaping how a growing number of people go about their birding lives.

Important as binoculars

As we traveled the country over the past six months, talking about our book on bird conservation, people constantly launched into how Merlin is enhancing their experiences on the birding trail. For many, the app has become as important as binoculars; it’s always in their hands, automatically showing a list of nearby birds. Because photos and names of singing birds pop up on your phone screen in real time, it teaches users to recognize songs, chips and calls.

People tell us they start their days over coffee with the app, dissecting the morning chorus all at once. Veteran birders with elevated birdsong skills talk about using the app to double check their own guesswork. Mike Parr, head of the American Bird Conservancy, a consummate birder who travels the world on behalf of birds, told us he likes to race Merlin to ID songs – and often loses.

The smartphone app is also helping extend the birding pastime beyond its traditional audience of mostly older people, many approaching retirement. “We’re seeing a big increase in mentions of Merlin on various social media platforms, many featuring people who are new to birding and are diverse across many categories including age, geography and race,” said Drew Weber, the Merlin project manager who led the creation of the app.

What’s that bird?

This first of two posts explores the growth and evolution of the Merlin app. The second post, coming in a few weeks, will look at how the app has mastered its identification alchemy and how the lab hopes to shape the app for the future.

Drew Weber, Merlin project manager. Photo courtesy of Cornell Lab.

The lab put together a string of TikTok posts, as an example, that shows teenagers boasting about how the app opens up a hobby that’s always been tough to navigate. That list included the influential poster, who ignited the mass weekend download.

“One morning she posts this video,’’ Owens said, “lying back in her chair on her deck and she has Merlin up. She says, “When you wake up, don’t look at Twitter or Facebook that are going to mess up your mind. Listen to what the birds are doing. You’ll feel mentally much better, just chilling out.’ ’’

We’ve heard stories about people sharing Merlin with friends, spouses and parents who find the app a way to get into birding without the years of practice it can take to master birdsongs by ear.

When Smith travels to birding events and runs the Cornell Lab’s booth, she hears no end of tales about how Merlin is helping create new birders. “People come up and say, ‘’I’ve been birding my whole life and I’ve never been able to get my kids or my family or my partner out birding with me,’ ‘’ she said. “But suddenly they have Merlin and now they’re going with me. Now they’re like, they’re running over, all excited, that they saw a finch on Merlin. That’s so cool.’’

Names and photos of species pop up as the Sound ID picks up their songs and calls.

Taking the guesswork out

Over the decade of its development, the Merlin app has gradually taken more and more of the guesswork out of bird identification. In that earliest form, Merlin worked strictly by asking people a series of five questions – from a bird’s colors to its actions – to narrow down the possibilities. Even then, most of the calculations were left up to the user.

Behind the scenes, though, the mechanics of birdsong identification that Cornell has championed for scientific research was lurching forward. At the same time as recording technology improved, the precision in machine learning has sharpened the ability to translate snippets of sound into the identification of species. (Watch for an upcoming post on how this works.)

Cornell staffers added the first version of its sound ID to a separate app called BirdNET Sound ID in 2018, and then in the spring of 2021 created the far simpler and intuitive version that’s now incorporated in Merlin. As soon as people began discovering the power and accuracy of Merlin’s sound identifications, reliance on the sound identification  – by far the element most people use – began to jump. Here’s a graph that shows Merlin’s growth by monthly users over the past several years:

Traffic on Merlin Steadily rising

Chart courtesy of the Cornell Lab of Ornithology
A sample page of the redesigned Merlin app that’s undergoing testing and should be released shortly.

While the evolution of Merlin has unfolded within the app’s original format, that is about to change. The staff is finishing up work on a redesign of the Merlin smartphone app that will give it a cleaner, simpler look to go with its other changes. The new version is scheduled for release before the end of 2023.

“Once a birder, always a birder”

A number of factors have combined to fuel this growth of Merlin as well as other citizen science tools. The pandemic ignited a birding boom as people discovered the birds outside their windows. Millions of new birders – so many that supplies of bird seed ran out for a time  – got their start during the months stuck near home.

Part of what’s driven this are the tools, not just the Merlin Bird ID, but Cornell’s companion eBird system that enables users to record bird sightings in a system that compiles that data to help guide conservation research.

As the pandemic eased, the lab’s staff has been surprised and delighted to see that Merlin’s traffic has continued to rise. The findings confirmed a trend that is encouraging both for birders and for birds.

“It’s telling us that once you become a birder,’’ said Smith, “you’re always a birder.’’

Now, thanks to Merlin, it’s a whole lot easier to get there.

What’s next: Watch for the second post in this series in a few weeks, looking at how Merlin works and where the Cornell Lab hopes to take this project as it tries to extend the app from mostly North American and European to the rest of the world.


OUR NEW BOOK: “A Wing and a Prayer”

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A riveting journey through the research breakthroughs, risky experiments and promising campaigns to save birds across the hemisphere, the book is praised from The New York Times’ book review to Good Morning America.


One response to “How a hugely popular smartphone app is reshaping the hobby and reach of birding”

  1. Merlin has helped me regain my interest and enthusiasm for birding. At 70 years old, my eyes aren’t quite so sharp, and worse, my ears have lost most of their higher frequency hearing ability.
    During the summer, while out splitting wood in my driveway, Merlin was compiling a list of the birds it was hearing. I had my doubts when it said there was a common yellowthroat out across the meadow. The habitat was right, and the yellow throat kept popping up on the Merlin list, so I made a focused attempt to adjust my hearing aids and cup my ears in that direction, and sure enough, there was the yellowthroat’s distinctive “witchity witchety witchity wit“ call, barely audible to my aged ears.
    Many times now I have been surprised by Merlin’s acute ears and quick ID skills, identifying the invisible vireos for me, and teaching me how common the blue grosbeaks really are in the summer in this part of the world. Never knew!

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