In the past few years, the study of birdsong has witnessed an incredible explosion of interest by both scientists and birders. For scientists, being able to identify species automatically by call with the aid of remote microphones and computers has become a holy grail for expanding human understanding of bird populations, behavior, and conservation. For non-scientists, well, learning and identifying bird sounds marks nothing less than the Great Divide between proficiency and expertise.
For me and many others, the ability to identify birdsong carries an added significance. Shortly after I began birding about six years ago, my hearing took a swift, dramatic plunge, and I lost many of the higher frequencies utilized by songbirds. For a while, as I focused on identifying birds by sight, this loss proved mostly an annoyance. As my visual skills increased, however, I realized with dismay that my hearing handicap threatened to limit my ability to pursue my favorite activity permanently.
In a previous article, I reviewed field guide and listing apps, while here I look at apps that help birders learn and identify birdsongs. When I began evaluating field identification apps for this review, I was not only curious about what they could do. I asked myself, “Could any of them remove a key barrier to my own growth as a birder?”
For now, at least, the answer is no — and for two reasons. One is that birdsongs (by which I also include calls) are incredibly complex. Not only are they structurally intricate, but they also exhibit mind-boggling variation both within species and individuals. Lazuli Buntings, for instance, employ at least 140 different “syllables” in their songs, and no two birds put these together in the same way. Red-eyed Vireos can potentially create thousands of different songs, though any one bird mercifully uses only a slice of its potential repertoire. Training a computer program to identify this almost endless variety of sound correctly, it turns out, is a monumental challenge — especially for an app sitting on your phone.
And this brings me to the second reason field identification apps are not going to revolutionize your birding any time soon: Even the most advanced algorithms are no match for the human brain. This was impressively demonstrated to me recently when I went out birding with my 17-year-old son, who was doing point counts around our neighborhood as part of a senior-year science project. At each location, he had to perform myriad complex tasks, including filtering out background noises, isolating one bird call from numerous others, comparing calls with his own internal library of information, and, yes, correctly identifying the birds making each sound.
Any of the operations could easily become a life’s work for the most talented computer programmer, and yet my son — and legions of other birders — perform these tasks almost simultaneously. Watching him work gave me a supreme appreciation for the human brain and sensory systems — and the enormity of the challenge facing developers and scientists.
The good news? People are working on it! Will you be able to walk out into the woods on a May morning, activate an app, and get a list of the dozen species of birds singing around you? Not even close. Will you be able to approach a loud, relatively isolated bird and get a solid idea what it is from its call? Under good conditions, probably.
But that’s not all that apps can do for you. Apps in this review provide libraries of songs that will help you narrow down what you’re hearing by location and probability. Even more fun, some can help you train your “mainframe” brain to recognize birdsongs for itself.
With these things in mind, I have focused my review on two groups of apps: those that attempt to automatically identify a birdsong in the field or from a recording, and apps that help you strengthen your skills, especially through quizzing and repetition.
Group 1: Birdsong Recording Identification Apps
I compared five different apps designed to automatically identify a birdsong either live or from a recording: Song Sleuth, ChirpOMatic USA, Bird Song Id USA, BirdGenie, and Smart Bird ID. It was quickly evident that all face similar challenges. Simpler songs such as an American Robin or the two-note call of a Black-capped Chickadee often, but not always, scored a correct hit, or at least got included in a short list of choices.
However, all of the programs struggled with more complicated calls and would usually punt to incorrect options. When I tried the call of a Savannah Sparrow, for instance, Song Sleuth, ChirpOMatic, and Bird Song Id all came up with sparrows, just not the correct ones. This is still fairly impressive and would get a beginning birder into the right ballpark. (I could not find Savannah Sparrow in BirdGenie’s song library, but the app correctly identified Song and Chipping Sparrows.) But — and this is a big but — all of the above tests were under “laboratory conditions” in my office, playing Cornell Lab of Ornithology recordings right next to my phone. How did these same programs do in the field?
It depended on conditions. When I could get close to a bird that was not swamped by other noises, an app had a fair chance of choosing the correct species — sometimes to my great surprise. However, all of the apps frequently missed, often by a wide margin. That said, the song recognition systems for at least one of these apps is constantly being improved, and if birdsongs interest you, I especially recommend the following for their relative accuracy, educational value, and ease of use.
Your Best Shot: Song Sleuth
Developed by Wildlife Acoustics in collaboration with David Sibley, Song Sleuth is far and away my favorite app for identifying bird calls in the field. On a hike last summer, I was bombarded by Lazuli Bunting calls, no two of which were alike. I recorded one for the app and was astonished that it listed the species as one of the three choices. For other calls, it also correctly came up with Western Meadowlark and Western Wood-Pewee as top-three possibilities. “Not bad,” I thought — again with the caveat that I was pretty close to all three birds and not a lot of other confusing calls or background noises were nearby.
What makes Song Sleuth so great, though, is the way it allows you to listen to and record birds. Once you’ve opened up the app, it scrolls a continuous spectrogram of all of the sounds around you. When you hear your desired bird, you hit the record button and stop it when it’s over. The app automatically draws a box around the call it thinks you want, including — and this is the cool part — the portion that started playing before you hit the record button. If the box doesn’t corral what you want, you can move it and change its shape on the spectrogram. Then, you hit a button to ID the call.
It’s hard to describe how elegant this system is, but the main point is that it doesn’t make you guess when you’re going to hear your bird and waste a lot of time trying to record songs that don’t materialize. A huge bonus is that you get to learn what a call looks like on the spectrogram. My brain contains too much cement to memorize different spectrograms, but I find it fascinating to visually compare what I’m hearing with the frequencies and shape of the calls around me. (Note: BirdGenie uses a similar continuous recording approach to capturing songs and also shows you the spectrogram, but only after you stop recording.)
Unfortunately, while writing this review, I learned that Wildlife Acoustics is no longer upgrading and supporting Song Sleuth. I do hope the company reconsiders its decision, but if this cool app sounds interesting, download it while you still can.
In my tests, ChirpOMatic scored about as well as Song Sleuth when it came to identifying calls. I did not care for the recording method, since it makes you guess when your bird is going to sing, but even with this drawback, the app remains quite functional and enjoyable to use. Like Song Sleuth and the other apps I tested, ChirpOMatic comes with a nice built-in library of bird calls for quick and easy reference in the field. Both it and Song Sleuth save your recent recordings, including those that they correctly identify. ChirpOMatic also allows you to submit these so that developers can keep updating the app’s accuracy.
Making Waves: BirdNET
I’d be remiss if I didn’t mention an especially exciting song-identifying program recently released from Cornell Labs and Chemnitz University of Technology: BirdNET. BirdNET actually may end up doing what I earlier said was impossible — identifying multiple bird calls at the same time. When I began writing this article, a prototype of the app was available only for Android devices, but developers recently unveiled an IOS version, so I was able to test both. As with Song Sleuth, you launch your session by hitting a record button, and a spectogram begins rolling across the screen. After you stop it, you select the area of the spectogram that interests you and wait for the analysis.
How did BirdNET do? Well, last fall I used my son’s Android phone to try to capture and identify robin sounds, and it came up with Pine Siskins. “Hm,” I thought, “that’s strange.” Then I looked up to see six siskins sitting in a tree! Over the next hour, BirdNET correctly picked out European Starlings, Cedar Waxwings, Red-breasted Nuthatches, and Black-capped Chickadees — and not under particularly easy conditions. The IOS version seems similarly accurate, and in addition to birds I was expecting, the app drew my attention to surprise Violet-green Swallows and Song Sparrows. As you’d expect, the program’s success depends on environmental conditions, but it does a good job filtering out non-bird noises and seems to be able to handle at least two species singing at a time.
After you stop recording, the app sends what you hear along with metadata — location and date information — to computers in Germany for analysis and then shoots back the results in a matter of seconds. BirdNET uses a “deep artificial neural network” (artificial intelligence) to make bird IDs and even ranks its results from “Highly Uncertain” to “Highly Certain.” The downside is that you need an Internet connection to see your results in the field.
Fortunately, BirdNET developers have even bigger plans for the app. In the next couple of years, they plan to make it self-contained so that it doesn’t require an Internet connection. They also plan to increase the number of bird species. Currently, it can identify about 1,000 species from North America and Europe, but the developers plan to expand this to a mind-blowing 6,000 or more, making it useful on every continent.
Finally — and perhaps most impressively — they hope to add a real-time mode that continuously IDs species as the spectrogram of vocalizations rolls by. Even if they don’t succeed in accomplishing all of this, the current app leaves little doubt that BirdNET will soon become the go-to birdsong ID app for birders across the globe. Don’t believe me? Watch the BirdNET demo on birdnet.cornell.edu, or better yet, download the app for yourself.
Oh, and did I mention that it’s free?
Merlin: A terrific teaching tool
In the summer of 2021, the Cornell Lab of Ornithology unveiled a new song identification feature for its excellent Merlin Bird ID app. Like BirdNET, Merlin’s “Sound ID” feature was developed with AI technology, using known spectrograms to teach it to identify more than 400 North American species. Once you start Sound ID, a continuous spectrogram scrolls across the screen, and when a bird is identified, the species name pops up below, accompanied by a photo.
Especially for someone with a hearing disability or who just doesn’t know birdsong, it can be like magic watching a succession of bird names appear before your eyes. No doubt it will make a terrific teaching tool, especially for those just getting into birding.
The program is not without its limitations. Unlike BirdNET, Merlin’s Sound ID is a stand-alone feature, which gives it the flexibility to work without cell service, but it may also limit its accuracy. In quick tests around my largely forested neighborhood, Sound ID correctly picked out most species but mistook some common birds for unlikely rarities, such as American Three-toed Woodpecker and Northern Pygmy-Owl. Still, the app constitutes a major step forward in birding technology, and Cornell will undoubtedly continue to improve it over time. For now, though, birders will probably want to use Sound ID more as a learning tool and continue to hone and rely on other skills to confirm their own bird observations.
Group 2: Apps for learning and quizzing
As the above discussion implies, there is no substitute for having a working knowledge of bird calls while you’re out in the field. Even if an app can narrow down a call to a top three or five possible birds, you still must have a good idea of what you’re listening to. Enter bird quiz apps.
Bird quizzes are the fun way to sharpen your field ID skills and stay “bird active” no matter where you happen to be. In writing this review, I tested a variety of birdsong quizzing apps and found that Larkwire and Chirp! Bird Songs & Calls USA soared to the top of my list.
Great for beginners: CHIRP! Bird Songs & Calls USA
Especially if you are new to learning birdsongs, I recommend Chirp! Bird Songs & Calls USA because of how easy it is to dive in. The app offers you three levels of difficulty that are fun for both beginning and intermediate “ear birders.” For each, it shows photos of the possible choices, and you just tap the one you think is correct. What I found especially useful is that the app allows you to build your own quizzes from a library of more than 250 North American bird calls. Wrens, for instance, constantly befuddle me, and Chirp! USA allowed me to build a quiz of House, Bewick’s, Pacific, and Marsh Wrens. (And, no, I haven’t yet mastered them, thank you for asking.)
When you’re serious: Larkwire
Like Chirp! USA, Larkwire offers quizzes for birders of all skill levels, but it advances birdsong education to a whole new level. It’s fair to say, in fact, that Larkwire is as much of a master class in birdsong as it is a quiz.
At the beginning level of the Western North America Landbird Songs module, for example, it takes you through six groups of songs organized by type, each with several relatively common species in it. These groups include such things as Clear-toned Songs, Simple Songs, and Rattles & Trills, and you have the option of seeing photos of possible birds or identifying them blindly. The difficulty of the different groups immediately intrigued me as I cruised through Clear-toned Songs — but had to dig a lot deeper to untangle Complex Songs and Rattles & Trills. Don’t even ask how I did at the intermediate level, where I was confronted by 26 different groups! Advanced and master levels contain even more groups and a greater variety of calls. As B.B. King so concisely put it, “Someday, Ba-bee …”
Like Chirp! USA, Larkwire allows you to construct your own tailor-made bird quizzes, and while testing it, I had the opportunity to ask developer Phil Mitchell what compelled him to come up with this fun, challenging app. “I’m a very lazy birder,” he confided. “I love birding but have never been very good at studying things on my own. I bought all the birdsong CDs and tried to learn them like that, but it just didn’t work for me.” It’s fair to say that he has come up with a remarkable solution for the many of us who fall into the same boat.
Other quiz options
I should mention a couple of other resources for those wanting to quiz themselves. North American Bird Sounds is an app that offers a variety of both visual and auditory quizzing tools, along with a nice reference library of photos and songs. For my intermediate birding skills, I liked the visual tests better, finding the song quizzes too difficult and random to help me much. The Audubon Owls Guide app also has both photo and audio quizzes of the different North American owl species. Before you try any birdsong quizzing apps, I also recommend checking out Cornell’s Bird Song Hero game on the web. Though short, it’s a good confidence builder and a lot of fun.
One bird at a time
Many other apps offer resources for those wishing to learn about birdsongs. Most of the bird guide apps I reviewed in Part 1 of this series have built-in selections of bird calls, as do more internationally-minded apps such as Bird Calls, which offers libraries from the U.K., Brazil, India, and other hot birding locations around the globe.
The important thing — and I say this to myself as much as I do to you — is to be patient with yourself. When it comes to learning birdsongs, each of us has different capabilities based on age, genetics, background, and hearing damage. As Phil Mitchell told me, “Learning bird calls is really hard,” so give yourself a break. You might never be able to discern an American Redstart from a Townsend’s Warbler by ear, and that’s okay. Just keep at it, start playing around with these fun apps, and watch your bird-listening skills grow.
This article was first published in the January/February 2021 issue of BirdWatching magazine. It has been updated with new information about the BirdNET app.