• The Power of Suggestion Part II: The Wizards behind Merlin Sound ID

    By Ryan Nakano

    Two weeks ago I wrote about Merlin Sound ID in response to a long-time member’s inquiry about the automated bird identification tool’s accuracy. At best the article captured the use cases for such an incredibly powerful tool in light of its imperfections and within the context of learning to identify birds. At worst, it flushed readers due to the article’s unnecessary length, or worse still, flushed beginner birders from using Merlin Sound ID out in the field.

    I hope it was more the former and less the latter, regardless, I never answered the original question that prompted the article in the first place — how accurate is Merlin Sound ID? 

    Hence, Part II. This go around I went straight to the source and spoke to one of the many wizards behind the magic — Lead Developer of Merlin Sound ID, Dr. Grant Van Horn. 

    Alright bird nerds, time to get in the weeds on machine learning, recall, precision, and pattern recognition. 

    Q: How accurate is Merlin Sound ID? 

    GVH: “Because we’re running in real time and the metrics we care about revolve around recognizing every vocalization being produced, we have to optimize two metrics: precision and recall. This notion of “accuracy” is a term that is convenient for English speakers but it doesn’t quite match the machine learning requirements.”  

    According to Van Horn, precision in this case is concerned with how often Merlin correctly identifies the presence of a particular bird species (the inverse being a false positive). Whereas, recall is concerned with how often Merlin detects the presence of a particular bird species to begin with (the inverse being a false negative). 

    As far as Merlin Sound ID is concerned, the tool’s baseline goalpost is 90% precision and 70% recall for every bird species its currently trained on. What this means in layman’s terms, is that when you hit record on Merlin Bird ID and it picks up a bird vocalization, 9 times out of ten it will have predicted the correct bird species and when you hear a bird species vocalize, 7 times out of 10 Merlin will be confident enough to make a prediction. Again these are the baseline metrics that Merlin Sound ID is checked against by its designers and will vary from species to species in “accuracy”. 

    Ultimately of course, the goal is 100% on both metrics for all bird species, but this is the standard set for the tool in order to release a particular species into the wild (Merlin-user community) so to speak. …

  • The power of suggestion: Birding in the Age of AI

    By Ryan Nakano

    Whenever I hear the phrase “the power of suggestion”, I immediately think of magic, or rather, the role of the magician. Suggestion allows the magician to influence our perceptions in order to pull off stunning feats that feel real, sometimes real enough to make a lasting impression on the way we see the world. For birders in the modern age, just like townsfolk in the Arthurian legend, the most prominent and powerful magician hands-down is the one and only Merlin. 

    When an email “Is there any data on Merlin Sound ID accuracy?” apparated out of thin air and into my inbox from our GGBA listserv, I clicked and disappeared down a rabbit hole.

    Note: This blog does not answer the original poster’s question (apologies Steve). Rather, what started as a single question, multiplied very rapidly into a steady stream of questions, aka, more rabbits — how does Merlin sound ID even work? If a bird chirps in a forest but only AI identifies it, can it really be listed? If you only use Merlin are you truly “birding”? What does using AI mean for your potential to learn bird species? Maybe more importantly, what might using AI mean for our relationship to birds, other birders, and nature in general?

    The Reveal

    Okay, before we get back to the rabbit hole, it feels important to break the cardinal rule for all magicians, we must reveal (at least slightly) how the act is done. In this case, we must explain what Merlin Sound ID is and how it works. 

    Merlin Sound ID, is an AI machine learning feature of Cornell Lab of Ornithology’s Merlin Bird ID App. The Merlin app more generally, assists users in identifying birds from live recordings (Merlin Sound ID), by your photos, and through other tools like its “step-by-step” function, using location and observed field markings. 

    For the purposes of this blog, pay no mind to the other features. We are only here for Merlin Sound ID. 

    Trust me, it’s more than enough. 

    The Merlin Sound ID works by capturing your recording in the field in real-time, mapping the frequencies in the recording visually via a spectrogram. Enter — magic, or, the power of suggestion. 

    The Macaulay Library holds nearly 2.4 million sound recordings of birds, making it the largest repository of bird audio in the world. Using a machine learning model (deep convolutional neural network, whatever that means), Merlin Sound ID has been trained on at least 140 hours of bird audio from the Library that’s been tagged by sound ID experts to correspond to specific species.…

  • Ear Birding with LightHouse for the Blind and Visually Impaired

    By Helen Doyle, Jeanette Pettibone, and Daniel Scali

    Dan interrupted us halfway around our introductory circle. “Did you hear that?” Several people had heard the bird chipping nearby. For those who didn’t, Dan tried to orient the group: “Off to the left, a little in front of me.” We remained quiet, listening for the chip notes. Golden Gate Bird Alliance’s (GGBA)s first birding field trip with Lighthouse for the Blind and Visually Impaired, an organization that “promotes independence, community, and equity created by and with blind and low vision people,” took place on October 25, 2024 during Birdability Week. It all started with listening.

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    A group of eight people and one dag talking in a circle outside.Trip leaders Dan Scali (left) and Jeanette Pettibone (right) with new birders from LightHouse. Photo @ Helen Doyle

    Listening can be a challenge at Salesforce Park, an urban rooftop park located in the busy SOMA neighborhood of downtown San Francisco. Although it’s four stories above the street, the sound of trucks, buses, and sirens below forced us to concentrate in order to block out background noise. Despite the noise, trip leaders Dan Scali and Jeanette Pettibone chose this birding hotspot for its central location, accessibility, and ability to bring in other sensory experiences. The flat, wide, paved path that loops the park is bordered by a waist-high railing with a wealth of plants native to California and other Mediterranean climates within reach. This offered opportunities for the participants to feel, smell, and for some, see, the leaves and flowers of the plants hosting birds.

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    A group of eight people, some with white canes. on a pathway in a park.The group explores plants as well as birds at Salesforce Park. .
    Photo @ Helen Doyle

    We identified 11 bird species, mostly by ear. The chip notes of a Yellow-rumped Warbler, the chattering of White-crowned Sparrows in a bush four feet in front of us, the electric buzz of Anna’s Hummingbirds flying overhead, the typewriter-like sounds of a Ruby-crowned Kinglet. As much as the sounds themselves gave a clue to the bird’s identity, so did the location. The sparrows stayed in the bushes or foraged for food on the grassy lawn. The Black Phoebe flew quickly over the lawn from its perch and back, catching flying insects in midair. The warblers stayed higher in the trees. For each bird, Dan and Jeanette described the sounds, location, behavior and appearance, including color, patterns, and size.…

  • The Man-Made Mess of Meeker Slough

    By Ryan Nakano and Jeni Schmedding

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    Ridgway’s Rail / Rachel Lawrence

    As the sky awakens at Meeker Slough, a beautiful array of colors backdrop the channeled saltwater marsh. The morning calls and the elusive and endangered Ridgway’s Rail respond with a round of applause, “Kek kek kek kek” as if to acknowledge each new dawn as nothing short of a miracle.

    And in many ways it is a miracle for these olive-brown and cinnamon-colored hen-sized birds, skulking and skittering about, probing the mudflats with their lean orange beaks.

    “Right here, where the bay meets the land and these tidal wetlands occur, that’s where the Ridgway’s Rails live and thrive,” wildlife biologist and Ridgways Rail Monitoring Manager Jen McBroom said. “Unfortunately, we’ve lost 85% of our tidal wetlands in the bay since we started developing these shoreline habitats.”

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    Ridgway’s Rail at Meeker Slough / Alan Krakauer

    McBroom, who’s been officially monitoring the Ridgway’s Rail population with Olofson Environmental Inc. for the past decade, detected 17 rails in total with her team during this year’s most recent survey, making Meeker Slough and neighboring Stege Marsh, one of the densest Ridgways Rail habitat in the Bay Area. 

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    Map of Ridgway’s Rail observations in 2023 California Ridgway’s Rail Surveys for the San Francisco Estuary Invasive Spartina Project by Olofsen Environmental Inc. .kb-image66786_a2f696-11.kb-image-is-ratio-size, .kb-image66786_a2f696-11 .kb-image-is-ratio-size{max-width:668px;width:100%;}.wp-block-kadence-column .kt-inside-inner-col .kb-image66786_a2f696-11.kb-image-is-ratio-size, .wp-block-kadence-column .kt-inside-inner-col .kb-image66786_a2f696-11 .kb-image-is-ratio-size{align-self:unset;}.kb-image66786_a2f696-11{max-width:668px;}.image-is-svg.kb-image66786_a2f696-11{-webkit-flex:0 1 100%;flex:0 1 100%;}.image-is-svg.kb-image66786_a2f696-11 img{width:100%;}.kb-image66786_a2f696-11 .kb-image-has-overlay:after{opacity:0.3;}
    Map from UC Berkeley Richmond Field Station

    For this reason, among many others, Meeker Slough on the southend of the Richmond shoreline, is a critically important place to protect, a place full of promise, full of hope, and unfortunately, full of trash. 

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    Ridgway’s Rail in tire at Meeker Slough / Rick Lewis
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    Shopping carts and other debris in Meeker Slough / Jeni Schmedding

    Among the rails, ducks, herons, and other wildlife, and below steady streams of cyclists, joggers, and dog walkers on the SF Bay trail, sit large truck tires, half-submerged shopping carts, and all matter of junk in the mudflats past the slough’s perimeter fence. …

  • The Vanishing Chorus: A Reflection on North American Birds in Decline

    by Kenneth Hillan

    Wilson’s Warbler, Roys Redwoods Preserve, Spring 2025 – Kenneth Hillan

    In the bustling and growing town of Paisley, Scotland—the place of my birth—a young Alexander Wilson once wandered the woodlands, unaware that his journey would lead him across the ocean to North America. From his letters home, what he encountered in the New World was beyond anything he had known or imagined: skies teeming with birds, forests alive with song, rivers echoing with nature’s pulse. Two centuries later, I reflect on Wilson’s experience—and the troubling question: what remains of that magnificent abundance today?

    On May 1, 2025, a landmark study, published in Science, revealed a sobering truth1. Of 495 North American breeding bird species, fully three-quarters have declined significantly in some part of their range over the past 15 years. The research, led by Alison Johnston and a team at the Cornell Lab of Ornithology, is based on an analysis of nearly 37 million eBird checklists submitted by observers between 2007-2021. The conclusions from the research, grounded in rigorous data analysis combined with national as well as local habitats, paint a portrait of a continent in quiet crisis. A summary of key findings and takeaways from their publication can be found in a one page summary here.

    Curiously, the decline is not always where one might expect. Some species appear to thrive in fragmented habitats—perhaps a mall here, a restored marsh there—offering the illusion of recovery. But these modest gains, while welcome, are dwarfed by losses in the vast habitats where these birds are most common, as populations are declining most severely where they are abundant.

    What sets this study apart is its use of fine-scale trend mapping—measuring bird population change in grids of approximately 10 square miles, rather than just looking across broad regions. This higher resolution has revealed a more nuanced picture: while most species are declining, many also show areas of local increase. For conservation groups like GGBA, this represents a powerful shift. It allows us not only to target urgent declines but also to identify and build upon local successes—guiding action where it can be most effective.

    In the San Francisco Bay Area and the Central Valley, the study data highlights significant declines in wetland and coastal breeding birds, mirrored by parallel losses in the wintering populations of local species that breed in the North American Arctic.

    Here in California, birds that depend on wetlands for breeding have been among the hardest hit.…