How to use the Merlin App for birdwatching

Developers release new outdoor mobile apps all the time. If you’re learning birds, Cornell Lab of Ornithology‘s birding app Merlin is one you can’t miss. The app’s new features provide great tools for birdwatchers of all skill levels. Since being a beginner birdwatcher can be especially challenging, it’s important to recognize how these can help people that are just starting out. In this Birdwatching Basics post, I’ll provide a brief guide on how to use the Merlin app to watch birds in your backyard and beyond. If you’d like to hear more about Merlin, check out the Nature Guys podcast episode, Merlin magic.

A field guide in your pocket

At its most basic level, Merlin acts like a digital field guide to North American birds. In other words, it has a searchable database of information on birds in your area. Using the GPS on your phone, it will provide information on the common birds in your area. Using the “Explore Birds” button from the home screen, you can browse these species.

Just like in a field guide, you can see pictures, descriptions, and maps to help you learn about individual birds. The app will even provide lists of similar-looking species to help you sleuth out any ambiguous sightings. All this without the added weight of a book! Taking a step beyond field guides, the app allows you to listen to recordings of birdsongs to help you recognize them in the future.

Important note: While scientists may sometimes play bird songs to get wild birds to approach them, you should never do this without a permit. Playing a species’ song to a singing individual in its territory will cause the bird stress that could interfere with nesting. Consequently, it is never acceptable to use playback of bird songs for recreational birding. Instead, enjoy the challenge of birdwatching and find other ways to get a good look!

Asking the right questions

how to use the merlin app
The number of species in a field guide can be overwhelming. Merlin can help narrow down your choices based on your observations.

Another basic feature of Merlin is a questionnaire to help you narrow down a bird sighting to a list of most likely suspects. This is fantastic, because, especially for beginner birdwatchers, an entire field guide full of birds can be rather daunting. For instance, looking at the dozens of duck species that can be found in Georgia, I might not know where to start if I saw a small brown duck at my local pond. To help with this, you can select “Start Bird ID” from Merlin’s home menu, and you’ll get 5 questions:

  • Where did you see the bird?
  • When did you see the bird?
  • What size was the bird?
  • What were the main colors?
  • What was the bird doing (Was the bird…?)

Let’s explore these questions, how to answer them, and why they matter.


how to use the merlin app

Knowing where you saw a particular species is a great first step in identifying it. This is true whether it’s a plant, bird, fungus, mammal, or bug. This is because different species specialize in different types of habitats, or live in specific parts of the world. By describing natural spaces as different biomes or habitats, you can narrow down what species you are most likely to run into. With Merlin, you can either let it determine your location via GPS, or use a map to highlight where you saw the bird.


Nature involves a lot of timing. Some species will only be around at certain times of year. As a result, it’s important to know when exactly you had your bird sighting. Furthermore, it’s better to answer this question after establishing where the sighting happened, because elevation and latitude affect nature’s timing. Here, you can tell Merlin approximately what time of year you saw the bird, and it will further narrow down its suggestions.

How big was it?

how to use the merlin app

Knowing a birds’ size is a great place to start. However, even with a good pair of binoculars, the size of a bird can be difficult to describe. For instance, looking at the measurements provided in a field guide, it might be hard to tell if a thrush in a tree above you was 16 or 20 centimeters long.

One thing that I love about Merlin is that it offers objects based on commonly known bird sizes. Was it bigger than a robin? Was it smaller than a goose or a duck? This is an easy way to narrow things down without being too specific.

What color was it?

Color is a major part of the bird world, and one of the first field marks that experienced birders use for identification. Merlin allows you to select colors that you saw on the bird to highlight certain possible species.

What was it doing?

One of my favorite things about watching wildlife is observing their behavior. As it turns out, some behaviors can be diagnostic. In other words, certain behaviors are associated with particular species, and you can use them for identification. By describing what a bird was going when you saw it, you can often narrow down your list further. For example, was it flying a certain way, or perhaps singing? These details can be a big help.

Photo and Sound ID

The most exciting new features of the Merlin app use artificial intelligence (specifically machine learning) to automatically identify pictures or sound recordings of birds. This means that if you manage to get a photograph of a bird, or hear it singing, Merlin can use a database of images and sounds to attempt identification. The algorithm looks for similarities in the image or sound structure to other records in its database. Importantly, it can also improve over time.

Although it can be hard to get a good picture of a bird on your phone, the photo feature works great if you get a clear shot. However, I tend to use the Sound ID feature a lot more, and I highly recommend it. When you use the Sound ID feature, Merlin activates your microphone and records incoming sounds.

If it detects songs that it can identify, it will begin listing the birds it hears. It will even highlight that bird in real time as it hears the sound. You can keep your recordings, and also report those sightings to eBird if you are keeping lists of what you’ve seen.

how to use the merlin app

This feature is fantastic for helping you learn birdsongs and calls in real time. It can also be an excellent way to test your skills! I typically wait before turning it on, unless I hear something that really baffles me. That way, I can guess what species I am listening to, and then test myself and see how I do.

Thanks for reading how to use the Merlin app!

Now that you’re familiar with how to use the Merlin app, go try it in your area! See if it can help you sharpen your birding skills or help a friend get into this exciting hobby. If you have questions about this or other outdoor apps, please let me know in the comments or via the Contact page. Thanks for reading, and until next time!