Many people would say we are currently in the golden age of bird books. As we learn more and more about birds, and that information becomes more and more accessible, a huge number of bird books have been published. We have whole books dedicated to molt, tricky identifications in the Western Palearctic, the birdlife of Jordan, and detailed field guides to everything from Central Asia to Pacific Islands. Despite the stereotypical birder love of print books, however, the information revolution, which has produced such benefit to the bird book world, has also dealt a serious blow to hard copy print.
With smart phones in every pocket and wifi in every building, more and more people are moving away from print books and into the world of digital apps. Consequently, many seminal field guides from the Sibley Guide in the United States to The Collins Bird Guide in Europe have created companion apps. It isn’t a stretch to say that any mainstream field guide aiming to remain relevant and important ought to have some sort of electronic equivalent.
The Warbler Guide, hailed as groundbreaking on its release as a book, is helping lead the way in meshing print media with digital media. The authors released their app for iPhone in 2014 and recently came out with a version for Android; The Warbler Guide app has outdone itself. Unlike most field guide apps, which mostly seek to electronically present the same information as the book, The Warbler Guide has added a number of new features, allowing its app to truly function as a companion to the book, complementing the printed material and adding to it.
Right off the bat, it is important to say that the Android version of the app is essentially the same as the iPhone version. In fact, when I compared the two, I could only find minor layout differences to fit the operating system. So if you liked the app on iPhone but have switched over to Android, there is no need for trepidation about purchasing.

The main thing the app adds to the book is the 3D models feature. The book version’s huge number of photos was one of its main selling points. The app has upped the game, creating 3D models of every warbler species which can be rotated to view the bird from any angle. This becomes even more valuable when you compare similar species as the models rotate simultaneously, allowing easy comparison.

This is a feature I have actually used in the field a number of times, say when I briefly see a basic plumaged Blackpoll or Bay-breasted Warbler. I can easily whip out my phone and compare 3D models of the two similar species from the exact angle I saw the mystery bird in real life. This app couples birding and 3D models brilliantly and, frankly, it’s a shock that it had not been done before. However, there is the downside that the models are lacking in clear resolution and photographic detail.
The second major feature to add to the book is the integration of audio into the app. The book focused on visuals to learn warbler sound, displaying spectrograms of songs and calls. This makes sense in a print format, particularly given that studying spectrograms is an extremely good way to learn birdsong. In addition, the book offered readers a website where they could listen to all the recordings in the book. With the advent of the app, this is no longer necessary as the recordings are imbedded into the app so users can listen to them while looking at the accompanying spectrogram. Not only does this make the app field useable for identifying unknown songs, but it also helps to reinforce what you learn by allowing for simultaneous study of the spectrogram.

Even if you were to exclude those new features though, the app would still be good. It presents the information clearly with easy access to all the photos, maps, aging and sexing information, and similar species as the book. The main page can be sorted alphabetically or taxonomically according to individual taste. Interestingly, also included is an option for ordering the species by color: with mostly blue (or yellow, or brown, etc) warblers grouped together. This would be rather useful for a beginning birder who sees a warbler and doesn’t know where to start when identifying it.

Additionally, the app gives an option to filter species by time of year and range. This is similar to what the Collins Bird Guide has done previously. Again, this feature could be rather helpful for less experienced birders trying to narrow down their options. However, The Warbler Guide has also added filter options for colour of different body parts (allowing you to only see birds with say, black tails) as well as, most interesting, for song, allowing you to select song quality, pitch trend, and number of sections as filters. This is something I haven’t seen done before by bird apps and fits both the book and the app’s innovative approach towards birdsong.

Frankly, one of the biggest advantages of the app is simply that its an app. The book is large and bulky and hard to justify bringing into the field. That is a shame since there as times when it would be genuinely useful to have on hand. However, fit the book into your pocket, as the app does, and it can be accessed anywhere. As mentioned above, there are many situations in which the app can be used in the field like a more traditional field guide; in fact, I have used it myself while out birding. This might even be the strongest thing about the app; it is able to take a large reference book and convert it into a sleek, field-usable guide.

Overall, the app is a very welcome addition. It presents the book’s information in a easy-to-use and convenient way, and adds a number of brilliant new features to what’s in print. Now that it is compatible with Android, The Warbler Guide can reach a whole new host of users and becomes even more utilitarian. Hopefully, future bird app designers will look at The Warbler Guide as an example to be followed.


*Princeton University Press provided a complimentary copy of The Warbler Guide app for this review.