The Macaulay Library at the Cornell Laboratory of Ornithology has just released what it’s calling the “Master Set” – the most comprehensive audio guide to North American bird sounds ever published. Totalling 4938 mp3 files of 735 bird species, it’s a doozy of a download – even broken up into three parts and zipped, it still totals a whopping 4.71 gigabytes of audio. It’s a significant development for North American birding. (Full disclosure: I participated in part of the review for this project, and four of my recordings are in it.)

The Master Set has been in the works for a number of years now. It’s intended to be a distillation of the finest audio clips in the collection of the Macaulay Library, the world’s greatest avian audio archive, comprising some 150,000 separate recordings, about 30,000 of which are from North American birds. Remember the gargantuan government warehouse in the final scene of Raiders of the Lost Ark? That’s how I’ve always pictured Macaulay – a trove of hidden treasures, a giant haystack made of needles. The process of creating the Master Set involved reviewing the majority of these recordings in an attempt to find examples for every vocalization type of each species, including individual and regional variations whenever possible.  “This is a celebration of what the recording community has given us,” says Macaulay audio production engineer Matt Young.

Because it extended across many years (and the tenures of multiple Macaulay Library employees), this review process has resulted in many inconsistencies and a few errors in the set. As a result, Macaulay is describing the Master Set as “a work in progress,” one which they intend to correct, update, and expand over time. To purchase the first complete draft of this work in progress, you’ll pay $49.99 – a special introductory price that will rise by $10 at some point soon, according to the website. The Master Set is neither perfect nor complete, but it is the most comprehensive audio collection of its kind to date.

The sound files are accompanied by photos that pop up when you play the audio on many devices – a nice touch. The recordings are accompanied by a short booklet with some introductory text and a list of audio and photo credits, but no additional information about the individual sound files. Some of this information, including the Macaulay catalog number of the source recording, can be found in the MP3 data tags for each file.  As you might expect, not all species are covered in the same detail. There are 39 cuts of Carolina Wren, but “only” four of California Thrasher. (I put “only” in quotes because most commercially available audio collections don’t even give you four cuts per species.) This gives you some idea of the scope of the work.

For those who don’t want to wade through 22 Tufted Titmouse cuts simply labeled “song,” there’s a smaller, more manageable version of the collection: the Essential Set, comprising 1376 cuts of 727 species, for $12.99 (that price to rise by $7 at the end of the introductory offer period).

If you find errors while exploring the collection, send an email to MLproductions@cornell.edu.  I presume you can use the same address to write with kudos for getting this massive undertaking off the ground — it’s been a long time coming!