It took archivists a dozen years to complete the monumental task. The collection contains nearly 150,000 digital audio recordings equaling more than 10 terabytes of data with a total run time of 7,513 hours. About 9,000 species are represented. There’s an emphasis on birds, but the collection also includes sounds of whales, elephants, frogs, primates and more.
Even with those thousands of hours of recordings, some contemporary species remain unrecorded. The library maintains a list of their most wanted calls. On the list for North America are the Arctic Loon, Shiny Cowbird, and Surf Scoter. (via @alexismadrigal)