Over the years since I posted this script, it has become more and more common to scrape audio files off of Xeno-Canto.org. This has resulted in an overwhelming amount of traffic to their servers.
Please do not scrape Xeno-Canto without contacting the organizers first to ask for permission and for more information. They will be able to advise you on the best time of day to download data from their servers, or any alternative download options that are available.
Hi Dominik! To be honest, I should probably make this script private. It's from a while ago. Since I created it, it has become much more common to scrape Xeno-Canto and it is overwhelming their servers. So, the Xeno-Canto folks ask that you refrain from scraping it to the extent possible.