Update, 3/24 2:38 PM PST: James Joiner tweets us that it's a version of "Coyotes" with Lisa Molinaro on vocals.
180 Degrees South, the documentary that Ugly Casanova did the bulk of the soundtrack for back in 2010, followed the journey of Jeff Johnson as he traveled from Ventura, California to Patagonia, Chile.
Johnson and James Joiner are curating and editing a book, produced by Patagonia, entitled Going Out is Going In. The book is limited to 3,000 copies, with 100% of the proceeds going to the charity 1% for the Planet.
A free digital playlist of 43 artists is available for download on the inside cover of each copy. Modest Mouse will be one of those artists and has labeled the track as "an exclusive, never before heard Modest Mouse song."
No word yet on what the track is titled, but we'll update you as we hear more.