Original Soundtrack composed by: Jeffery L. Briggs, Ken Lagace and Roland J. Rizzo
Amiga Soundtrack by: Allister Brimble and Anthony Putson
It's a tune without much in the way of instruments besides a drum and pipes, but that's because it's trying to emulate the tribal sound of North America's native population (although whether it succeeds or fails miserably, you'd have to ask someone who is knowledgeable of Native American music from tribe to tribe). This track plays as background music while you navigate the main menu for Sid Meier's Colonization but it also plays the first time you meet the native population of the New World too.
EDIT (15/10/2016): A fellow YouTube user +Plastiware has alerted me to the fact that despite me originally advertising these tracks as the Amiga version of the soundtrack, it's probably not entirely accurate. I originally marked these as the Amiga version due to the source MP3s I used stating Allister Brimble and Anthony Putson as the composers, but when comparing these tracks to Amiga versions of the soundtrack on YouTube and then comparing it to a DOS CD version, it seems these are most likely from the DOS CD version. Apologies for the mistake.
[ VIDEO: Choicest VGM - VGM #230 - Sid Meier's Colonization - Natives ]