Scandinavian folk and softer folk metal (no, try them before you >imply manchild):
http://www.youtube.com/watch?v=ku5D_L-OIkIThis particular type of singing is called "kulning" and is used to call livestock from great distances. It was particularly used by people living in fäboddrift in Scandinavia, driving livestock greater distances in forests or fells.
(example when done across a lake here:
http://www.youtube.com/watch?v=4B1l94ffv6s)
http://www.youtube.com/watch?v=S_g0bUzMTLchttp://www.youtube.com/watch?v=URnu49H-YUkhttp://www.youtube.com/watch?v=zg1zAaDytYoand some more ambient stuff like
http://www.youtube.com/watch?v=vi4DKoh4Z80