I'm still going with lumberjack (per my post yesterday), a lumberjack who works on a mountain. If the dictionary gives 'jack' as an shortened version of 'lumberjack', the whole word isn't necessary in the song and somebody can stick 'mountain' in there. Donkeys are nice, but they don't holler so much as bray, and mountain lumberjacks would have to holler 'timber' pretty loud.