It is not standard language. 마가리 is listed as dialect word for a small hut (I've personally never heard it before), and 출출이 (perhaps a bird species) is not even listed in the dictionary. 산골로 가자 = Let's go into the mountains. 출출이 우는 깊은 산골로 가 마가리에 살자 = Let's go deep in the mountains where 출출이(?) chirps and live in a little hut.