This is a collection of the waiata (folk songs) of Maori: http://www.folksong.org.nz/waiata.html
Consider also playing some titi torea, Māori stick games.
This is one of the late Hirini Melbourne's nature songs. More info on Hirini Melbourne here:
http://folksong.org.nz/tihore/index.html#HirKoromiko
Perfect piece to add ostinato; listen for the stick on the backing track.
About halfway down you will find the song, under resources:
http://artsonline2.tki.org.nz/resources/units/music_units/into_music_1/singing/koromiko.php
Koromiko, Karaka, Ti Kouka Lowland Hebe,
Karaka, Cabbage Tree
Nga rakau o te ngahere The trees of the forest
Nga rakau o te ngahere The trees of the forest
Tarata, Ngaio, Totara Lemonwood, Mousehole tree, Totara
Nga rakau o te ngahere The trees of the forest
Nga rakau o te ngahere The trees of the forest
Titiro ki nga puawai Look at the flowers
Titiro ki nga rau Look at the leaves
He rereke tenei i tena There’s a difference between this one and that one
He rereke, he rereke They are different, all different
He rereke, he rereke All unusual, all unique
Nga rakau o te ngahere The trees of the forest
Nga rakau o te ngahere The trees of the forest
Tarata, Ngaio, Totara Lemonwood, Mousehole tree, Totara
Nga rakau o te ngahere The trees of the forest
Nga rakau o te ngahere The trees of the forest
Titiro ki nga puawai Look at the flowers
Titiro ki nga rau Look at the leaves
He rereke tenei i tena There’s a difference between this one and that one
He rereke, he rereke They are different, all different
He rereke, he rereke All unusual, all unique
