Tadau Kaamatan is to celebrate thanksgiving to the Bambarayon/Bambahazon(paddy spirit) as to show how grateful and respect to Kinoingan(God) for a very good harvest.
In tradition, it's celebrated during the first full moon after the paddy was harvested and it's celebrated within the village or county.
Now, this may be just a memory or a performance for tourists since more KDM(Kadazandusun and Murut) have converted to Christianity & Islam that it's not really encouraged to participate this kind of ceremony.
It's a pity that there's not much documentation or documentary related to our dying culture and tradition in Sabah. I hope one day, I may have the courage to pack up my camera and a notebook to venture out in Sabah to do this.