Bihu, an Assamese folk festival celebrates the jubilant three seasons that marks the beginning, middle and end of a year in the Assamese calendar. Rongali or Bohag, Kati or Kongali and Boghali or Magh Bihu, namely are celebrated at different times in the year and each one of them has a significant role in telling stories of the agrarian community. The folk songs assume great significance since they reflect the correct sentiment amongst the natives and further narrate the significance of the season.

The Folk songs associated with Bohag Bihu are called Bihu Geets or Bihu Songs. The sights of “Mukoli Bihus” are often during the month of April - the month celebrated by all age groups as the arrival of spring. Romance and songs of merriment occupy a central place amongst the young boys and girls as they get together in open spaces dancing and singing to the tunes of Bihu. Dhol, Gogona, Pepa, Sutuli and Bihu Taal are five major musical instruments used to compose tunes of Bihu Geet. 

For more details:
https://www.dsource.in/resource/popular-folk-musical-instruments