They are beautifully marked with bright coloring. The adults have bright red bills and a dull yellow ring around their eyes. Their backs are dull olive green and have a bright yellow-orange throat with a yellow chin. They have forked tails. Female Leiothrix are similar to males but with a duller shade.
Juveniles have black bills and gray coats.
This Leiothrix is also known for it's vocalizations. It sings loud, melodious songs. Red-billed Leiothrix are native to Southern Asia and are now found on the Hawaiian Islands. These birds were first introduced to Kauai in 1918. Sometime later, these birds were introduced to the other islands.