Immatures are a slightly duller black than adults and the white areas are not as prominent.

The other includes eastern Peru, northern Bolivia, and western Brazil as far east as the upper Purus River.

[4] The yellow-billed nunbird's feeding behavior and diet have not been extensively studied.

It appears to hunt by sallies from a high exposed perch, catching its prey in the air.

The yellow-billed nunbird's song "consists of full melodious lengthy phrases in choruses, typically including a frequently repeated 'wheekit-wheeyk, wheekit-wheeyk...'.