Eastern slope of Andes in Ecuador (Napo south to at least Morona Santiago, perhaps to Zamora-Chinchipe) and Peru (San Martín, and from Huánuco south to northern Junín).
 
Population
Estimated population is unknown (2010).
Habits
Singly or in pairs. Occasionally observed with other species, usually inconspicuous.
Voice
A distinctive loud 'swee-swee-swee' with 10-12 notes repeated. Scrub Greenlet (Hylophilus flavipes) either has a disyllabic note, eg 'turee-turee-turee' repeated 4-20 times, or a more slurred, slower double note in Central America.
Olivaceous Greenlet (Hylophilus olivaceus) [XC275113]
by Ross Gallardy from Napo: Narupa, Ecuador (song, song (2 types))
Olivaceous Greenlet (Hylophilus olivaceus) [XC296708]
by Fabrice Schmitt from Villa Rica area, Pasco (Hacienda Carmen), Peru (song)
Subspecies
No subspecies.
Forms a superspecies with Scrub Greenlet (Hylophilus flavipes) and sometimes considered conspecific.
Similar Species
Sometimes considered conspecific with Scrub Greenlet (Hylophilus flavipes) and the two are very alike. Scrub Greenlet (Hylophilus flavipes) may be darker on forecrown, and paler greyish white on the chin and throat.
References
See References.