The range of distribution of the Lesser Greenlet, Hylophilus decurtatus, stretches from northeastern Mexico south to western Ecuador in the lowlands and foothills up to 1200 m altitude.
There are two races.
- The nominate H. d. decurtatus breeds from central Panama southwards. It has a green crown to the head.
- The grey-crowned H. d. minor occupies the northern part of the bird’s range. The latter subspecies was formerly given species status as the Grey-crowned Greenlet, H. minor but the two forms interbreed extensively in central Panama and are now considered to be conspecific (of, or belonging to, the same species).
The adult Lesser Greenlet is 10 cm in length and weighs 9 g. It has olive-green upperparts and a pale grey head with a white eyering. The underparts are white with a yellow tinge to the breast and some olive on the flanks.
Immature birds are duller and brown above, and have a buff tone to the sides of the head and the breast.
Nesting / Breeding:
The nest is a deep cup of dead leaves and spiderwebs attached by the rim to branches 10-15 m high in a tree. The normal clutch is two brown-marked white eggs.
Lesser Greenlets feed on spiders and insects gleaned from tree foliage, They also eat small fruits and seeds.
The Lesser Greenlet has a nasal neeah-neeah-neeah-neeah call and the song is a whistled chi chi cher cher cher cher chiri cher which cheri, slower and more melodious than that of the Yellow-green Vireo.