The dusky-capped greenlet (Pachysylvia hypoxantha) is a species of bird in the family Vireonidae, the vireos, greenlets, and shrike-babblers. It is found in Bolivia, Brazil, Colombia, Ecuador, Peru, and Venezuela.
The dusky-capped greenlet was originally described in 1868 as Hylophilus hypoxanthus. For a time early in the twentieth century it was considered a subspecies of the golden-fronted greenlet (P. aurantiifrons) but beginning in the 1930s it attained its status as a full species.
The dusky-capped greenlet has these six subspecies:
Some mid-twentieth century authors treated P. h. inornata as a subspecies of the brown-headed greenlet (Hylophilus brunneiceps). Subspecies P. h. flaviventris was described as a full species and often treated that way until the mid-twentieth century.
The dusky-capped greenlet is long and weighs about . The sexes have the same plumage. Adults of the nominate subspecies P. h. hypoxantha have a dull olive-brown forehead, crown, and nape. Their back is buffy olive and their rump a brighter yellowish olive. Their wings' primaries and secondaries are dull blackish gray with greenish edges on the outer webs. Their tail is yellowish olive with brighter edges on the feathers' outer webs and bases. Their chin and throat are dull buffy whitish and the rest of their underparts are pale yellow with a slight buffy wash.
The other subspecies of the dusky-capped greenlet differ from the nominate and each other thus:
All subspecies have a gray-brown iris, a dark brown maxilla, a pale brown or pinkish mandible, and gray legs and feet.
The subspecies of the dusky-capped greenlet are found thus:
The dusky-capped greenlet inhabits humid terra firme and várzea forest, where it favors the subcanopy and canopy. In Brazil it ranges in elevation from near sea level to . It reaches in Colombia, is mostly below in Ecuador, and reaches in Peru and at least and probably higher in Venezuela.
The dusky-capped greenlet is believed to be a sedentary year-round resident.
The dusky-capped greenlet's diet has not been fully examined but is known to include adult and larval insects. It feeds actively, often hanging upside-down to glean prey from leaves. It usually forages in pairs and frequently joins mixed-species feeding flocks.
Nothing is known about the dusky-capped greenlet's breeding biology.
The dusky-capped greenlet's song has been described as a "very high, cheerful is-it-so-wit or pichÃÂ-soweér". Its call is "a wheezy dee-dee".
The IUCN has assessed the dusky-capped greenlet as being of Least Concern. It has a very large range; its population size is not known and is believed to be decreasing. No immediate threats have been identified. It is considered "uncommon" in Colombia, "obscure" in Ecuador, "widespread and fairly common" in Peru, and "common to frequent" in Brazil. It is known in Venezuela from only a few records.