The two species were originally placed in the New World wood warbler family Parulidae, but taxonomists were unsure if they belonged there.

DNA evidence published in the early 2010s showed they were not related to other wood warblers, and in 2017, they were moved to the newly created family Phaenicophilidae.

There it inhabits broadleaf and pine montane forest with a dense understory at elevations up to about 2,900 m (9,500 ft).

The subspecies M. p. vasta is a disjunct population found in the southwestern Dominican Republic lowlands and Beata Island.

The green-tailed warbler makes "[s]hort rasping and squeaking notes" that may accelerate into what is thought to be its song.

[4] The IUCN has assessed the green-tailed warbler as being of Least Concern, though its population size is unknown and believed to be decreasing.

The main potential threats are continuing habitat destruction and predation by introduced small Indian mongooses.