Although the Olive Warbler has long been associated with the New World wood-warblers (Emberizidae: Parulinae), evidence from anatomical and DNA studies suggests it is not a warbler at all, instead placing this species in its own monotypic family, Peucedramidae, a family that lies outside the radiation of passerines with nine primaries. Surprisingly, given historical arguments about phylogeny, recent molecular studies suggest that the Prunellidae, the small Old World family of accentors, is the Olive Warbler's nearest extant relative (see Systematics).
The Olive Warbler is an oscine with orange-brown head and 9 primaries that is generally found in pine forests of high mountains from Nicaragua north into central Arizona and southwestern New Mexico. Also found in mixed pine-oak (Pinus-Quercus) woodlands, it uses pines almost exclusively for foraging and nesting. Males, at least of northern populations, require 2 years to acquire full adult plumage. Although relatively common, this species has been studied little in the field. It is a bird of the high canopy that nests far out on high branches of pines; F. C. Willard ( Willard 1910c ) described a 5-hour effort of climbing within a single tree to find one nest. Discovery of other aspects of this species' breeding biology also require much effort for small sample sizes. Many of the observations reported here are anecdotal or were incidental to other studies; few stem from studies in Mexico, which contains most of the species' range (see Figure 1).
This warbler has been properly associated with the specific name taeniatus only since 1948 ( Zimmer 1948 ). Older literature refers to the Olive Warbler as either Dendroica olivacea or Peucedramus olivaceus.