A year later, Cameron Kepler and Kenneth Parkes described the species and named it Dendroica angelae, making it the most recently discovered New World warbler.

[3] In 2011, the American Ornithologists' Union reorganized the classification of the family Parulidae and transferred species in Dendroica to Setophaga.

[7][8] The elfin woods warbler is a small passerine, averaging 12.5 cm (5 in) in length and 8.4 g (0.30 oz) in weight.

[2] Juveniles differ from adults, retaining a grayish-green back for approximately a year and partially molting from July to October.

The species has a subtle voice and its call and song resemble those of the bananaquit, the most abundant bird in Puerto Rico.

[9] While searching for food it often flocks with other birds, such as black-and-white warblers, Puerto Rican tanagers and Lesser Antillean pewees.

Probing is a maneuver in which the bird, by digging with its beak, forages the substrate looking for food in a manner similar to chickens.

The wind-clipped trees in these forests rarely exceed 5 meters (16 ft) in height and are characterized by stiff, thick twigs, leathery leaves and impenetrable, dense undergrowth ideal for hiding from predators.

Later studies showed that the species migrated to lower elevations, between 370 and 600 meters (1,210 and 1,970 ft), in Tabonuco and Palo Colorado forests.

It is found at mountain summits and is primarily composed of dense shrub and small trees with moss and epiphyte growth in its plants and floor.

A survey conducted two years later in the Toro Negro Forest, located in the Cordillera Central, did not find any individuals.

An IUCN assessment of the elfin woods warbler, prepared in 2000, estimated a stable population of 600 mature individuals.

[1][20] The elfin woods warbler faces two main threats: predation, and the destruction or alteration of suitable habitat.

The pearly-eyed thrasher, the Puerto Rican sharp-shinned hawk and the now extirpated white-necked crow are all confirmed native predators.

Introduced species, such as domestic cats and dogs, black rats, and small Asian mongooses, are also potential nest predators.

The construction of communication towers, logging, and the expansion of roads and trails have all caused habitat destruction within the warbler's range.

[22] The International Union for Conservation of Nature (IUCN) first evaluated the status of the elfin woods warbler in 1988.