Esmeraldas Woodstar

Identificazione

At only about 6 centimeters long, Esmeraldas woodstars are among the smallest species of hummingbird. Researchers recently found Esmeraldas woodstars at twelve new locations and collected the first female specimens of the species. Previously, the specimens labelled as female were misgendered juvenile males.<p>Female Esmeraldas woodstars have yellowish-brown underparts and a dark greyish-black back, head, and tail. They have green patches on the sides of their chest and the center of their tail. Their tails also have small, cinnamon-rufous tips. They have a white postocular stripe (differently coloured feathers extending from the eye down to the neck). Little woodstars inhabit the same region as Esmeraldas woodstars, and the females of both species appear very similar to each other. Distinguishing features of little woodstar females are their green sheen, cinnamon postocular stripe which is short and narrow (rather than long and wide), cinnamon underparts, and larger size.<p>Male Esmeraldas woodstars have green upperparts with a blue sheen, white underparts, a white postocular stripe, a green chest band, a forked tail and a bright purple throat. Male little woodstars also appear very similar to male Esmeraldas woodstars. In contrast, male little woodstars have ruby-pink throats and are greener on both their upper- and underparts.<p>Male juvenile Esmeraldas woodstars were previously misidentified by researchers as adult females because of their similar appearance and extremely small gonads. Male juveniles have white underparts, a yellowish-brown throat with a few purple feathers, and a distinctive rounded, green tail with a rufous-cinnamon base and pale cinnamon to whitish tips. Young Esmeraldas woodstars that are still nest-bound have yellowish-brown underparts with green and cinnamon wings. Male Esmeraldas woodstars that have recently left their nest are similar to male juveniles but without the purple feathers on their throat.

Tassonomia

The Esmeraldas woodstar belongs to the family Trochilidae and the genus Chaetocercus. There are six species in this genus: the Esmeraldas woodstar (C. berlepschi), the white-bellied woodstar (C. mulsant), the little woodstar (C. bombus), the Santa Marta woodstar (C. astreans), the gorgeted woodstar (C. heliodor), and the rufous-shafted woodstar (C. jourdanii). Previously, these species (besides the rufous-shafted woodstar) were categorized in the genus Acestrura. They were reclassified into the same genus due to their extremely similar morphology. Overall, the Chaetocercus genus is poorly understood. Woodstars are difficult to study because of their small size and elusive behaviour, particularly during non-breeding season.

Nome scientifico

Chaetocercus berlepschi

Autorità

Simon, 1889

Ordine

Apodiformi

Famiglia

Trochilidae

Genere

Chaetocercus

Areale e habitat

Esmeraldas woodstars are found only on the Pacific coast of western Ecuador. They occupy a small range which has been mostly deforested. Their range overlaps with the little woodstar. Esmeraldas woodstars inhabit semi-deciduous to evergreen moist forests. They are found anywhere between sea level and 750 meters in elevation. This includes both low elevation areas which have been disturbed by human settlement, and undisturbed, high elevation areas.

Migrazione

Specie stanziale

Comportamento

Comportamento migratorio: Specie stanziale.

Conservazione

Tendenza della popolazione: in diminuzione.

Tendenza della popolazione

in diminuzione