This discussion was first published as part of the 2016 Red List update. At the time a decision regarding its status was pended, but to enable potential reassessment of this species as part of the 2017 Red List update this post remained open and the date of posting was updated.
Setophaga angelae (formerly Dendroica angelae BirdLife species factsheet) is restricted to Puerto Rice (to USA). The species was discovered in 1968 and is now thought to be restricted to two widely separated locations: the Sierra de Luquillo (El Yunque National Forest/Bosque Nacional del Caribe) in the east and Maricao State Forest in the west. In optimal habitat it can be locally common, and although the population was previously thought to be no more than c.300 pairs (Curson et al. 1994), more accurate counts put the population at around 2,700 individuals.
This species’s Extent of Occurrence (EOO) has been revised as c.1,200 km2, based on a Minimum Convex Polygon (the smallest polygon in which no internal angle exceeds 180 degrees and which contains all the sites of occurrence) (IUCN 2001, 2012).
Although the species’s EOO is small enough to meet the thresholds for it to be listed as Endangered under Criterion B, there was previously no evidence that the species was declining and consequently the species did not meet the subcriteria necessary for it to be listed as threatened under Criterion B. The species is currently listed as Vulnerable under Criterion D2 owing to its restricted range.
A study by Arendt et al. (2013) at El Yunque National Forest found that between 1989 and 2006, the S. angelae population density declined from 0.2 to 0.02 individuals/ha in elfin woodland and from 1 to 0.2 individuals/ha in palo colarado forest, possibly as a result of habitat conversion and degradation caused by increasingly regular and more intense cyclonic events in the region. The current trend of the El Yunque subpopulation is unknown and there is no data to confirm that the subpopulation in Maricao Forest and adjacent land has declined, but habitat loss in the adjacent land is ongoing so it is considered probable that the species is declining.
It is therefore proposed to list Setophaga angelae as Endangered under criterion B1ab.
Additional information and comments on this proposal are welcomed.
Arendt, W. J., Qian, S. S., & Mineard, K. A. (2013). Population decline of the Elfin-woods Warbler Setophaga angelae in eastern Puerto Rico. Bird Conservation International, 23(02), 136-146.
Curson, J.; Quinn, D.; Beadle, D. 1994. New World warblers. A&C Black/Christopher Helm, London.