Justification of Red List Category
This species has a small population size, which is considered to be in declines as a result of continuing habitat loss. Therefore, it is listed as Vulnerable.
The population size is preliminarily estimated to fall into the band 10,000-19,999 individuals. This equates to 6,667-13,333 mature individuals, rounded here to 6,000-15,000 mature individuals.
The species's population is thought to be declining slowly, in line with the on-going clearance of forest for agriculture within its range.
Thalurania ridgwayi is patchily distributed in south Nayarit, Jalisco and Colima states, west Mexico, where it is uncommon to locally common. Surveys in central and south Mexico have failed to find the species. Therefore its restricted range is likely not a result of incomplete knowledge.
It occurs in humid, semi-deciduous woodland and shade coffee plantations at elevations of 250-1,200 m. Its ecology is poorly known, but it is often found along streams and generally avoids edge habitats (Howell and Webb 1995).
The reasons for this species's patchy distribution, as well as its precise ecological requirements, are poorly understood. The avoidance of edge habitats indicates that it is probably threatened by habitat destruction. Forests within its range are cleared mainly for conversion into plantations for sun coffee.
Conservation Actions Underway
CITES Appendix II. The species is recorded in three protected areas: Cerro San Juan Special Biosphere Reserve, Nayarit; Sierra de Manantlán Biosphere Reserve, Jalisco/Colima; and Nevados de Colima National Park, Jalisco/Colima (Wege and Long 1995). The species is on the watch list as part of the State of North America's Birds (North American Bird Conservation Initiative 2016).
10 cm. Medium-sized, mainly green hummingbird with black wings. Male has iridescent blue forehead and bluish-green hindcrown, iridescent emerald throat and slightly forked, bluish-black tail. Female green above with small, white postocular spot, greyish below with green discs on flanks. Bluish-black tail with white tips to outer rectrices and green central rectrices. Straight black bill. Immature unknown. Similar spp. Male Broad-billed Hummingbird Cynanthus latirostris has red bill, blue throat and lacks blue crown, female has dusky red bill and noticeable white postocular stripe. Berylline Hummingbird Amazilia beryllina is pale below with rufous tail and wing-patch. Voice Fluid rattling notes and trills.
Text account compilers
Isherwood, I., Capper, D., Benstead, P., Sharpe, C.J., Taylor, J., Westrip, J.
BirdLife International (2023) Species factsheet: Eupherusa ridgwayi. Downloaded from http://www.birdlife.org on 22/03/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/03/2023.