Data Zone
Justification of Red List category
This species is restricted to a moderately small area in southern Mexico; it is suspected to have a small population. Habitat within the range is lost at a slow rate, which is thought to cause the population to decline. The species is therefore listed as Near Threatened.
Population justification
The population size is preliminarily suspected 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.
Trend justification
The species is undergoing a slow decline due to the loss and degradation of its montane forest habitat (Partners in Flight 2019; Arizmendi et al. 2020). Tree cover loss within the range has been low (1% over ten years; Global Forest Watch 2021). It has been hypothesised that 15-49% of the total population has been lost during the period 1970-2017, based on assessments of habitat loss (Partners in Flight 2019; Arizmendi et al. 2020). Assuming a constant rate of decline, this averages to a decline of 3-13% over ten years. In view of the ongoing threats, this is suspected to continue at a similar rate into the future.
Eupherusa poliocerca is fairly common to common (Howell and Webb 1995; M. Reid in litt. 1998) but extremely local on the Pacific slope of the Sierra Madre del Sur in Guerrero and west Oaxaca, south-west Mexico. Most records in Guerrero are from near Omiltemi and along the Atoyac de Alvarez-Teotepec road (e.g., Navarro 1992), but it has been recorded further west, inland from Zihuatanejo. The species requires montane forests, which cover a total area of 5,600 km2 within the range (Global Forest Watch 2021).
It inhabits cloud-forest, evergreen subtropical and semi-humid forest, forest edge and adjacent coffee fincas at elevations of 800-2,440 m (Howell and Webb 1995). It is probably marginal or seasonal at the lower altitudes (below 1,200 m) in the ecotone between tropical semi-deciduous forest and cloud-forest. The species requires intact, pristine forest (Arizmendi et al. 2020). It feeds on a variety of flowering plants, but is subordinate to other hummingbirds in its range (T. Züchner in litt. 1999). Breeding season peaks are likely to be February-May and September-October (Arizmendi et al. 2020).
It tolerates some habitat degradation adjacent to suitable forested habitats, but lower montane forests are being widely cleared for corn, fruit and coffee (Dinerstein et al. 1995), with forests at higher elevations being destroyed by cutting for lumber. Areas near Putla de Guerrero are now heavily deforested and further degraded by goats (Wege and Long 1995).
Conservation Actions Underway
CITES Appendix II. This species is on the watch list as part of the State of North America's Birds (North American Bird Conservation Initiative 2016).
11 cm. Medium-sized, green hummingbird with distinctive tail pattern. Male largely emerald-green. Mostly black wings with rufous secondaries. White tail with green central rectrices. Female pale grey below with grey ear-coverts and white postocular spot. Less rufous secondaries and outer rectrices edged dusky green. Immature resembles female. Similar spp. Berylline Hummingbird Amazilia beryllina has rufous tail and lacks green belly. Not known to occur sympatrically with Blue-capped Hummingbird E. cyanophrys, in which male has blue crown but females are indistinguishable. Voice Buzzy chip, given in series to become a trill. High, accelerated warbling song.
Text account compilers
Hermes, C., Everest, J.
Contributors
Benstead, P., Capper, D., Isherwood, I., Reid, M., Sharpe, C.J., Taylor, J. & Züchner, T.
Recommended citation
BirdLife International (2024) Species factsheet: White-tailed Hummingbird Eupherusa poliocerca. Downloaded from
https://datazone.birdlife.org/species/factsheet/white-tailed-hummingbird-eupherusa-poliocerca on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/11/2024.