Data Zone
Justification of Red List category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence under 20,000 km² combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (under 10,000 mature individuals with a continuing decline estimated to be over 10% in ten years or three generations, or with a specified population structure). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (over 30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern.
Population justification
The global population size has not been quantified, but the species is reported to be locally common (del Hoyo et al. 2001). This species is considered to have a high dependency on forest habitat, and tree cover is estimated to have declined by 11.9% within its mapped range over the past three generations (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). It is therefore tentatively suspected that this rate of cover loss may have led to a decline of between 1-19% in the species' population size over the same time frame, with a best estimate of reduction being 11-14%.
Trend justification
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H. hartlaubi is found in West Africa, from southern Sierra Leone and southern Guinea, east to southern Cameroon and south-western Central African Republic, and south to Gabon and northern Congo including Togo, Liberia, Côte d'Ivoire, Nigeria, Equatorial Guinea, and Ghana (del Hoyo et al. 2001). Requires c. 20-30 ha/pair, suggesting that it is at least locally common (del Hoyo et al. 2001).
H. hartlaubi is found in tall evergreen and gallery forest, especially where there are high densities of lianas (del Hoyo et al. 2001). Insects are the main part of the diet, foraged from the subcanopy and occasionally recorded following troops of monkeys (Kemp 1995, del Hoyo et al. 2001). Lays aseasonally, mainly in October-December but also February and June (del Hoyo et al. 2001). Secretive and relatively quiet and so may be overlooked (del Hoyo et al. 2001).
32cm. Small, mostly black hornbill with a broad white eyestripe, with a fairly long white-tipped tail and black bill with a red tip. Upperparts with a slight green gloss. Similar spp. T. granti is similar but has white tips to the wing coverts and tertials, and more red on the bill, including the casque. Voice. A series of rather soft "kwu-wu.." notes that build to a louder climax, but generally rather silent.
Text account compilers
Rutherford, C.A.
Contributors
Dowsett-Lemaire, F., Lindsell, J. & Rainey, H.
Recommended citation
BirdLife International (2024) Species factsheet: Western Dwarf Hornbill Horizocerus hartlaubi. Downloaded from
https://datazone.birdlife.org/species/factsheet/western-dwarf-hornbill-horizocerus-hartlaubi on 22/12/2024.
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 22/12/2024.