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 <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). 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 (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The global population size has not been quantified, but the species is reported to be locally common (del Hoyo et al. 2001).
Although it has been claimed to be restricted to pristine forest (del Hoyo et al. 2001), it is reportedly more common in open-canopy, logged forest than in mature, closed-canopy forest (F. Dowsett-Lemaire in litt. 2013) and is not thought to be threatened by hunting (H. Rainey in litt. 2013). Nevertheless, it is suspected to be undergoing some declines overall owing to ongoing habitat destruction and fragmentation.
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
Butchart, S., Ekstrom, J., Symes, A. & Taylor, J.
Dowsett-Lemaire, F., Lindsell, J. & Rainey, H.
BirdLife International (2021) Species factsheet: Horizocerus hartlaubi. Downloaded from http://www.birdlife.org on 28/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 28/10/2021.