Justification of Red List Category
This species is listed as Vulnerable because it is suspected to be undergoing a rapid population decline owing to the impacts of habitat destruction and degradation, and hunting pressure.
The population size of this species has not been quantified.
The population is suspected to be in rapid decline owing to the destruction and degradation of its habitats and unsustainable hunting pressure.
Bycanistes cylindricus is restricted to the Upper Guinea forests of West Africa, where it is found in southern Guinea, Sierra Leone (including Loma Mountains, Western Area Peninsula Forest, Kangri Hills and Gola Forest [Okoni-Williams 2001]), Liberia, southern Côte d'Ivoire (where it remains abundant in Taï National Park and periphery habitat [Gartshore et al. 1995, H. Rainey in litt. 2007]), south-west Ghana (where recently observed only once during surveys of Draw River, Boi-Tano and Krokasua Forest Reserves [H. Rainey in litt. 2007]) and Togo (Kemp 1995; although this single record may be best considered unconfirmed [F. Dowsett-Lemaire in litt. 2012]). Its local status varies from uncommon to common (Nash 1990a, Gartshore et al. 1995, Gatter 1997). Recent observations suggest that the species is in rapid decline. It has been extirpated from Bia National Park (NP) in Ghana, where there have been no records since 1991 (Dowsett-Lemaire and Dowsett 2011). Several hunters interviewed by Dowsett-Lemaire and Dowsett (2009) in Ghana have said that B. cylindricus has become rare or difficult to find and the species may now be extinct at Fure Headwaters. It may also have disappeared from Opro River Forest Reserve (FR) (Dowsett-Lemaire and Dowsett 2010). Surveys at three forest reserves in Ghana (Draw River, Bio-Tano and Krokosua) in 2003 suggested that hornbills were in decline owing to habitat fragmentation and hunting (H. Rainey in litt. 2011). Observations of hornbill abundance in the forests of West Africa should be interpreted with regard to these species' movements, probably related to fruit abundance (e.g. H. Rainey in litt. 2011).
It is a species of primary and mature secondary forest (Thiollay 1985a). It has been found in very disturbed forest in Mt Peko National Park, Côte d'Ivoire (H. Rainey in litt. 1999), and also around forest edges and farmbrush in Sierra Leone (E. Klop in litt. 2016) but generally prefers undisturbed forest (Holbech 1992, 1996). It is also found in plantations, and has been found to be more common in these sites than other hornbill species (Gartshore et al. 1995), but it is not known whether these represent viable breeding populations. In the Gola Forest, Sierra Leone, it has a similar distribution to that of Black-casqued Hornbill Ceratogymna atrata, and so these species may have similar habitat preferences (E. Klop in litt. 2016). As with other large hornbills, it is probably dependent on the presence of large emergent trees and dead standing trees for nest sites (Gartshore et al. 1995). It forages on fruit in the canopy and will also take insects on the wing (Fry et al. 1988). Local populations in Cameroon fluctuate 12-fold and in synchrony, suggesting regional movements to track fruit availability (del Hoyo et al. 2001). It is described as sedentary in Gabon and nomadic during the non-breeding season in Liberia and Uganda. In Liberia, egg-laying probably takes place in September-November, but this may occur in January-April, June-August or October-December elsewhere. It nests in natural tree cavities 20-25 m from the ground. The species appears not to breed every year (del Hoyo et al. 2001).
The species is threatened by the destruction and fragmentation of forest throughout its range (H. Rainey in litt. 1999, del Hoyo et al. 2001). This species is often the first large hornbill to disappear following selective logging (Gatter 1997). Although hornbills can travel many kilometres in a single day in search of fruiting trees, the increasing fragmentation of the Upper Guinea forest is likely to have affected populations, particularly as fragmentation is on-going and large fragments are becoming increasingly isolated (H. Rainey in litt. 2011). Forest is being lost in some protected areas, for example most forest has now been lost from Déré Foret Classée in Guinea (H. Rainey in litt. 2012). Deforestation in the region is driven by logging for timber, agricultural expansion and development, with some of the highest pressures on forest habitats occurring in Liberia (H. Rainey in litt. 2011), where there are plans to convert large areas of primary forest to oil-palm plantations (F. Dowsett-Lemaire in litt. 2012). Much forest in Opro River FR, Ghana, has been replaced with teak plantations, whilst forest at Amama Shelterbelt FR has been cleared for gardens and plantations (F. Dowsett-Lemaire in litt. 2012). Hunting is a significant threat both within and outside protected areas (H. Rainey in litt. 1999, 2011; F. Dowsett-Lemaire in litt. 2012). Hunting pressure has led to its extirpation from Bia National Park (NP), where there have been no records since 1991 (Dowsett-Lemaire and Dowsett 2009, 2011), although it persists at a number of other sites, including small numbers at Atewa Range FR and Tano Ofin FR, despite high hunting pressure at these locations (Dowsett-Lemaire and Dowsett 2009).
Conservation Actions Underway
It occurs in a number of protected areas, including Maraoué National Park (del Hoyo et al. 2001), Taï National Park (Gartshore et al. 1995, del Hoyo et al. 2001) and Gola Forest (Okoni-Williams 2001).
60-70 cm. Large hornbill with pale yellow bill and casque, black head (with reddish tinged cheeks in subspecies cylindricus), crest, back and upper underparts, contrasting with mostly white remiges, and lower underparts; tail white with black band. Female has smaller, back bill and casque.
Text account compilers
Shutes, S., O'Brien, A., Starkey, M., Taylor, J., Robertson, P., Westrip, J.
Klop, E., Lindsell, J., Rainey, H., Dowsett-Lemaire, F., Hall, P.
BirdLife International (2020) Species factsheet: Bycanistes cylindricus. Downloaded from http://www.birdlife.org on 30/11/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 30/11/2020.