White-necked Rockfowl (Picathartes gymnocephalus) | Text

White-necked Rockfowl Picathartes gymnocephalus

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Justification

Justification of Red List category
This species now has a highly fragmented distribution. The majority of breeding colonies are extremely small and isolated, and many are close to the minimum for long-term viability. Forest throughout its range is disappearing rapidly, leading to further fragmentation and rapid decline of remaining populations. It is therefore classified as Vulnerable. Its long-term future will depend on the continued existence and proper management of the forest reserves and other protected areas in which it occurs.

Population justification
The total population is estimated at fewer than 10,000 individuals. This figure is supported by estimates for range states provided by various sources. It is placed in the band 2,500-9,999 mature individuals, equating to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals.

Trend justification
The species's population is suspected to be declining rapidly, in line with forest clearance and degradation across its range.

Distribution and population

Picathartes gymnocephalus is known from Guinea (six sites; population probably declining), Sierra Leone (18 sites), Liberia (six sites; population probably declining; most records in northern highlands), Côte d'Ivoire (six sites; population likely to be declining as forest is being cleared and logged in areas which have not been surveyed), and Ghana (many records into the 1960s, then none confirmed until 2003, and now known from several sites; population has probably rapidly declined in last 30 years) (Gatter 1997, H. S. Thompson in litt. 1999, Marks et al. 2004, Thompson et al. 2004, H. Rainey in litt. 2007, A. Asamoah in litt. 2012). It was thought to be extinct in Ghana until one individual was trapped at Subim Forest Reserve (Anon. 2006) in the Brong-Ahafo Region. Follow-up surveys in the Subim and adjoining Ayum and Bonsam Bepo forest reserves located 13 active nests and two individuals (Anon. 2006). Further investigations have since located other sites for this species, including seven major nesting areas within the high forest zone, with possibly over 100 nests at 33 sites (Dowsett-Lemaire and Dowsett 2009, Asamoah 2011, Dowsett-Lemaire and Dowsett 2014). In Sierra Leone, numbers are estimated at c.1,400, with populations in forest reserves close to the minimum for long-term viability, and surveys of the Western Area Peninsula Forest indicating a decline of 20% in the number of nests between 1997-2007 (Anon. 2008), although the population in Gola Forest may be stable (Monticelli et al. 2012). In Liberia, the minimum population is estimated at 1,000 pairs (Gatter 1997). The global population in the Upper Guinea forest is almost certainly far fewer than 10,000 mature individuals, and this is supported by estimates for range states provided by various sources (Thompson et al. 2004).

Ecology

It is found in lowland primary and secondary forest, forest clearings, and gallery forest mainly in rocky, hilly terrain (up to 800 m on Mt Nimba) (Gatter 1997, Thompson 1997, 1998, L. D. C. Fishpool in litt. 1999), but has survived at highly degraded sites and close to urban centres (Salewski et al. 2000, Thompson and Fotso 2000), perhaps indicating a fairly high tolerance of disturbance (Thompson et al. 2004). The species is found in the proximity of flowing streams and rivers, where wet mud may be gathered for nest construction (Thompson et al. 2004). A study of the ecology and distribution of the species in Ghana indicated that it uses fresh earthworm mounds to construct its nest (Asamoah 2011). It is known from montane forests in Sierra Leone and Liberia (Thompson et al. 2004). It feeds mainly on invertebrates, usually singly and largely within one metre of the forest floor (Thompson and Fotso 1995). Individuals frequently follow army ant columns to capture flushed prey (Thompson 1998, Thompson et al. 2004). They take beetles, termites, ants and grasshoppers, as well as earthworms, spiders and vertebrates such as frogs and lizards (Thompson et al. 2004). There is some evidence that vertebrates in the diet during the breeding season may be fed largely to nestlings (Thompson 1997). It breeds in colonies of up to 40 pairs (although the majority consist of only 2-5, and many nests stand alone [Thompson 2004b]), on rock-faces, cliffs, cave roofs and walls and infrequently in large, fallen hollow trees (Thompson and Fotso 1995, Atkinson et al. 1996b, Gatter 1997, Thompson 1998); rocky sites are the most common, however. In lowland forest breeding follows rainfall and maybe be once or twice yearly as a result (Thompson and Fotso 2000). The species appears to be monogamous (Thompson et al. 2004). The nest is a cup-shaped mud construction in which dried leaves, fibres and twigs are embedded (Thompson 2004b). In Sierra Leone, egg-laying occurs from early June until late December, and chicks occupy nests from August to January (Thompson 2004a, b) Egg-laying in Ghana starts from early March and continues through to mid-December (Asamoah 2011). Clutch size is one or two (Thompson 1997). In Sierra Leone, the most common clutch size was found to be two, with incubation lasting for 17-23 days and the fledging period lasting for 23-29 days (Thompson 2004b). Nest mortality was caused by predation and infanticide by other adults, and breeding success was only 0.44 chicks fledged per pair. Natural nest predators probably include cobras Naja sp., Monitor Lizards Varanus niloticus, Forest Sun Squirrels Heliosciurus, raptors and colobine monkeys Procolobus sp.. The low breeding success of the populations studied in Sierra Leone suggest that they are in decline, that is unless adult survival exceeds 90% and the species is very long-lived (Thompson 2004b).

Threats

The species is threatened throughout its range primarily by commercial logging for timber. Most sites identified in Ghana are in productive forest reserves, where commercial logging takes place periodically (Owusu and Asamoah 2008, Asamoah 2011). In Ghana, the species is also threatened by bush-burning and conversion of degraded forests to plantations (Asamoah 2011). Many nesting areas in Ghana, especially those outside protected areas, have been destroyed through clearance for agriculture and bush-burning (Asamoah 2011). In Ghana, it may also be threatened by mining for gold, manganese and bauxite (Holbech 1996, Asamoah 2011). In Sierra Leone, abandonment of colonies has been associated with habitat degradation (Thompson 1997), and low breeding success at some sites is associated with human disturbance (Thompson 1998). Small populations near urban centres in Sierra Leone are severely threatened by conversion to farmland (Thompson and Fotso 2000). Logging and other forms of forest clearance may threaten presently unknown sites for the species, particularly in the mountains of western Côte d'Ivoire and south-eastern Guinea (H. Rainey in litt. 2007). Nest-predation and competition from conspecifics, e.g. for limited nest-sites, (Thompson 1997) are other factors. Some opportunistic trapping with noose traps and wire snares may occur e.g. for zoo-collecting (R. Fotso per M. Gartshore in litt. 1999, H. S. Thompson in litt. 2007). In Sierra Leone, children have recently been observed taking eggs (Thompson 2004b).

Conservation actions

Conservation Actions Underway
CITES Appendix I. Following the rediscovery of the species in Ghana by museum collectors from the U.S.A. in March 2003 (Marks et al. 2004, Anon. 2006), the Ghana Wildlife Society has begun to determine the status of the species in the country (R. Dowsett in litt. 2005, Anon. 2006, A. Asamoah in litt. 2007) and efforts are underway to protect the species in the reserves where it has been located (Marks et al. 2004). Some important nesting sites have been identified, and monitoring of the population and breeding activity at an active nesting area in Adansi South district is being carried out (A. Asamoah in litt. 2007), with community involvement and education programmes initiated (Oxford Miller 2013). A Picathartes working group has recently been formed, to promote research and conservation action (H. S. Thompson in litt. 1999). An International Action Plan for the species was published in 2004 following an international stakeholder workshop, with the aim to stabalise or increase its populations at its strongholds in all range states within five years (Thompson et al. 2004). A one-year programme to initiate population monitoring, recruitment and training of wardens (resulting in the establishment of a wardening system around all known colonies) and awareness-raising activities has been carried out in the Western Area Peninsula Forest, Sierra Leone (H. Thompson in litt. 2007, Anon. 2008). The species is protected by national law in some states (e.g. Ghana, Sierra Leone, Cameroon), but enforcement is minimal (Thompson and Fotso 2000, Thompson 2004b, R. Fotso and E. Owusu per Thompson 2004b). Although a high proportion of the populations in Sierra Leone, Guinea, Ghana and Cote d'Ivoire occur in nominally protected areas, the population of Liberia occurs almost wholly in unprotected habitat (Thompson et al. 2004). An ongoing conservation programme has been working towards the upgrading of Gola Forest to a National Park (H. Thompson in litt. 2007), which has now been realized. A memorandum of understanding has been signed by the Liberian government to significantly increase the size of the country's protected area system (Thompson et al. 2004). The species is protected by local religious beliefs in some areas (Thompson and Fotso 1995).

Conservation Actions Proposed
Undertake surveys to estimate population sizes and distribution particularly in mountains of western Cote d'Ivoire, which may have many small colonies in remaining unlogged forest reserves (Holbech 1996, Thompson et al. 2004, H. Rainey in litt. 2007). Conduct long-term monitoring of breeding success at strongholds and study the factors affecting it (Thompson 1997, Thompson et al. 2004). Improve breeding success at selected strongholds by mitigating against limiting factors (Thompson et al. 2004). Monitor and assess the impact of human-related activities on the species and its sites (Thompson et al. 2004). Assess the legal status of human activities threatening sites and enforce the law where appropriate (Thompson et al. 2004). Develop and implement management plans for the species's strongholds (Thompson et al. 2004). Determine the area around the species's sites required to ensure survival and lobby for legal protection (Thompson et al. 2004). Employ wardens at key sites (Thompson et al. 2004). Incorporate the species's International Action Plan into national conservation strategies (Thompson et al. 2004). Where feasible, protect large breeding colonies through agreements and collaboration with local people. Incorporate the species into management plans and exclude logging from the immediate vicinity of active nesting sites (Asamoah 2011). Conduct genetic studies using samples from different subpopulations to assess the effective population size and the degree of inbreeding. Raise awareness of the species amongst all stakeholders, especially local communities (Thompson et al. 2004). Expand the potential for ecotourism (Thompson and Fotso 2000), taking care to minimise disturbance at the most easily accessible sites (Salewski et al. 2000). Develop sustainable income-generating activities near strongholds (Thompson et al. 2004).

Identification

Large, unusual bird with brightly coloured, naked head. Bright, chrome-yellow and black head is diagnostic. Neck and underparts gleaming white with dark, bluish-grey upperparts and tail. Voice Breathy shhhissss and other soft tok calls, but usually silent.

Acknowledgements

Text account compilers
Symes, A., Shutes, S., Ekstrom, J., Westrip, J., Taylor, J.

Contributors
Asamoah, A., Gartshore, M., Fotso, R., Rainey, H., Dowsett, R.J., Thompson, H.S., Fishpool, L.

Recommended citation
BirdLife International (2024) Species factsheet: White-necked Rockfowl Picathartes gymnocephalus. Downloaded from https://datazone.birdlife.org/species/factsheet/white-necked-rockfowl-picathartes-gymnocephalus on 23/12/2024.
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 23/12/2024.