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Crossley's Ground-thrush Zoothera crossleyi

Justification
This species is classed as Near Threatened because it is suspected to undergo a moderately rapid population decline over the next three generations owing to habitat loss driven by the expansion of small-holder cultivation and large-scale plantations.

Taxonomic source(s)
Dowsett, R. J.; Forbes-Watson, A. D. 1993. Checklist of birds of the Afrotropical and Malagasy regions. Tauraco Press, Li
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Distribution and population
Zoothera crossleyi is found in south-eastern Nigeria (on the Obudu and Mambilla Plateaux and Gotel Mountains), Cameroon (from Mt Cameroon and the Rumpi Hills in the south-west to Mt Tchabal Mbabo on the Adamawa Plateau [Dowsett-Lemaire and Dowsett 1999]), southern Congo and north-eastern Democratic Republic of Congo (DRC) (Urban et al. 1997). In Nigeria, it was found to be common at Chappal Waddi in the Gotel Mountains but less numerous elsewhere in 1988 (Ash et al. 1989). In Cameroon, it was quite common to very common in the northern Bakossi Mountains in 1998 and on Mt Nlonako in 1999 (Dowsett-Lemaire and Dowsett 1998, 1999), and was also discovered on the southern slopes of Mt Manenguba in 1999 (Dowsett-Lemaire and Dowsett 1999) and seen again there in 2000 (Dowsett-Lemaire and Dowsett 2000).

Population justification
The global population size has not been quantified, but the species is described as rare to locally fairly common (del Hoyo et al. 2005).

Trend justification
It is suspected that the population will undergo a moderately rapid decline over the next three generations owing to habitat destruction and fragmentation for small-scale cultivation and large-scale oil-palm plantations (del Hoyo et al. 2005, F. Dowsett-Lemaire in litt. 2013).

Ecology
It inhabits mid-altitude forest, at 1,000-2,300 in Cameroon, 500-600 m in Congo and 960-1,850 m in DRC (del Hoyo et al. 2005), preferring wetter parts of primary forest, particularly ravines (Urban et al. 1997). It feeds mainly on insects and also takes seeds, foraging on the ground in deep cover (del Hoyo et al. 2005). Breeding probably occurs during the rainy season. In Cameroon, the species may undertake altitudinal migrations, but the extent of this is unknown (del Hoyo et al. 2005).

Threats
The species is susceptible to forest loss within its increasingly fragmented range. In DRC, the species's habitat is being encroached by banana plantations (del Hoyo et al. 2005). The montane and semi-montane forests of western Cameroon are under increasing pressure from clearance for gardens (e.g. Mt Kupe) and, in recent years, for the expansion of large-scale oil-palm plantations, which has led to the encroachment of the Bakossi block of forest (F. Dowsett-Lemaire in litt. 2013).

Conservation Actions Underway
No targeted conservation action is known for this species. Conservation Actions Proposed
Carry out surveys to assess the total population size. Monitor population trends through regular surveys. Monitor rates of habitat loss and degradation. Protect suitable habitat for the species.

References
Ash, J. S.; Dowsett, R. J.; Dowsett-Lemaire, F. 1989. New ornithological distribution records from eastern Nigeria. In: Dowsett, R.J. (ed.), A preliminary natural history survey of Mambilla Plateau and some lowland forests of eastern Nigeria, pp. 13-27. Tauraco Press, Ely, U.K.

del Hoyo, J.; Elliott, A.; Christie, D. 2005. Handbook of the Birds of the World, vol. 10: Cuckoo-shrikes to Thrushes. Lynx Edicions, Barcelona, Spain.

Dowsett-Lemaire, F.; Dowsett, R. J. 1998. Zoological survey of small mammals, birds and frogs in the Bakossi and Kupe Mountains, Cameroon.

Dowsett-Lemaire, F.; Dowsett, R. J. 1999. Survey of birds and amphibians on Mt Manenguba, Mt Nlonako, north Bakossi and around Kupe in 1988-99.

Dowsett-Lemaire, F.; Dowsett, R. J. 2000. Further biological surveys of Manenguba and Central Bakossi in March 2000, and an evaluation of the conservation importance of Manenguba, Bakossi, Kupe and Nlonako Mts, with special reference to birds.

IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.1). Available at: http://www.iucnredlist.org. (Accessed: 19 June 2012).

Urban, E. K.; Fry, C. H.; Keith, S. 1997. The birds of Africa vol. V. Academic Press, London.

Further web sources of information
Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
O'Brien, A., Robertson, P., Symes, A. & Taylor, J.

Contributors
Dowsett-Lemaire, F.

Recommended citation
BirdLife International (2014) Species factsheet: Zoothera crossleyi. Downloaded from http://www.birdlife.org on 24/09/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 24/09/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Near Threatened
Family Turdidae (Thrushes)
Species name author (Sharpe, 1871)
Population size Unknown mature individuals
Population trend Decreasing
Distribution size (breeding/resident) -
Country endemic? No
Links to further information
- Additional Information on this species
- Projected distributions under climate change