Turdus helleri

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Bibliography

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PASSERIFORMES	TURDIDAE

Scientific Name:

Turdus helleri

Species Authority:

(Mearns, 1913)

Common Name/s:

English

–

Taita Thrush

Assessment Information [top]

Red List Category & Criteria:

Critically Endangered B2ab(i,ii,iii,iv,v) ver 3.1

Year Published:

2009

Assessor/s:

BirdLife International

Reviewer/s:

Symes, A., Butchart, S., Bird, J.

Contributor/s:

Githiru, M., Bennun, L., Lens, L.

Justification:
This species is considered Critically Endangered because it has a tiny occupied range of c.3.5 km², within which its montane forest habitat has been severely fragmented and continues to decline in both extent and quality.

History:

2008	–	Critically Endangered
2004	–	Critically Endangered
2000	–	Critically Endangered
1996	–	Critically Endangered
1994	–	Critically Endangered

Geographic Range [top]

Range Description:	Turdus helleri is confined to four tiny forest patches in the Taita Hills, southern Kenya: Mbololo (c.200 ha), Ngangao (c.92 ha), Chawia (c.50 ha) and Yale (2 ha)^2,3,4,8. Although there have been reported sightings at Mt Kasigau, 50 km south-east of the Taita Hills, survey work in 1998 did not record the species there^1,3. Research in 1997 indicated a total population of c.1,350 birds, with c.1,060 in Mbololo, 250 in Ngangao and 38 in Chawia^8,10,12, although the effective population size is likely to be lower owing to a male-biased sex ratio. In 2009 surveys confirmed continued presence of the species in Mbololo and Ngangao fragments¹³.
Countries:	Native: Kenya
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Waiyaki and Samba (2000)
Population Trend:	Decreasing

Population:

Waiyaki and Samba (2000)

Population Trend:

Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	It is confined to montane cloud-forest⁸, not venturing into secondary growth, scrub or cultivated areas⁹, although the areas where it occurs have been heavily logged in the past³. Despite much research, very few inter-fragment movements have been recorded⁸. It prefers well-shaded areas with a dense understorey, high litter-cover and little or no herbaceous cover⁸, and consequently is found at greater density in Mbolobo, the least disturbed forest area, and is rarest in Chawia, which has a more open canopy and a very shrubby understorey^3,8,10. It rarely ascends more than 2 m above ground⁹. The diet is predominantly fruit³. It is monogamous and terrestrial, with overlapping home ranges⁸ and breeding between January and July. The clutch-size is 1-3⁷. Orange Ground-thrush Zoothera gurneyi often occurs in exactly the same areas as T. helleri³.
Systems:	Terrestrial

Habitat and Ecology:

It is confined to montane cloud-forest⁸, not venturing into secondary growth, scrub or cultivated areas⁹, although the areas where it occurs have been heavily logged in the past³. Despite much research, very few inter-fragment movements have been recorded⁸. It prefers well-shaded areas with a dense understorey, high litter-cover and little or no herbaceous cover⁸, and consequently is found at greater density in Mbolobo, the least disturbed forest area, and is rarest in Chawia, which has a more open canopy and a very shrubby understorey^3,8,10. It rarely ascends more than 2 m above ground⁹. The diet is predominantly fruit³. It is monogamous and terrestrial, with overlapping home ranges⁸ and breeding between January and July. The clutch-size is 1-3⁷. Orange Ground-thrush Zoothera gurneyi often occurs in exactly the same areas as T. helleri³.

Systems:

Terrestrial

Threats [top]

Major Threat(s):	Most indigenous forest has been cleared in the Taita Hills for cultivation or reforestation with non-native timber, and the remaining tiny area is under serious threat from both clearance and degradation^2,4,6, although habitat quality in the largest two fragments remains good^8,14. A highly male-biased sex ratio in Chawia (only 10% of birds were female) might have significant negative consequences for the subpopulation's long-term survival^5,8,10. The species's reproductive rate may thus be lower than expected⁵. Where habitat disturbance leads to deteriorations in body condition, the long-term survival of sub-populations may be put at risk¹¹.

Major Threat(s):

Most indigenous forest has been cleared in the Taita Hills for cultivation or reforestation with non-native timber, and the remaining tiny area is under serious threat from both clearance and degradation^2,4,6, although habitat quality in the largest two fragments remains good^8,14. A highly male-biased sex ratio in Chawia (only 10% of birds were female) might have significant negative consequences for the subpopulation's long-term survival^5,8,10. The species's reproductive rate may thus be lower than expected⁵. Where habitat disturbance leads to deteriorations in body condition, the long-term survival of sub-populations may be put at risk¹¹.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway The Forest Department is now safeguarding the remaining forest fragments of the Taita Hills, which have been designated as an IBA. At present, efforts are being undertaken (ban of cattle grazing, enrichment planting with seedlings) to restore indigenous forest fragment Chawia; while it remains to be seen what affect this has on the the thrush population, unringed juveniles have been seen. An ongoing collaborative research project includes a large ornithological component, which aims to provide the necessary ecological data to plan conservation policies for this and other endemic species in the area. As part of the BirdLife Preventing Extinctions programme for this species and Taita Apalis, Species Guardian Mwangi Githiru has begun to implement the following actions: 1. Tree nurseries are being established by local community-led Environmental Committees. Indigenous trees will be used to restore degraded habitat and enhance the connectivity of scattered forest fragments, whilst on adjacent agricultural land fast-growing non-native species will be planted to provide a buffer zone. 2. Income-generating activities, including bee-keeping and butterfly-rearing have been initiated and farmers have been educated in environmentally responsible agriculture practices. 3. In order to secure the long-term survival of the Chawia population a translocation project is being developed. 4. Nature Kenya has initiated the development of local capacity through catalyzing the formation of a Site Support Group (SSG) with the aim of enabling local people to constructively engage in conservation of the IBA¹³. Conservation Actions Proposed Continue to remove non-native trees from within indigenous forest³, and continue to reforest cleared areas with native trees^2,3. Further develop sustainable forest-use schemes, based on ecotourism and harvesting forest products^2,3 and outreach programmes to local communities^2,3,13. Strengthen the population at Chawia through carefully managed translocations¹³.

Conservation Actions:

Conservation Actions Underway
The Forest Department is now safeguarding the remaining forest fragments of the Taita Hills, which have been designated as an IBA. At present, efforts are being undertaken (ban of cattle grazing, enrichment planting with seedlings) to restore indigenous forest fragment Chawia; while it remains to be seen what affect this has on the the thrush population, unringed juveniles have been seen. An ongoing collaborative research project includes a large ornithological component, which aims to provide the necessary ecological data to plan conservation policies for this and other endemic species in the area. As part of the BirdLife Preventing Extinctions programme for this species and Taita Apalis, Species Guardian Mwangi Githiru has begun to implement the following actions: 1. Tree nurseries are being established by local community-led Environmental Committees. Indigenous trees will be used to restore degraded habitat and enhance the connectivity of scattered forest fragments, whilst on adjacent agricultural land fast-growing non-native species will be planted to provide a buffer zone. 2. Income-generating activities, including bee-keeping and butterfly-rearing have been initiated and farmers have been educated in environmentally responsible agriculture practices. 3. In order to secure the long-term survival of the Chawia population a translocation project is being developed. 4. Nature Kenya has initiated the development of local capacity through catalyzing the formation of a Site Support Group (SSG) with the aim of enabling local people to constructively engage in conservation of the IBA¹³.

Conservation Actions Proposed
Continue to remove non-native trees from within indigenous forest³, and continue to reforest cleared areas with native trees^2,3. Further develop sustainable forest-use schemes, based on ecotourism and harvesting forest products^2,3 and outreach programmes to local communities^2,3,13. Strengthen the population at Chawia through carefully managed translocations¹³.

Bibliography [top]

	Barnes, J.; Barnes, R.; Burston, P.; Githiru, M.; Leckie, J.; Mulwa, R.; Pilgrim, J. 1999. Project Kasigau '98. Brooks, T. 1997. Threatened birds of Kenya 9: Taita Thrush. Kenya Birds 5(2): 102-104. Brooks, T.; Lens, L.; Barnes, J.; Barnes, R.; Kageche Kihuria, J.; Wilder, C. 1998. The conservation status of the forest birds of the Taita Hills, Kenya. Bird Conservation International 8: 119-139. Collar, N. J.; Stuart, S. N. 1985. Threatened birds of Africa and related islands: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, and International Union for Conservation of Nature and Natural Resources, Cambridge, U.K. Galbusera, P.; Lens, L.; Schenck, T.; Waiyaki, E.; Matthysen, E. 2000. Genetic variability and gene flow in the globally, critically-endangered Taita Thrush. Conservation Genetics 1: 45-55. Lens, L.; Bennun, L. A.; Duchateau, L. 2001. Landscape variables affect the density of Sharpe's Longclaw Macronyx sharpei, a montane grassland specialist. Ibis 143: 674-676. Lens, L.; Galbusera, P.; Brooks, T.; Waiyaki, E.; Schenck, T. 1998. Highly skewed sex ratios in the critically endangered Taita thrush as revealed by CHD genes. Biodiversity and Conservation 7(7): 869-873. Mulwa, R. 1998. An ornithological survey of Mt Kasigau Forest with particular emphasis on Taita White-eye Zosterops poliogaster silvanus in Taita Tareta District, Kenya. In: Bytebier, B. (ed.), Taita Hills Biodiversity Project Annual Report Second Year (November 1997--October 1998), pp. Appendix 10.2.9. National Museums of Kenya, Nairobi. Rogers, P. C.; O'Connell, B.; Mwang'ombe, J.; Madoffe, S.; Hertel, G. 2008. Forest health monitoring in the Ngangao Forest, Taita Hills, Kenya: a five year assessment of change. Journal of East African Natural History 97(1): 3-17. Urban, E. K.; Fry, C. H.; Keith, S. 1997. The birds of Africa vol. V. Academic Press, London. Waiyaki, E.; Samba, D. 2000. Status and ecology of the critically endangered Taita Thrush Turdus helleri. Waiyaki, E.; Samba, D.; Lens, L. 2001. Status and ecology of the critically endangered Taita Thrush, Turdus helleri. Ostrich: 198. Zimmerman, D. A.; Turner, D. A.; Pearson, D. J. 1996. Birds of Kenya and northern Tanzania. Helm, London.

Barnes, J.; Barnes, R.; Burston, P.; Githiru, M.; Leckie, J.; Mulwa, R.; Pilgrim, J. 1999. Project Kasigau '98.

Brooks, T. 1997. Threatened birds of Kenya 9: Taita Thrush. Kenya Birds 5(2): 102-104.

Brooks, T.; Lens, L.; Barnes, J.; Barnes, R.; Kageche Kihuria, J.; Wilder, C. 1998. The conservation status of the forest birds of the Taita Hills, Kenya. Bird Conservation International 8: 119-139.

Collar, N. J.; Stuart, S. N. 1985. Threatened birds of Africa and related islands: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, and International Union for Conservation of Nature and Natural Resources, Cambridge, U.K.

Galbusera, P.; Lens, L.; Schenck, T.; Waiyaki, E.; Matthysen, E. 2000. Genetic variability and gene flow in the globally, critically-endangered Taita Thrush. Conservation Genetics 1: 45-55.

Lens, L.; Bennun, L. A.; Duchateau, L. 2001. Landscape variables affect the density of Sharpe's Longclaw Macronyx sharpei, a montane grassland specialist. Ibis 143: 674-676.

Lens, L.; Galbusera, P.; Brooks, T.; Waiyaki, E.; Schenck, T. 1998. Highly skewed sex ratios in the critically endangered Taita thrush as revealed by CHD genes. Biodiversity and Conservation 7(7): 869-873.

Mulwa, R. 1998. An ornithological survey of Mt Kasigau Forest with particular emphasis on Taita White-eye Zosterops poliogaster silvanus in Taita Tareta District, Kenya. In: Bytebier, B. (ed.), Taita Hills Biodiversity Project Annual Report Second Year (November 1997--October 1998), pp. Appendix 10.2.9. National Museums of Kenya, Nairobi.

Rogers, P. C.; O'Connell, B.; Mwang'ombe, J.; Madoffe, S.; Hertel, G. 2008. Forest health monitoring in the Ngangao Forest, Taita Hills, Kenya: a five year assessment of change. Journal of East African Natural History 97(1): 3-17.

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

Waiyaki, E.; Samba, D. 2000. Status and ecology of the critically endangered Taita Thrush Turdus helleri.

Waiyaki, E.; Samba, D.; Lens, L. 2001. Status and ecology of the critically endangered Taita Thrush, Turdus helleri. Ostrich: 198.

Zimmerman, D. A.; Turner, D. A.; Pearson, D. J. 1996. Birds of Kenya and northern Tanzania. Helm, London.

Citation:	BirdLife International 2009. Turdus helleri. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 22 May 2012.
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