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Thyolo Alethe Chamaetylas choloensis
BirdLife is reviewing the status of this species for the 2017 Red List.
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Justification

Justification of Red List Category
Most of this species's locations within its very small range are under severe pressure from deforestation and forest degradation. These threats are increasing, deforestation is accelerating and much of its remaining habitat is likely to be cleared in the near future. This is likely have led to an ongoing rapid decline in the species's very small and severely fragmented population. The species is therefore listed as Endangered. Further data from its Mozambique range may lead to its downlisting if substantial populations are confirmed in areas of forest which are not under significant immediate threat and the Extent of Occurrence is greater than currently thought.

Population justification
The world population was thought to be in the range of c.2,500-5,000 mature individuals, however in 2005 the species was discovered on Mt Mabu in Mozambique, where the population is conservatively suspected to number c.2000 individuals, and there are other areas of this country that could hold the species. Thus on the basis that further exploration is required before a reliable estimate of the total population can be made, the population is placed in the range bracket for 2,500-9,999 individuals. This equates to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.

Trend justification
The population is suspected to be declining very rapidly in Malawi in line with the extensive clearance and degradation of highland forests there, and to a lesser degree in Mozambique, with a substantial proportion of the known population occurring on Mt Mabu where there is currently relatively low pressure on the forest. Overall, the rate of decline over 20 years (three generations) is suspected to have been rapid. Further substantial populations may occur in intact forests in unsurveyed areas of Mozambique (Spottiswoode et al. 2008), which, if found to be the case, would have a bearing on the overall proportion of the population that is decreasing and thus the overall rate of decline.

Distribution and population

Alethe choloensis is known from 16 areas of forest, 13 of them in south-eastern Malawi (east of the Shire river), plus four in adjacent Mozambique (Mts Namuli [Keith et al. 1992], Chiperone [Keith et al. 1992, Spottiswoode et al. 2008], Mabu [Spottiswoode et al. 2008], and Inago [Bayliss et al. 2010, Fishpool and Bayliss 2010]). The species probably occurs on mountains between Mts Namuli and Mabu (F. Dowsett-Lemaire in litt. 2008). Its world population was thought to be in the range of c.2,500-5,000 mature individuals. However, in 2005, the species was discovered on Mt Mabu, where the population is described as common and conservatively suspected to number c.2,000 individuals, or possibly 1,000-1,500 pairs (Spottiswoode et al. 2008, Dowsett-Lemaire and Dowsett 2009, Bayliss et al. 2014). In Malawi, there were c.1,500 pairs in 1983, mostly on Mt Mulanje (1,000 pairs) and Mt Thyolo (200 pairs) (Dowsett-Lemaire 1989), but the population has almost certainly decreased since then (F. Dowsett-Lemaire in litt. 1997, 2000, P. Kaliba and L. Luhanga in litt. 2003). Recent reports (2003) suggest that the Malawi population is now confined to five areas and that two historical sites (including Thyolo) have been lost to encroachment by agriculturalists (P. Kaliba and L. Luhanga in litt. 2003, Spottiswoode et al. 2008). The most important remaining populations in Malawi are likely to be in the wet forest on Chikala Hill in Liwonde forest reserve, the wet forest on the summit of Mangochi Mountain forest reserve, and in the Ruo and Chisongeli forests on Mt Mulanje (F. Dowsett-Lemaire per Spottiswoode et al. 2008, J. Bayliss in litt. 2016). Although c.1,000 pairs were estimated on Mt Namuli in 1998 (Ryan et al. 1999) these figures may be far too high, and Dowsett-Lemaire (2010) estimated <50 pairs for Namuli, excluding the unexplored plateau south of the Malema River. In November 2007, the species was recorded as reasonably common in Ukalini Forest (Mt Namuli), at c.2 pairs/10 ha (Dowsett-Lemaire 2010). The population in Manho Forest (Mt Namuli) was estimated at 'a few dozen pairs' in 2007 (F. Dowsett-Lemaire in litt. 2008). On Mt Chiperone, the population is conservatively suspected to number c.800 individuals (Spottiswoode et al. 2008), and on Mabu it is common above 1,200 m and may number at least 1,000 pairs (Dowsett-Lemaire 2010). On Mt. Inago the situation is very serious with widespread deforestation; and there are only estimated <50 pairs (J. Bayliss in litt. 2016).

Ecology

It is a terrestrial bird of submontane evergreen forest, and breeds at mid-altitudes (mainly above 1,200 m, but some as low as 950 m on Mabu), but can occur lower in the non-breeding season (March-October) (Dowsett-Lemaire 1989). Its population density is closely tied to the presence of ant-nests. Pairs can persist in forest patches as small as 0.5 ha if there is an ant-nest, but the density is usually much lower (F. Dowsett-Lemaire in litt. 1997, 2000).

Threats

Deforestation at its sites in Malawi is intense; between the 1970s and early 1990s, at least three of its localities were completely cleared, e.g. the 40 km2 Chisongeli Forest (Mt Mulanje) (Dowsett-Lemaire 1989, F. Dowsett-Lemaire in litt. 1997, 2000). Deforestation of Chisongeli Forest had stabilised at c.1,600 m in 2007, with nearly all forest cleared below this altitude, and only c.20 km2 remaining between 1,600 and 2,000 m (F. Dowsett-Lemaire in litt. 2008). During 1995-1996, severe fires destroyed much of its habitat at Lisau (Mt Chiradzulu) as well as parts on Zomba (F. Dowsett-Lemaire in litt. 1997, 2000) which hold the second largest population of this species (J. Haugaard in litt. 2003). Over the period 1999-2003, Thyolo Forest Reserve was completely cleared for subsistence agriculture, reducing forest on the mountain to a single small fragment on private land (Spottiswoode et al. 2008). Soche Mountain has lost 30-40% of its remaining mist-belt forest (J. Haugaard in litt. 2003, P. Kaliba and L. Luhanga in litt. 2003) and forest at Ndirande was completely cleared in the 1990s (F. Dowsett-Lemaire in litt. 2006). During the late 1990s, selective logging started at Mt Namuli, and a road passing close to the summit was being built, which was expected lead to large-scale forest exploitation from the densely-populated lower slopes (V. Parker in litt. 1998), however, this road has since become impassable (J. Timberlake in litt. 2016). In November 2007, it was noted that the extent of mid-altitude forest on the eastern slopes of Mt Namuli was in decline and that suitable habitat for the species was almost gone (F. Dowsett-Lemaire in litt. 2008). The threats on Mt Namuli include fires and encroachment by settlements. Limited encroachment (c.5 ha in November 2007) of Ukalini Forest has taken place, small areas of Manho Forest have been cleared for cultivation, and both Ukalini and Manho Forests are threatened by the extraction of Faurea wentzeliana for the trade in construction material. The gaps left by such extraction are detrimental to the species, as it requires a shaded understorey (F. Dowsett-Lemaire in litt. 2008). Encroachment by subsistence farmers expected to occur on Mt Chiperone in the near future (V. Parker in litt. 1998, J. Timberlake in litt. 2016), although this may slow at higher altitudes because of steep terrain and local spiritual beliefs (Spottiswoode et al. 2008). At Mt Mabu, commercial tea farming was reported to resume on abandoned tea estates at low altitudes, and this could have led to a human population influx (Spottiswoode et al. 2008, Bayliss et al. 2014), however the forest is currently under much less pressure than at Namuli (Dowsett-Lemaire 2010), and tea farming has not yet resumed (J. Timberlake in litt. 2016). There will soon be very little habitat remaining for the species across its range (F. Dowsett-Lemaire in litt. 1997, 2000, J. Haugaard in litt. 2003, P. Kaliba and L. Luhanga in litt. 2003), with the situation at Mt Inago being serious, as forest patches are estimated at <10km (Bayliss et al. 2010, Fishpool and Bayliss 2010).

Conservation actions

Conservation Actions Underway
Several sites in Malawi are Forest Reserves, but in reality this provides negligible protection. Forest on Mt Namuli, Mt Inago and Mt Chiperone is not protected, although efforts were underway in early 2008 to protect some of this habitat (F. Dowsett-Lemaire in litt. 2008).There are some conservation initiatives on Mt Mabu but they are not getting much traction yet (J. Timberlake in litt. 2016). If access to Mt Namuli improves, it is a potential site for ecotourism-based conservation (K. Barnes in litt. 1998), and it may be recognised as some kind of protected area in the future (J. Timberlake in litt. 2016). The main stronghold in Malawi of this near-endemic is undoubtedly Mulanje Mountain, which is now the centre of a major GEF programme which will hopefully ensure the survival of the mist-belt forests circling the mountain (J. Haugaard in litt. 2003).

Conservation Actions Proposed
Initiate a campaign in Malawi of land reform and conservation of water resources through the maintenance of remaining forest reserves (F. Dowsett-Lemaire in litt. 1997, 2000, M. Dyer in litt. 1999). Protect forest on Mt Namuli from logging, including as clearance for spreading agriculture and livestock (Ryan et al. 1999, J. Timberlake in litt. 2016). Continue surveys on Mt Mabu (e.g. Dowsett-Lemaire and Dowsett 2009) and Mt Chiperone and other areas in northern Mozambique, such as Mt Morrumbala and the highlands near Njesi Plateau (Spottiswoode et al. 2008). Conduct surveys to re-assess the species's status on Mt Namuli (F. Dowsett-Lemaire in litt. 2008), and Mt. Inago (Bayliss et al. 2010; Fishpool & Bayliss, 2010). Once initial surveys have been conducted in all potential areas, assess the species's population size across its range. Once a baseline population estimate has been obtained, continue to monitor population trends. Monitor the rate of forest clearance and extent of habitat degradation.

Identification

16 cm. Small, thrush-like bird of forest undergrowth. Warm rusty upperparts. White underparts, with grey wash on sides of face and neck. White tips to outer tail-feathers. Long, flesh-coloured legs and toes. Similar spp. White-chested Alethe A. fuelleborni lacks white tail-spots and does not occur near this species. Voice Soft trrrp alarm call. Soft, melodic song. Hints Hops on leaf-litter. It usually feeds at ant-swarms, catching small arthropods flushed by ants (Dowsett-Lemaire 1989). The only documented nest was 4 m up in the fork of a tree (Keith et al. 1992). Inferred egg-laying dates range from September to January (Keith et al. 1992).

Acknowledgements

Text account compilers
Benstead, P., Ekstrom, J., Evans, M., Shutes, S., Starkey, M., Symes, A., Taylor, J. & Westrip, J.

Contributors
Barnes, K., Dowsett-Lemaire, F., Dyer, M., Haugaard, J., Kaliba, P., Luhanga, L., Parker, V., Bayliss, J. & Timberlake, J.


Recommended citation
BirdLife International (2017) Species factsheet: Chamaetylas choloensis. Downloaded from http://www.birdlife.org on 17/10/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/10/2017.