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Gabela Akalat Sheppardia gabela



Justification

Justification of Red List category
This poorly known species has a very small range, which is severely fragmented, and its forest habitat is likely to be declining in area, extent and quality. Its population is likely to be highly fragmented and declining. It is therefore classified as Endangered.

Population justification
Using an estimate of the area of available habitat of 327-872 km2, and assuming a territory size of 3 ha per pair the minimum global population is estimated to number 21,800 mature individuals. The area of suitable habitat is probably much smaller than the estimate used (M. Mills in litt. 2007), so this may well be an overestimate: the population is thus precautionarily placed in the band 10,000-19,999 mature individuals. This equates to 15,000-29,999 individuals in total, rounded here to 15,000-30,000 individuals.

Trend justification
The population is suspected to be in moderate decline owing to the ongoing clearance of its habitats for subsistence agriculture.

Distribution and population

Sheppardia gabela is known only from a few forest patches within 40 km of Gabela, on the escarpment of western Angola. A recent brief survey (2003) found that the forest around Gabela has largely been transformed, but three individuals of this species were recorded at a single, large forest block which survives near the village of Kumbira, in regenerating coffee and in secondary bush near the town of Seles (C. Cohen, M. Mills and C. Spottiswoode in litt. 2003, Mills et al. 2004, Ryan et al. 2004). Surveys in 2005 found the species at two additional sites within the known range (Mills 2010). It may possibly occur in other relict patches of forest on the escarpment, but suitable habitat is severely restricted. The species's global range of 1,090 km2 and the estimated local deforestation rate of 20-70% can be used to estimate the area of available habitat at 327-872 km2 (Sekercioglu and Riley 2005). With this information, and assuming a territory size of 3 ha per pair (maximum for well-studied Sheppardia species), the minimum global population is estimated to number 21,800 mature individuals (Sekercioglu and Riley 2005). However, the area of available habitat is probably much smaller than the estimate used (M. Mills in litt. 2007), thus this is considered a maximum population estimate. This calculation may include unsuitable forest habitat, and the deforestation rate may be over 70%, however countering this, the species is common in some modified habitats (Sekercioglu and Riley 2005).

Ecology

It is found in the dense understorey of a few remaining primary and secondary forest patches at or above 1,100 m, but as low as 810 m (Mills et al. 2004). It has been observed in scrubby edges of managed coffee forest, but is probably dependent on nearby, more intact forest. It has been observed mostly at heights of 4-6 m above the forest floor (Sekercioglu and Riley 2005). Radio-tracking showed that the species is also capable of using agricultural areas and secondary growth. However, this could be related to the presence of natural forest nearby (Cáceres et al. 2016). It is probably exclusively insectivorous, gleaning insects from leaves and branches of undergrowth. Its breeding ecology is unknown although birds in breeding condition have been found in September. Two immature birds were trapped in Kumbira Forest in January 2004, probably constituting the first breeding record for the species (Sekercioglu and Riley 2005). Territory size was predicted in the range of other well-studied Sheppardia species, at around 0.5-3 ha per pair (Sekercioglu and Riley 2005), but recent radio-tracking analyses suggest it could be up to 4.3ha (Cáceres et al. 2016). However, the species may contract its home range size even more in disturbed areas (abandonned coffee plantations and secondary growth), though it could be that they are contracting their home ranges to the forest remnants still available in these disturbed habitats (Cáceres et al. 2016).

Threats

It is threatened by loss of habitat from subsistence agriculture, which possibly affects 30% of forest in the Kumbira area (Sekercioglu and Riley 2005). In some areas, 20-70% of canopy trees and all the undergrowth in valley bottoms is being cleared to plant bananas and sweet potatoes (Dean 2001). In other areas, up to 95% of the forest canopy is being removed to plant cassava and maize (Dean 2001). Since the 1930s, shaded coffee plantations have been developed in the forests of the escarpment (Sekercioglu and Riley 2005). It is likely that suitable habitat has increased since the mid-1970s, as civil war has forced out commercial farmers and resulted in the abandonment of shaded coffee plantations (Mills et al. 2004, Sekercioglu and Riley 2005), however, relict coffee plantations are now being encroached by subsistence agriculture (Sinclair et al. 2004). With the return of peace, commercial activities on the Angolan escarpment (such as coffee growing) (Sinclair et al. 2004) are expected to resume, presenting a serious threat to the species (Mills et al. 2004). In particular, the replacement of shade-grown coffee with sun-tolerant varieties could pose a serious threat (Ryan et al. 2004). The marketing of local produce is currently limited by the poor state of the Sumbe-Gabela road, however this is a priority for reconstruction, which would contribute to increased development and agriculture in the area (Ryan et al. 2004). Most of Kumbira Forest was selectively logged before the civil war (Sinclair et al. 2004) and, although there is no evidence of ongoing logging, the forest continues to be a source of firewood (Sekercioglu and Riley 2005).

Conservation actions

Conservation Actions Underway
A protected area of 50 km2 in the region was recommended in the early 1970s, but has not been established (Dean 2001).

Conservation Actions Proposed
Conduct surveys to estimate the population size and ascertain its presence in other forest patches. Survey forest cover in the Gabela region by studying satellite imagery, in order to improve the population estimate (Sekercioglu and Riley 2005). Designate the forest at Gabela as a protected area (the only effective conservation action possible) (W. R. J. Dean in litt. 1999). Implement a conservation strategy for the Angolan escarpment in reaction to the resumption of commercial activities (Mills et al. 2004). Promote ecotourism as a viable supplement to agriculture (as tourism becomes possible) (Sinclair et al. 2004). Study the species's territory size by radio-tracking individuals (Sekercioglu and Riley 2005). Preserve Kumbira Forest through official protection and community-based conservation (Sekercioglu and Riley 2005).

Identification

13 cm. Small, drab, featureless robin. Dull brown upperparts and white to off-white underparts with brown breast-band. White throat contrasts with breast-band. Voice Mournful two-note whistle, repeated; also high pitched weeh-weeh-weeh repeated with intermittent mechanical scraping call. Hints Very shy and difficult to observe.

Acknowledgements

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

Contributors
Cohen, C., Dean, R., Mills, M., Spottiswoode, C. & Cáceres, A.


Recommended citation
BirdLife International (2024) Species factsheet: Gabela Akalat Sheppardia gabela. Downloaded from https://datazone.birdlife.org/species/factsheet/gabela-akalat-sheppardia-gabela on 23/11/2024.
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 23/11/2024.