EN
Gabela Bushshrike Laniarius amboimensis



Justification

Justification of Red List category
This poorly known species is believed to have a very small population of <2,500 mature individuals, and to be experiencing declines due to ongoing habitat degradation. It is therefore classified as Endangered. Further evidence of population size may lead to a change in classification in the future.

Population justification
The population size for this species has not been directly quantified, but it is safe to estimate, given the limited sightings by researchers actively looking for the bird, that there are fewer than 1,000 pairs (M. Mills in litt. 2020) in the global population. M. Mills (in litt. 2020) reports not sighting this species in Kumbira (the best known site for this species) since 2017, and that this is not atypical across the whole of the species range. Extensive surveys along the central escarpment in 2018-2019 found three pairs over ten days of searching (M. Mills in litt. 2020). Only one pair is now known at Bango, where previously there had been several (M. Mills. in litt. 2020). It is also reported by P. Vaz Pinto (in litt. 2020) that the species is now rarely observed in Kumbira, and that only two pairs were located after several weeks of searching in 2019. Further surveys elsewhere in the range only reported one additional pair. It is also likely that over the past several years, birdwatchers have observed no more than 10 pairs (P. Vaz Pinto in litt. 2020). Additionally, L Fishpool (in litt. 2020) only observed one pair of Gabela Bush-shrike after three days actively searching for the bird in places it had been previously recorded, and using playback recordings in the hope of generating a response. Therefore, the population size is tentatively placed here in the 1,000 - 2,499 band.

Trend justification
The population is inferred to be in decline owing to the loss and degradation of the species's forest habitat through clearance and modification for cultivation (Mills, in litt. 2020; Vaz Pinto, in litt. 2020; Fishpool, in litt. 2020). The likely rate of decline, however, has not been estimated.

Distribution and population

Laniarius amboimensis was formerly known only from a restricted area around Gabela on the escarpment zone of Angola (Dean 2000); however, surveys conducted in 2005 have extended its known range (Mills 2010). After 1960 there were no records until single pairs were found twice in three days in September 1992, in mixed-species flocks. In 2003, it was found to be common in thickets in secondary forest and primary forest at Kumbira, and heard in forest near the Sumbe-Gabela road (Ryan et al. 2004). In January 2004, the species was recorded in Kumbira Forest and by a nearby road (Sekercioðlu and Riley 2005). During surveys conducted in 2005, it was recorded c.30 km north of Gabela and as far south Gungo (Mills 2010). Further surveys in Kumbira Forest in 2010 found it to be present in 2 separate zones of the forest, but absent from most of the area (Cáceres et al. 2015). There is also a specimen at Lubango Museum from Egito, Benguella (Mills 2010). The species is judged to be uncommon, and its population is estimated to include fewer than 2,500 mature individuals. Further surveys are required to establish specific population densities or population size estimates for this species.

Ecology

It is found in the undergrowth of drier evergreen forest above 730 m, and shows some tolerance of habitat modification, having been recorded in overgrown coffee plantations (Mills 2010) and secondary growth, particularly with dense understorey and lower canopy vegetation (Sekercioðlu and Riley 2005, Mills 2010, Cáceres et al. 2015). Radio tracking of two individuals has given a possible home range size of 3.9-5.3 Ha (Cáceres 2013).

Threats

It is threatened by habitat loss through the encroachment of subsistence and slash-and-burn agriculture (Sekercioðlu and Riley 2005, Mills 2010), which has been estimated to possibly affect 30% of forest in the Kumbira area (Sekercioðlu 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). The removal of the all understorey vegetation renders habitat completely unsuitable for the species (Mills 2010). In other areas, up to 95% of the forest canopy has been removed to plant cassava and maize (Dean 2001). The cultivation of manioc and maize is now very prevalent within the species's range (F. Olmos in litt. 2011). Since the 1930s, shaded coffee plantations have been developed in the forests of the escarpment (Sekercioðlu and Riley 2005). With the return of peace, commercial activities on the Angolan escarpment (such as coffee growing) (Sinclair et al. 2004) are expected to resume (Mills et al. 2004). The marketing of local produce is currently limited by the poor state of the Sumbe-Gabela road (Ryan et al. 2004). 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 on-going logging, the forest continues to be a source of firewood (Sekercioðlu and Riley 2005). Current activities such as selective logging and shaded coffee-growing may not seriously threaten the species, as it is tolerant of fairly degraded habitats (Ryan et al. 2004, Mills 2010).

Conservation actions

Conservation Actions Underway
A protected area of 50 km2 was recommended for the area in the early 1970s (Dean 2001), but this has not been established (M. Mills in litt. 2020).

Conservation Actions Proposed
Conduct urgent surveys to determine its distribution and population size (P. Vaz Pinto in litt. 2020). Study the species's habitat requirements. Designate protected areas to safeguard suitable habitat. 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 (Sinclair et al. 2004). Preserve Kumbira Forest through official protection and community-based conservation (Sekercioðlu and Riley 2005).

Identification

20 cm. Black-and-white forest shrike. Predominantly black-and-white with rusty cap. Similar spp. Differs from very similar Luehder's Bush-shrike L. luehderi and Orange-breasted Bush-shrike L. brauni by having clear white underparts. Voice Throaty calls of waaark and whook, very similar to that of L. luehderi.

Acknowledgements

Text account compilers
Benstead, P., Ekstrom, J., Clark, J., Shutes, S.

Contributors
Dean, R., Fishpool, L., Mills, M., Olmos, F., Vaz Pinto, P., Taylor, J. & Westrip, J.R.S.


Recommended citation
BirdLife International (2024) Species factsheet: Gabela Bushshrike Laniarius amboimensis. Downloaded from https://datazone.birdlife.org/species/factsheet/gabela-bushshrike-laniarius-amboimensis 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.