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Ethiopian Bush-crow Zavattariornis stresemanni
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Justification
This species's population was believed to be declining very rapidly as a result of habitat alteration within its small range, and it is therefore listed as Endangered. More recent evidence indicates that the population may be stable, and confirmation of this might make the species eligible for downlisting in future.

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.

Identification
30 cm. Small, starling-like crow. Pale grey head and body. Black wings and tail. Bare, blue skin around eye. Sexes similar, juvenile slightly more dingy. Similar spp. Non-breeding Wattled Starling Creatophora cinerea is much smaller, with pale rump. Voice Harsh, rasping calls and chattering. Hints Occurs in groups of 4-10, often in association with White-crowned Starling Spreo albicapillus. Common in Acacia savanna north, south and east of Yabello town, southern Ethiopia.

Distribution and population
Zavattariornis stresemanni is confined to the area around Yabello, Arero, and Mega, southern Ethiopia. The nucleus of the species’s range is in the southern part of the Yabello Wildlife Sanctuary (Borghesio and Giannetti 2005). It has a highly restricted distribution, occurring only patchily within an area that extends just 160 km from north to south and less than 100 km from east to west (Donald et al. 2012). The species’s area of occupancy appears to be defined by a unique climate pocket that is cooler, dryer and more seasonal than the surrounding area (Donald et al. 2012). Within this limited climate window it favours a park-like landscape of grazed pasturelands interspersed with taller vegetation. Models predict an area of just 6,000 km2 to be climatically optimal, of which perhaps 4,500 km2 has suitable vegetation (Donald et al. 2012). There is no historical data on the population size or distribution of the species but brief surveys in 1989 suggested densities had remained constant through the 1980s. Surveys in 1996 found the species to be common within its restricted range (EWNHS 1996). However, 80% declines in encounter rates on roadside counts in the Yabello Wildlife Sanctuary between 1989 and 2003, suggested that the population was decreasing very rapidly (Borghesio and Giannetti 2005), although doubt has been expressed about the severity of these apparent declines (Mellanby et al. 2008, Donald et al. 2012) and local people report that the population has remained stable (P. Donald in litt. 2012).


Population justification
Based on nest-counts, Donald et al. (2012) estimate a global population of at least 9,000 breeding pairs, however, as active nests typically have several nest-helpers there may also be a significant additional non-breeding population. It is placed here in the band 10,000-19,999 mature individuals, but may well prove to be larger.

Trend justification
Encounter rates in the Yavello Wildlife Sanctuary declined by 80% between 1989 and 2003 (Borghesio and Giannetti 2005), which covers a large part of the species's range, and declines are presumed to be continuing, owing to on-going habitat conversion and degradation. The overall rate of decline is estimated to be very rapid. More recent studies suggest that the species's population in fact may be stable (P. Donald in litt. 2012), however a rapid ongoing decline is retained here until this can be confirmed.

Ecology
It is found in open, semi-arid areas of short-grass savanna with scattered low Acacia bushes at c.1,700 m (EWNHS 1996), and is common in the vicinity of human settlements (P. Robertson in litt. 1998, Gedeon 2006). It feeds mostly on arthropods (Gedeon 2006, Donald et al. 2012) and, outside the breeding season, is gregarious (EWNHS 1996). It mainly feeds by extracting pupae and larvae from soil or from under cattle dung; however it also feeds on flying insects such as Lepidoptera, and may search for larvae in rotten branches and pick parasites from cattle (Gedeon 2006). The species exhibits a range of complex behaviours, including play, allopreening, allofeeding, cooperative nesting and sentinel duty (Gedeon 2006). Breeding takes place in February/March, and can involve cooperation with usually one, but possibly up to four, extra-pair individuals, which each may help more than one nesting pair (Gedeon 2006). The normal nest-site is in the top of an Acacia bush (2.5-10 m high) (Gedeon 2006) and clutch-size is up to six. It has been recorded breeding in May/June, which would indicate either that birds are double-brooded or have an extended breeding season. Breeding pairs range for about 2 ha during nest building (Gedeon 2006).


Threats
Analysis of satellite imagery between 1986 and 2002 indicates that there has been an increase in vegetation density in Yabello Wildlife Sanctuary through bush encroachment, probably as a result of increased grazing pressure from livestock, the enforcement of fire suppression in the sanctuary and the disappearance of wild herbivores (Borghesio and Giannetti 2005). As the species prefers more open habitat, this is likely to be the primary cause of any population declines. Political and administrative intervention has encouraged more maize cultivation in the species's range, in an effort to develop a monetary economy and promote self-sufficiency and the constitution of food stocks in an area that was dominated by nomadic pastoralism 10-20 years ago (Gedeon 2006). Expanding cultivation is thought to have caused population decreases near Mega (Borghesio and Giannetti 2005), and is driving the large-scale clearance of Acacia stands near Derido and Yabello (Gedeon 2006). The partial clearance of dense Acacia scrub to allow grass-growth for cattle does not appear to have affected the species and may even benefit it (P. Robertson in litt. 1998). However, recent research indicates that tall Acacia bushes, in which this species nests, are being cleared intensively (for both firewood and grazing land), and this may now be having a negative impact on the species (A. Shimelis in litt. 1999). Acacia stands in areas surrounding villages tend to occupy land that is particularly suitable for cultivation, and with a rapid increase in the human population, the continued loss of the species's habitat is predicted (Gedeon 2006). Over recent years Yabello has become an administrative centre for Borena Zone, with a continually expanding residential area, signifying human population growth and land use changes in an important area for the species (Gedeon 2006). However, given the species’ specialised climatic requirements, the greatest threat to its long-term survival is likely to be climate change (Donald et al. 2012).

Conservation Actions Underway
A detailed study of the species's ecology is currently underway (M. Wondafrash in litt. 2007), and in 2012 a detailed study of its likely responses to climate change will commence. Yabello Wildlife Sanctuary, which was designated in 1985, has recently been replaced by Yabello National Park, the boundary of which has yet to be finalised. Current management plans for the new National Park aim to promote sustainable resource management across the wider landscape and strict formal protection at key sites (Donald et al. 2012). A species management plan is in the process of being written as part of a wider project on southern Ethiopian endemic birds.
Conservation Actions Proposed
Donald et al. (2012) propose the following key actions: 1. Ensure that the new National Park encourages the sustainable use of its resources in areas of importance to the Bush-crow and does not exclude people and their grazers; 2. Establish a monitoring protocol to assess changes in the range and population of the Bush-crow in response to habitat and climate change; 3. Secure and increase the area of grassland by clearance of woody cover, with burning or perhaps by using camels, within the area of climatic suitability, and strengthen traditional gada rangeland management; 4. Ensure the retention of taller vegetation, even single trees (particularly large acacias and Balanites), in newly cleared areas; 5. Control the spread of agriculture into grasslands; 6. Undertake further work on the species to understand better its ecology, threats and requirements.


References
Borghesio, L.; Giannetti, F. 2005. Habitat degradation threatens the survival of the Ethiopian bush crow Zavattariornis stresemanni. Oryx 39: 44-49.

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.

Donald, P. F., Gedeon, K., Collar, N. J., Spottiswoode, C. N., Wondafrash, M. and Buchanan, G. M. 2012. The restricted range of the Ethiopian Bush-crow Zavattariornis stresemanni is a consequence of high reliance on modified habitats within narrow climatic limits. Journal of Ornithology doi:10.1007/s10336-012-0832-4.

EWNHS. 1996. Important Bird Areas of Ethiopia: a first inventory. Ethiopian Wildlife and Natural History Society, Addis Ababa.

Gedeon, K. 2006. Observations on the biology of the Ethiopian Bush Crow Zavattariornis stresemanni. Bulletin of the African Bird Club 13(2): 178-188.

Mellanby, R. J.; Ross, B.; Watt, A.; Wondafrash, M.; Ewnetu, M.; Broadhurst, C.; Critchlow, R.; Dadesa, A.; Deas, T.; Enawgaw, C.; Gebremedhin, B.; Graham, E.; MacLean, S.; McKean, M.; Collar, N. J.; Spottiswoode, C. N. 2008. Distribution, abundance and habitat preferences of White-tailed Swallow Hirundo megaensis and Ethiopian Bush-crow Zavattariornis stresemanni, two southern Ethiopian endemics. Bird Conservation International 18(4): 395-412.

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

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Text account compilers
Ekstrom, J., Harding, M., Shutes, S., Starkey, M., Taylor, J., Allinson, T, Symes, A.

Contributors
Borghesio, L., Robertson, P., Shimelis, A., Wondafrash, M., Donald, P.

IUCN Red List evaluators
Butchart, S., Taylor, J.

Recommended citation
BirdLife International (2014) Species factsheet: Zavattariornis stresemanni. Downloaded from http://www.birdlife.org on 01/10/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 01/10/2014.

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.

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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.

Additional resources for this species

ARKive species - Ethiopian bush-crow (Zavattariornis stresemanni) 0

Key facts
Current IUCN Red List category Endangered
Family Corvidae (Crows and jays)
Species name author Moltoni, 1938
Population size 10000-19999 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 4,600 km2
Country endemic? Yes
Links to further information
- Additional Information on this species