VU
Pemba Scops-owl Otus pembaensis



Justification

Justification of Red List Category
This species is listed as Vulnerable because it has a single small population which is continuing to decline as a result of habitat loss and degradation, owing primarily to a local agricultural trend away from plantation crops and towards open farmland.

Population justification
M. Virani (in litt. 2005) estimated the population to number 1,500 breeding pairs (3,000 mature individuals), based on preliminary data on the extent of various habitats, and densities of the species in these different habitats. This estimate equates to 4,500 individuals in total.

Trend justification
The species was judged to be in rapid decline based on observations of habitat loss from surveys in 2005 (Virani 2005).

Distribution and population

Otus pembaensis is endemic to Pemba, some 55 km off the coast of northern Tanzania. Although occurring over most of the island, it is largely confined to the two small remaining native forests; Ngezi (14 km2) and Msitu Mkuu (3 km2) (Catry et al. 2000, Virani 2005, M. Virani in litt. 2005). The global population size is estimated at c.1,500 pairs (M. Virani in litt. 2005). Global population trends have not been quantified, and populations appeared to be stable (del Hoyo et al. 1999) or declining slightly owing to slow habitat conversion. However, observations of habitat loss from surveys in 2005 suggest that the species is in rapid decline (Virani 2005).

Ecology

This species occurs in a number of forested habitats, such as dense areas in clove and mango plantations (Virani 2005), but is much more common in native, primary forest. Surveys in February 2005 recorded owl responses per transect point. Relative abundances for various habitats were: 2.9 (primary forest), 1.6 (secondary forest), 0.7 (old growth cloves), and 0.4 (settlements with old trees) responses respectively. No responses were obtained in open farmland, villages, or towns (M. Virani in litt. 2005). Breeding biology is unknown, but it probably breeds from August-October in tree holes (König et al. 1999a).

Threats

Decreasing global clove prices led to the conversion of some old clove plantations (which offered suitable habitat) to open farmland growing rice and cassava (Catry et al. 2000, Virani 2005, M. Virani in litt. 2005). The human population of Pemba continues to rise (400 individuals/km2, and increasing by 5% per year [Siex 2011]), and although agriculture remains small-scale the need for crop-land is intensifying rapidly (J. Wolstencroft in litt. 2007, N. Burgess in litt. 2012). The vast majority of the human population is dependent upon shifting cultivation and forest products, such as building poles, firewood, and charcoal. Due to the high price of electricity, even the urban population is heavily reliant on firewood and charcoal for cooking, and Zanzibar as a whole is losing an estimated 1.2% of its forest each year, leading to increasing fragmentation and rapidly diminishing any potential to maintain and restore connectivity of forest patches (Siex 2011). Some native forest has also been recently converted to rubber plantations (Virani 2005). Ras Kiuyu forest has been heavily exploited for building materials, lime burning and fuel wood (A. Hija in litt. 2005). Msitu Mkuu Forest Reserve is subject to illegal exploitation (A. Hija in litt. 2005). Development of tourism may require infrastructure that passes through remaining forest (A. Hija in litt. 2005, B. Peters in litt. 2005). Non-native House Crows Corvus splendens may also pose a threat (F. Reid in litt. 2005).

Conservation actions

Conservation Actions Underway
Protected areas on Pemba include Ngezi-Vumawinbi Nature Reserve, Msitu Mkuu Forest Reserve and Ras Kiuyu Proposed Forest Reserve (Siex 2011). There are also 13 community forests which include high protection and low impact use zones (Siex 2011).

Conservation Actions Proposed
Continue studies to determine rates of habitat destruction (A. Hija in litt. 2005, M. Virani in litt. 2005). Conduct in-depth population studies (A. Hija in litt. 2005, M. Virani in litt. 2005). Carry out research into the species's ecology and habitat requirements (A. Hija in litt. 2005, Virani 2005, M. Virani in litt. 2005). Control illegal activities within the forest reserves (A. Hija in litt. 2005). Improve sustainable tourism facilities at Ngezi Nature Reserve (N. Burgess in litt. 2012). Protect additional areas of forest and off-shore islands (J. Wolstencroft in litt. 2007). Promote sensitive tourist development (J. Wolstencroft in litt. 2007). Carry out survey work to determine if there is potential to restore connectivity of forest patches via enrichment planting (Siex 2011).

Identification

21 cm. A medium-sized scops-owl with short ear-tufts. Varies from pale rufous-brown with light streaking on head and faint barring below, to bright rich russet all over. Similar spp. Barn Owl Tyto alba, the only other owl on Pemba Island, is much larger and very different in appearance. Voice Hoo repeated in long sequence at intervals of 0.5-1 second. Pairs duet, with note of male shorter, and lower in pitch.

Acknowledgements

Text account compilers
Butchart, S., Ekstrom, J., Khwaja, N., Pilgrim, J., Robertson, P., Starkey, M., Symes, A., Taylor, J., Westrip, J.

Contributors
Catry, P., Virani, M., Burgess, N., Wolstencroft, J., Peters, B., Hija, A., Reid, F.


Recommended citation
BirdLife International (2021) Species factsheet: Otus pembaensis. Downloaded from http://www.birdlife.org on 08/03/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 08/03/2021.