Data Zone
Justification of Red List category
This owl is listed as Endangered because it has a very small, severely fragmented range, within which its population and the quality of its habitat is declining. In Tanzania the owl inhabits a coastal forest that, while still extensive, is under some pressure from fires, encroachment and tree-cutting.
Population justification
In Arabuko-Sokoke, a population of c.1,000 pairs (stable between 1984 and 1998) occurs in c.220 km2 of forest. In the East Usambaras, there are c.97 km2 of suitable habitat and densities range from less than 1.5 pairs/km2 up to 3-4 pairs/km2, suggesting a population in the low hundreds. The total population is estimated to number at least 2,500 individuals and is placed in the band 2,500-9,999 mature individuals. This equates to 3,750-14,999 individuals in total, rounded here to 3,500-15,000 individuals.
Trend justification
This species's population is suspected to be declining in line with habitat degradation within its range. Unsustainable removal of large Brachylaena trees, which were thought to be its main resource for nest-cavities, was suspected to be critical, but there may now be few if any of these trees remaining in Arabuko-Sokoke. Playback surveys in 2005 and 2008, and compared with data from 1993, suggest that the species may have undergone declines of 22.5 % in 16 years in Arabuko-Sokoke (Virani et al. 2010). Climate change could lead to a decline in suitable habitat of over 60% by 2080 (Monadjem et al. 2013), but this is considerably more than 3 generations for this species, and the likely overall rate of population decline over this time period has not been estimated.
Otus ireneae was believed to be endemic to the Arabuko-Sokoke Forest in coastal Kenya, but in 1992 it was found in the lowlands of the East Usambara Mountains of Tanzania as well (Evans 1997a). In Arabuko-Sokoke, a population of c.1,000 pairs occurs in c.220 km2 of forest (Virani 1995b) - this population was suspected to have been stable between 1984 and 1998 (Virani 2000a), but playback surveys in 2005 and 2008, and compared with data from 1993, suggest that the species may have undergone declines of 22.5 % in 16 years (Virani et al. 2010). In the East Usambaras, there is c.97 km2 of suitable habitat and densities range from less than 1.5 pairs/km2 up to 3-4 pairs/km2, suggesting a population in the low hundreds (Evans 1997b). The species might also occur in the Mundane Range, near the Kenya-Somalia border (Virani 1995a, 1995b) and the Dakatcha Woodland. The discovery of a very small population on the edge of Marafa Forest to the north of Arabuko-Sokoke suggests further exploration of the overall area might reveal more pockets of habitat holding marginal or remnant populations (C. Jackson in litt. 2004), and this may possibly be true for lowland areas of the East Usambaras (N. Burgess in litt. 2007), although it was not found at three previously unsurveyed Brachylaena woodland sites in north-east Tanzania (Cordeiro and Githiru 2000). Surveys in Kaya forests along the Kenyan coast south of Mombasa did not locate the species (M. Virani in litt. 2007).
In Arabuko-Sokoke, it occurs mostly in good quality Cynometra forest (787 pairs in 99 km2), and at much lower densities in an additional 120 km2 of secondary or more disturbed Cynometra forest (Virani 1995b, Evans 1997b). It roosts and forages in the dense lower half of the Cynometra canopy and possibly nests in natural cavities in large or old Brachylaena trees (Virani 1994, 1995b). It feeds mainly on beetles (Cameron 2003), with 91% of the diet in one study in Arabuko-Sokoke found to consist of Coleoptera (Virani 2008). In the East Usambaras it occurs in lowland coastal forest with a mixed tree species composition up to 400 m, which is taller and structurally different to that in Arabuko-Sokoke (Evans 1997b, N. Burgess in litt. 2007). It has a home range of 12-14 ha (Virani 1995b, 2000b).
In Arabuko-Sokoke, unsustainable (and often illegal) extraction of Brachylaena huillensis for wood-carving and firewood may have reduced the species's breeding success (Virani 1995b, M. Z. A. Virani in litt. 1999), and there may now be few if any of these trees remaining (N. Burgess in litt. 2012). O. ireneae is probably long-lived (Cameron 2003), so the resulting declines might not be observed for some time. In the East Usambaras, most lowland forest outside reserves has already been cleared for agriculture, and there is a programme to reserve the remaining patches as village forest reserves (N. Burgess in litt. 2007, 2012). Government-owned forest reserves suffer from pit-sawing of timber and pole-cutting (Evans et al. 1994, N. Burgess in litt. 2007). In addition, Arabuko-Sokoke forest is under threat from titanium mining (Cameron 2003, N. Burgess in litt. 2007). It is possible that the species breeds opportunistically in response to rain, however the seasons in Kenya have deteriorated into more irregular rains and increased droughts (Cameron 2003). Climate change is predicted to have an effect on this species, with a potential 64% decline in the amount of suitable habitat by 2080 (Monadjem et al. 2013).
Conservation Actions Underway
CITES Appendix II. Arabuko-Sokoke Forest is the focus of a project aiming to promote long-term conservation through community management (Fanshawe 1997). Within the forest reserve there is a 43 km2 strict nature reserve, although this does not contain good quality owl habitat (Virani 1995a, 1995b, 2000a, N. Burgess in litt. 2007). A two-yearly census of the owls in Arabuko-Sokoke has been initiated (M. Z. A. Virani in litt. 1999). The Peregrine Fund has been funding the study of the species in Arabuko-Sokoke, including the radio-tracking of birds (Cameron 2003). In the East Usambaras, the main habitat is found in the Kwamgumi-Bamba-Segoma forest reserves, and also in the lowland forests within the private Kwamtili estate (N. Burgess in litt. 2007). Efforts were started to link all of these forest areas together within a single forest reserve managed by the central government, but this has not been concluded and additional support is needed to complete the process (N. Burgess in litt. 2007, 2012). Kenya's National Environment Management Authority and Kenya Forest Service have withstood pressure for habitat alteration in the Dakatcha Woodland (Mwongela 2012).
15 cm. Very small owl with slight ears. Both grey and rufous forms occur. Heavily barred, streaked and vermiculated like most scops-owls Otus spp. Similar spp. African Barred Owlet Glaucidium capense much bigger with obviously barred, not vermiculated, underparts. Voice Soft too too too, repeated 10 or more times per minute. Hints At day-roost in thicket, usually in pairs, compresses body and holds ears erect and eyes drawn closed to slits. Most easily located in the Cynometra woodland of Arabuko-Sokoke Forest between Kilifi and Malindi on the Kenya coast. It feeds on insects, mainly beetles.
Text account compilers
Ekstrom, J., Evans, M., Harding, M., Khwaja, N., Pilgrim, J., Shutes, S., Starkey, M., Symes, A., Taylor, J., Westrip, J.
Contributors
Jackson, C., Sawe, C., Burgess, N., Kilahama, F., Bennun, L., Kahemela, A., Cordeiro, N., Virani, M., Nderumaki, M.
Recommended citation
BirdLife International (2024) Species factsheet: Sokoke Scops-owl Otus ireneae. Downloaded from
https://datazone.birdlife.org/species/factsheet/sokoke-scops-owl-otus-ireneae on 29/12/2024.
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 29/12/2024.