Report from a BOU-funded project Detecting change in the status and habitat of Hinde’s Babbler Turdoides hindei: 2000 to 2011 PHIL SHAW, 1 * PETER NJOROGE, 2 VINCENT OTIENO 2 & EDSON MLAMBA 2 1 School of Biology, University of St Andrews, St Andrews, Fife KY16 9TS, UK 2 Department of Zoology, National Museums of Kenya, PO Box 40658-00100, Nairobi, Kenya BACKGROUND The globally Vulnerable Kenyan endemic Hinde’s Bab- bler Turdoides hindei has its stronghold in the foothills of Mt Kenya and the Aberdares, where it is associated mainly with patches of scrub and riverine thicket (Statt- ersfield et al. 1998, Njoroge & Bennun 2000, BirdLife International 2012). A decline in its known range, first described in the 1970s, was attributed to scrub clearance for cultivation, perhaps compounded in some areas by human disturbance and hunting (Plumb 1979, Njoroge et al. 1998). Surveys in 1994 and 2000–2001 showed that the species was much less abundant within pro- tected areas than in fertile, densely populated farmland, offering limited scope for conservation through further site designation (Shaw & Musina 2003). The global range of Hinde’s Babbler lies predomi- nantly within the catchments of the upper Tana River, with outlying populations in Meru District, Machakos, Kitui and Nziu (Shaw et al. 2003). By 2001 the species was known from just seven main areas, and was thought to have a global population of c. 1500–5600 birds. Although scrub clearance has impacted on the species’ range and population, its effect may have been partly mitigated by the spread of the exotic invasive Lantana camara, which provides scrub cover in areas previously cleared of native shrubs, enabling the Babbler to persist in, and possibly to re-colonize, intensively farmed land (Njoroge & Bennun 2000). Like most members of its genus, Hinde’s Babbler breeds cooperatively, groups typically comprising three to four adults (range 1–8), often accompanied by one or two juveniles (Njoroge & Mutinda 1996, Shaw & Musi- na 2003). Some groups include individuals with exten- sive light feathering on the chest, head and back, sometimes distributed asymmetrically, a trait interpreted by Plumb (1979) as possible evidence of inbreeding. In 2011 we reassessed the global range of Hinde’s Babbler and resurveyed three sites previously surveyed in 2000–2001, to determine whether changes had occurred in its known range, abundance, demography or habitat over the intervening decade. To determine the relationship between plumage type, population density and breeding success we assigned a plumage score to all individuals seen sufficiently clearly, noting their age class and group composition. GLOBAL RANGE Changes in Hinde’s Babbler’s global range were estimated from the number of occupied 10 9 10-km squares (its Area of Occupancy) and from the number of squares bounded by these known sites (its Extent of Occurrence). Three time periods were compared: 1900–1970, 1971–1990 and 1991–2011. Since its discovery in 1900, Hinde’s Babbler has been recorded in 53 squares, indicat- ing an Area of Occupancy of c. 5300 km 2 , its Extent of Occurrence spanning c. 22 700 km 2 . While the species’ Area of Occupancy in each period had increased progres- sively, its Extent of Occurrence contracted between 1900–1970 and 1971–1990, and then expanded during 1991–2011, as a result of new discoveries on the periph- ery of its range. Notwithstanding these apparent exten- sions, several aspects of the species’ status give cause for concern. During 1991–2011, Hinde’s Babblers were recorded from 31 squares (59% of its historical range), but was unrecorded in 14 squares from which it had been reported in 1971–1990, mainly within intensively cultivated areas near to the core of its range. DEMOGRAPHY AND PLUMAGE VARIATION In July 2011 we re-surveyed 74 km of watercourse tran- sects in Machakos, Kianyaga and Mukurwe-ini Valleys Important Bird Areas (IBAs), using field methods identi- cal to those used in 2000–2001. Recordings of Hinde’s Babbler calls were played for 1–2 min at intervals of 50 m, ensuring that each transect was sampled indepen- dently of variation in habitat quality. Each group was observed for at least 10–15 min. Individuals were assigned to one of three age categories, based on eye col- our, gape and plumage. In 2000–2001, habitat details were recorded within sets of four contiguous 50 9 50-m quadrats, each set located 250 m apart, using GPS. Hab- itat points were relocated in 2011, to within a median of 11 m. At each point, the altitude, topography, slope, land use and width of watercourse were recorded, and *Corresponding author. Email: ps61@st-andrews.ac.uk © 2013 British Ornithologists’ Union Ibis (2013), 155, 428–429