Ecology and conservation of a small insular bird population, the Réunion cuckoo-shrike Coracina newtoni

Abstract The Reunion cuckoo-shrike Coracina newtoni is a rare endemic forest bird surviving on Reunion island in the Indian Ocean. Its current population is estimated at 120–150 pairs, restricted within a 16-km2 upland and montane forest area covering a mere 3% of the remaining forest cover of the island. This population has been stable in size and range for at least three decades but it is said to have been more widespread and abundant earlier. Its mountain range is cooler, with higher rainfall and cloud cover and lower prey abundance than the lowlands. Conversely, there are no apparent differences between its forest range and other existing forests, most of them now restricted within the same altitudinal level. It is hypothesized that the species was formerly a mainly lowland forest species which survives in a suboptimal habitat where poor breeding success or survival and lack of more suitable forests prevent it from spreading. Introduced predators, habitat degradation and poaching are additional limiting factors but are unlikely to explain the current status of the Reunion cuckoo-shrike and the difference from that of its Mauritius counterpart Coracina typica. Research guidelines and conservation priorities are suggested, including a feasibility study to establish a second population in the only lowland natural forest patch remaining in Reunion.