Following the recognition of Sumatran Leafbird as a species in 2006, the species was assessed as being of Least Concern, on the basis that it did not approach any of the thresholds for Vulnerable. This restricted range Sumatran endemic species was thought to be common within its range, but was poorly known. However, it was considered to be declining due to the very high rate of habitat loss throughout Sumatra, but as much of the species’ range is at higher altitudes than the majority of habitat loss.
In recent years a very large number of wild-caught leafbirds have been supplied to the Indonesian cage-bird trade, and Sumatran Leafbird was included in the secondary list of species arising from the Asian Songbird Crisis Summit in 2015 that are declining due to trade. 14 individuals were observed in a survey of the largest markets across Java in 2014 (Chng et al. 2015), but previous surveys have not identified many leafbirds to species (e.g. Shepherd et al. 2006) and confusion in identification prevented an analysis of the numbers and prices of Sumatran Leafbird in trade in a recent Sumatran investigation (Harris et al. 2015). Greater Green Leafbird has been the primary target in Sumatra in the last two years, a trade that alarmingly seems to have now shifted to importing that species from Malaysia (Eaton et al. 2015, J. Eaton in litt. 2016), suggesting that it has become difficult to source sufficient quantities of that species from Sumatra. Despite the frustrating lack of data, it is apparent that this species is being trapped and that this is likely to be contributing significantly to a decline in population. Additionally, the collapse of populations of Greater Green Leafbird could lead to any accessible leafbird being targeted as substitute species, with those present on Sumatra most accessible due to the existing trade network.
The species was classified as ‘Severely Declining’ by a process of expert review (Harris et al. 2015), and while not quantified, it could be taken to infer a population decline in the order of 30-49% over the period of three generations (12.6 years). On this basis the species is proposed to qualify for listing as Vulnerable under criterion A2cd + A3cd + A4cd.
Chng, S. C. L., Eaton, J. A., Krishnasamy, K., Shepherd, C. R. & Nijman, V. 2015. In the market for extinction: an inventory of Jakarta’s bird markets. Petaling Jaya, Selangor, Malaysia: TRAFFIC.
Eaton, J.A., Shepherd, C.R., Rheindt, F.E., Harris, J.B.C., van Balen, S. (B.), Wilcove, D.S. and Collar, N.J.C. 2015. Trade-driven extinctions and near-extinctions of avian taxa in Sundaic Indonesia. Forktail 31: 1-12.
Harris, J. B. C., Green, J. M. H., Prawiradilaga, D. M., Giam, X., Giyanto, Hikmatullah, D., Putra, C. A. & Wilcove, D. S. 2015. Using market data and expert opinion to identify overexploited species in the wild bird trade. Biol. Conserv. 187: 51–60.
Shepherd, C. R. 2006. The bird trade in Medan, North Sumatra: an overview. BirdingASIA 5: 16–24.