Data Zone
Justification of Red List category
The population is believed to be declining at a very rapid rate due to exceptionally high rates of trapping to supply the cage bird trade. Market data indicates that this species is over-exploited, and the species has been reported to have become rare or to have disappeared from large regions where it was previously common. Expert judgment has assessed that the rate of this decline is suspected to have exceeded 50% within the past ten years. In the absence of any expectation of a reduction in market demand or restriction on trapping activity, the decline is expected to continue at this very rapid rate. Thus, the species qualifies for Endangered.
Population justification
The population size is unknown, but the species is described as scarce. Subspecies C. s. zosterops had previously been described as common where habitat remains (Wells 2016), but currently the evidence suggests that birds are being trapped throughout the range and have either disappeared or become very rare at many sites throughout Indonesia and now Peninsular Malaysia as well (Eaton et al. 2015, J. Eaton in litt. 2016, Bas van Balen in litt. 2016).
Trend justification
Evidence suggests that it is being trapped throughout the range and has either disappeared or become very rare at many sites throughout Indonesia and Peninsular Malaysia (Eaton et al. 2015, J. Eaton in litt. 2016, Bas van Balen in litt. 2016), hence a continuing decline is inferred. The population is suspected to be declining at a rapid to very rapid rate due to tremendous levels of trapping to supply the cage bird trade. This species was present at very low numbers in the markets at the turn of the century, with none recorded in Medan in 1997 and 1998 then 110 observed in the following three years (Shepherd 2006). Numbers slowly increased with an annual number traded through the markets in Medan estimated at 842 birds during 2012-2013 (Harris et al. 2015). Since then however, the species has suddenly come into fashion (Chng et al. 2017, Eaton et al. 2015), and right now vast numbers are being traded. J. Eaton in litt. (2016) states that 5,000 individuals per month are currently being imported from Sarawak into Kalimantan. Chng et al. (2017) also report a dealer trading 6,000 individuals from Malaysian Borneo to Kalimantan. In Kalimantan it was stated by shop owners to be the species in highest demand, hardest to find (supply) and to be increasing most rapidly in price (A. Miller in litt. 2016), clearly indicating that a species that should be abundant may be close to extinction in West Kalimantan (Chng et al. 2017). In west Java, the cost of an individual in 2014 was US$ 44 (Chng et al. 2015); in September 2016 one was priced at US$ 99 (Chng et al. 2017). Such a price rise while supply (numbers counted in markets) is still high is a strong indication of an over-exploited species suffering declines (Harris et al. 2015). Expert opinion from the IUCN SSC Asian Songbird Trade Specialist Group (ASTSG in litt. 2018) considers that the current suspected rate of decline in the species exceeds 50% and, in the absence of any expectation of a reduction in market demand or restriction on trapping activity, is expected to continue at this very rapid rate. Symes et al. (2018) used expert opinion on desirability and estimates of the degree of accessibility of the range to trapping to estimate a future population decline of 55% due to trapping over the next three generations, and also estimated rates of deforestation within the range to be 14% over the past three generations, a rate that was projected to continue into the future.
The species's range is throughout the Sundaic lowlands from south Myanmar and southwest Thailand south through Malaysia, Borneo and the Greater Sundas, Indonesia.
A species of lowland evergreen forest, including secondary forest and occasionally heavily wooded parkland and certain plantations (Wells 2016). Occurs from sea level to 1,100 m (Wells 2016). Diet is principally arthropods and fruit, with the former gleaned from foliage. Joins mixed-species feeding flocks.
The number of individuals observed at bird markets in Indonesia has increased dramatically in recent years. The species is particularly desirable due to its ability to rapidly learn the song phrases of other species, and is a category in the competitive singing events held throughout Java. Large numbers have been confiscated along trading routes into Java (S. Chng in litt. 2016), but there are reports of many times the amount seized being imported on a monthly basis (J. Eaton in litt. 2016). The likely estimated population loss due to trapping over the next three generations is 55% (Symes et al. 2018). A 2018 survey of bird ownership involving over 3,000 households in all six of Java’s provinces also estimated that 59,981 ± 27,210 individuals, and an unknown proportion of 1,448,692 ± 448,600 leafbirds are currently kept in Java alone (Marshall et al. 2020). Habitat loss may have played an ancillary role in the decline through increasing the proportion of the global population of the species accessible to trappers, and is also causing a decline in the area of suitable habitat estimated to be 14% (Symes et al. 2018).
Conservation Actions Underway
The species has been successfully bred in a Singapore facility at Jurong Bird Park, with one chick moved to a Breeding and Research centre for hand-rearing (Kumar et al. 2018).
Conservation Actions Proposed
Enforcement of national laws regarding quotas of wild-caught species for the cage bird trade must be prioritised. Investigation into the impacts and extent of trapping networks throughout Borneo and Peninsular Malaysia is also required. Basic knowledge is lacking in whether there is now any sustainable trade possible for this species. There may be the possibility of investigating the opportunity cost of trapping versus supplying captive-bred birds for this species, but the rate of decline at present makes prevention of trapping from the wild the highest current priority. Systematic monitoring of bird markets and suppliers is needed throughout the range, covering numbers, price and attitudes of sellers.
Comparison of densities or encounter rates at sites first surveyed in the late 20th century would provide some quantification of the rates of decline and provide a baseline for further monitoring. A common birds monitoring program in a sample of forests throughout the Sundaic region would enable usable estimates of population trends within a few years. Continued assessment of deforestation rates annually.
Management of protected areas should include management of trapping activities. Petition for the addition of the species to CITES appendix II. Enforcement of protected species status, and of provincial quotas, should they be introduced, will be essential. The species was added to the list of those protected under Indonesian law in August 2018, but enforcement of the law is now essential (there is now now legal trade in the species in Indonesia). Bird singing competitions must be lobbied to restrict entry to captive-sourced birds and to instigate an industry code of conduct to prevent harm to wild populations.
c.20 cm. The largest leafbird, gleaming green above and golden yellow-green below with a long hook-tipped bill. Male has a black mask enclosing the eye and a cobalt blue jawline flash. Female lacks the mask and has a paler blue jawline flash. Known for the clarity of its voice, and ready ability to incorporate other species phrases into its vocabulary, much to the species detriment at present.
Text account compilers
Fernando, E., Martin, R., Bell, F.
Contributors
Chng, S., Eaton, J., Marshall, H., Miller, A. & van Balen, B.S.
Recommended citation
BirdLife International (2024) Species factsheet: Greater Green Leafbird Chloropsis sonnerati. Downloaded from
https://datazone.birdlife.org/species/factsheet/greater-green-leafbird-chloropsis-sonnerati on 23/12/2024.
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 23/12/2024.