Data Zone
Justification of Red List category
This species has been uplisted from Vulnerable because its population is estimated to be smaller than previously thought. It qualifies as Endangered because it is estimated to have a very small population, which is in decline owing to habitat loss and fragmentation.
Population justification
The population was previously estimated to number 2,500-9,999 mature individuals, based on an assessment of known records, descriptions of abundance and range size. However, the scarcity of the species has prompted this to be revised downwards to 1,000-2,499 mature individuals, equivalent to a total population of c.1,500-3,800 individuals.
Trend justification
The species is suspected to be declining at a moderate rate owing to forest clearance and degradation in its breeding grounds. Much remaining forest in the breeding strongholds of Sichuan, China, was earmarked as forest concessions for clearance in the next 20-25 years; however, a ban on logging in this area may prevent this rapid increase in logging pressure within the species's range.
Oriolus mellianus is recorded in summer from south-central Sichuan, southern Guizhou, northern Guangxi and northern Guangdong, China (BirdLife International 2001). Despite a massive increase in observer coverage of forest sites in these and adjacent areas and much higher levels of reporting than in the 1990s, no new populations have been found and populations at known sites have all declined since c.2001, such that a serious decline is apparent (R. Lewthwaite in litt. 2012). Whereas surveys in 1988 found it to be locally common in south-central Sichuan, with a notable record of a flock of 40 birds, the highest count there subsequently is 10 in June 2006 (COS 2007). One at Maolan, southern Guizhou in May 1984 remains the only summer record for the province. In Guangxi, there are no records since August 1998 when four individuals were found at Maoershan (Kadoorie Farm and Botanic Garden); the absence of records at Dayao Shan, a historically important site, is also striking. In Guangdong, peak day counts at Ba Bao Shan/Nanling NNR were 20 in 1998 and 10 (including nine males) in 2001; but the highest count since then is four in May 2007 (COS 2008, R. Lewthwaite in litt. 2012). There are also records in China of single birds on passage at Nankun Shan, southern Guangdong in August 1995, Weining, western Guizhou in September 1984 and Ningming, south-western Guanxi in October 1958; one at Ximeng, southern Yunnan on an unknown date was presumably also on passage (R. Lewthwaite in litt. 2012). It is a non-breeding visitor to southern Thailand and Cambodia. Records of wintering birds in Thailand have declined through the 1990s. An increase in ornithological surveys in Cambodia has yielded recent records from the Cardamom Mountains and Bokor (Pilgrim and Pierce 2006). Most winter records have involved males, and it may prove to be the case that females winter further north, and possibly occur in southern Myanmar (Pilgrim and Pierce 2006). Given the limited area of remaining habitat, it is likely to have a very small and declining population.
It breeds in evergreen broadleaved forest, mainly at c.600-1,700 m. In Sichuan, it was recorded in 1997 in higher densities in secondary and replanted forest than in primary forest. However, these surveys were early in the breeding season, so some records may have involved newly arrived migrants in habitats where they do not breed, and it may be easier to locate in secondary habitats. In Thailand, it frequents evergreen forest at c.600-1,300 m.
The main threat is the loss and fragmentation of forest in its breeding and wintering ranges through timber extraction, conversion to agriculture and uncontrolled fire. Many remaining areas of forest are degraded or under intense pressure. Almost all of the remaining primary forests in southern Sichuan, where it was recently recorded, were scheduled for logging, although a ban on commercial logging in this part of China since 1998 has reduced the pressure from logging in this part of its range. Hunting may also be a factor in Cambodia and in south-western Guangxi, where there is a strong bird-trapping culture (R. Lewthwaite in litt. 2012).
Conservation Actions Underway
The species is legally protected in Thailand. It has been recorded from at least seven protected areas in China and six in Thailand. Some forestry practices, such as leaving strips of primary forest along ridge-tops and replanting with native broadleaved trees, may benefit it. Surveys in southern Sichuan have improved knowledge of its distribution and ecology.
28 cm. Slim, silvery-whitish oriole with black hood and wings. Dull maroon centres to body feathers and silver fringed, dull maroon undertail-coverts and tail feathers. Similar spp. Female Maroon Oriole O. traillii has dark brown mantle and reddish-chestnut rump and pale reddish-maroon undertail-coverts.
Text account compilers
Benstead, P., Bird, J., Calvert, R., Crosby, M., Peet, N., Taylor, J., Allinson, T, Martin, R
Contributors
Francis, G., Bo, D., Dowell, S., Lewthwaite, R.
Recommended citation
BirdLife International (2024) Species factsheet: Silver Oriole Oriolus mellianus. Downloaded from
https://datazone.birdlife.org/species/factsheet/silver-oriole-oriolus-mellianus on 23/11/2024.
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 23/11/2024.