Justification of Red List Category
This species qualifies as Vulnerable because it has a very small range, and rather strict ecological requirements that are likely to make it more sensitive to habitat loss and degradation, resulting in rapid population declines.
The population is estimated to number 2,500-9,999 individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.
Rapid population declines are suspected to be occurring in line with rates of habitat degradation, accentuated by the species's strict habitat requirements and sensitivity to environmental change.
Rhyacornis bicolor is endemic to the Philippines, where it occurs principally in the Cordillera Central and also the Sierra Madre mountains on Luzon. There are two recently discovered 1960s records from central Mindoro. Overall it is uncommon and probably declining, owing to its restricted habitat use within a limited range. Nevertheless, it appears to be locally common, with pairs separated by intervals of only 200-300 m along suitable streams on Mt Polis, and reports of it being common in Kalinga (D. Allen in litt. 2012). although evidence suggests that in some places its occurrence may be spatially and temporally patchy.
It inhabits the margins of clear, undisturbed, fast-flowing and rocky-sided mountain streams and rivers, above 300 m. Adjacent habitat includes tropical montane forest, pine forest or just scrub and scattered trees. Records from Dalton Pass, between August and December, indicate that some birds wander post-breeding.
Stream pollution and siltation caused by mining and logging are threats, as is the increasing use of agro-chemicals, all of which negatively affect water quality and prey abundance. A provincial ban on mining was recently rescinded, placing many streams at high risk from toxic pollution in the near future (D. Allen in litt. 2007). As a result, gold mining has become more widespread in recent years, along with the use of mercury in the refining process, which can lead to the pollution of watercourses. In addition to current mining activities, watercourses may also have been polluted by past mining operations (D. Allen in litt. 2012). Within Mt Pulog National Park, cultivation and clearing of forest are common, both of which are likely to cause erosion and siltation in due course. There is also increasing use of fertilisers, herbicides and pesticides by local farmers. Very few suitable, forest-flanked watercourses remain in Mt Iglit-Baco National Park (Mindoro), whilst Mt Data (Luzon) is almost devoid of forest, although some trees were preserved along streams to limit erosion. A vast proportion of Benguet province is now under intense cultivation, although forest areas with poor road access are likely to have survived (D. Allen in litt. 2007).
Conservation Actions Underway
It occurs in Balbalasang-Balbalan National Park in Kalinga, Mt Pulog National Park and the Northern Sierra Madre Natural Park on Luzon, and Mt Iglit-Baco National Park on Mindoro. There is also a recent record from the Maria Aurora Memorial National Park, which receives nominal protection.
Conservation Actions Proposed
Conduct comprehensive surveys of suitable mountain streams to clarify its range, distribution, population status and the influence of pollution / siltation on population persistence. Research its ecological requirements and seasonal movements to facilitate conservation planning. Propose further known key sites, including Mts Cetaceo and Polis for establishment as formal protected areas. Promote stricter enforcement of legislation controlling river pollution through logging, agricultural intensification and especially ore mining. Monitor water quality and habitat conditions in areas downstream of mining operations. Campaign for a ban on mining in key areas for this species.
15 cm. Small, blue-and-orange chat restricted to riparian habitats. Male has dark slaty-blue upperparts, tinged brown on wings. Deep orange-chestnut uppertail-coverts, tail, belly and vent. Dark bare parts. Female similar though duller with brownish uppertail-coverts and tail. Voice Shrill high-pitched whistles.
Text account compilers
Benstead, P., Derhé, M., Gilroy, J.
BirdLife International (2020) Species factsheet: Phoenicurus bicolor. Downloaded from http://www.birdlife.org on 15/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/08/2020.