Justification of Red List Category
This unobtrusive species qualifies as Vulnerable because it has a small and naturally restricted range and population, which is likely to be declining owing to habitat loss at the lower fringes of its altitudinal range.
Ornithological surveys across 27 sites on nine mountains in West-Central Java between 2018 and 2020 found the species at 23 sites and 8 mountains with a mean encounter rate of 0.35 groups/hour (C. Devenish, A.R. Junaid and S. Marsden in litt. 2020). The population size is thus preliminarily estimated to fall into the band 2,500-9,999 mature individuals. This equates to 3,750-14,999 individuals in total, rounded here to 3,500-15,000 individuals.
Rates of forest loss have reduced to 1-2% (Tracewski et al. 2016, Global Forest Watch 2020) over a three-generation period (15.3 years; Bird et al. 2020) in recent years. However, due to continued habitat loss within the lower altitudinal range of the species, as well as possible effects of exploitation for the wild bird trade that may exceed declines beyond rates of forest loss alone, an on-going population reduction is inferred to be occurring at a rate of 1-9% over three generations.
Cochoa azurea is endemic to the mountain forests of west and central Java, Indonesia, where it is known from the higher peaks within a range spanning from Gunung Halimun to Gunung Merapi. There are recent records from just four localities, and at least eight mountains (C. Devenish in litt. 2020). It appears to occur at low densities, although it is perhaps more unobtrusive than genuinely rare. It is for example fairly common in Guning Masigit and Kencana (A. R. Junaid in litt. 2020). Although recent records show the occurrence of the species in southern East Java (eBird 2020), this is likely an erratic occurrence as records from Gunung Merapi National Park are believed to be the easternmost distribution of this species (A. R. Junaid in litt. 2020). Its population is nevertheless likely to be undergoing a slow decline as Javan montane forests are increasingly isolated by deforestation on lower slopes.
It inhabits montane rain forest between 900 and 3,000 m, where it is rather tame, moving quietly or sitting motionless for long periods, often in the lower and middle storeys, but also in the canopy. It is presumed to be largely sedentary, but may make local seasonal movements. It feeds on mainly fruits and berries, but will occasionally include insects and snails (Collar 2020).
Forest loss, degradation and fragmentation, through widespread agricultural encroachment and localised development (e.g. holiday resorts and geothermal projects), is becoming an increasing threat in the lower altitudinal range of the species (900 m -1,500 m). An estimated 40% forest was lost across montane West Java prior to 2000 for example (Higginbottom et al. 2019). Whilst rates of forest loss have reduced to 1-2% in recent years however (Tracewski et al. 2016, Global Forest Watch 2020) and areas above 1,500 m remain relatively secure (N. Brickle in litt. 2012), remaining forest still only covers c. 5,200 km2 of area (Higginbottom et al. 2019). It has also been recorded the domestic bird trade, albeit in very small numbers (N. Brickle in litt. 2007).
Conservation Actions Underway
It occurs in three protected areas, Gunung Gede/Pangrango National Park and Gunung Halimun Nature Reserve (now Gunung Halimun-Salak National Park), and Gunung Merapi National Park, all of which provide hope for a range of threatened species endemic to Java. The two areas cover over 500 km2 of forest between 500 m and 3,000 m. A substantial nature reserve has been proposed for Gunung Slamet (where the species remains fairly common from the southern to northern slope; A. R. Junaid in litt. 2020), and a small nature reserve exists on Gunung Tangkuban Prahu, from where there are also historical records.
23 cm. Medium-sized, thrush-like bird of forest canopy. Male has silky-blue upperparts including sides of head, wings and tail. Black underparts, iris, bill and legs. Female duller blue above and dark brown below. Immature dull blue above with brown wing-coverts, fawn below, speckled dark brown. Similar spp. Male Sunda Whistling-thrush Myophonus glaucinus generally frequents lower storey of forest, is much plumper and uniform blue. Voice Thin high-pitched whistle siiiit and more scolding cet-cet-cet in alarm. Hints Scan mid-storey and canopy of forest for occasional short flights made by this species.
Text account compilers
Benstead, P., Brickle, N., Derhé, M., Devenish, C., Gilroy, J., Junaid, A., Marsden, S. & van Balen, B.S.
BirdLife International (2022) Species factsheet: Cochoa azurea. Downloaded from http://www.birdlife.org on 30/06/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 30/06/2022.