Justification of Red List Category
This species has a very small population size as a consequence of widespread reductions in the extent and quality of forest within its range in the past. This qualifies it as Vulnerable.
While the population size had previously been estimated to fall in the band 2,500-9,999 mature individuals, the scarcity and patchiness of records suggest that the population size of this species may in fact be far smaller (S. Mahood in litt. 2013, R. Hutchinson in litt. 2016, A. Dwarshuis in litt. 2016). It is highly plausible that the population size may be <2,500 mature individuals, and could be placed in the range 1,000-2,499 mature individuals, equating roughly to 1,500-3,750 individuals in total.
Lowland forests in the Philippines have been largely deforested in the past, and remaining fragments remain under intense pressure from illegal logging, conversion to wood-pulp plantations and agriculture, and logging and mining concessions. Yet, much of the habitat loss within the species's range occurred >3 generations ago. A reassessment of habitat loss (Tracewski et al. 2016) suggests that the current rate of decline may be lower than 5% over three generations. However, it has been suggested that the population size of this species numbers less than 2,500 mature individuals (S. Mahood in litt. 2013, R. Hutchinson in litt. 2016, A. Dwarshuis in litt. 2016).
Hypothymis coelestis is endemic to the Philippines. Most recent records come from Mindanao (R. Hutchinson in litt. 2016), but there have been records also from Luzon, Negros, Sibuyan, Samar, Dinagat, Basilan and Tawitawi (Collar et al. 1999, B. Tabaranza in litt. 2007). Early collectors in the region considered the species to be rare, though in 1959 it was reportedly commoner on Basilan and Sibuyan than it was on Negros. Now, however, the subspecies rabori, which is endemic to the Visayas, is likely to be extinct (it has not been recorded on Negros since 1959 and was not found in searches of Sibuyan in the early 1990s or subsequently [del Hoyo et al. 2006]), and the species may have been disappeared from Basilan too. The majority of recent records come from near Bislig, in the PICOP forest, on Mindanao, with only scattered records from elsewhere (R. Hutchinson in litt. 2016, eBird 2017). A considerable decline is likely, although its apparent patchy distribution and the ease with which it may be overlooked, suggest that it may be less rare than available evidence suggests.
It inhabits the canopy and middle storeys of lowland forest, forest edge and secondary growth up to 750 m, although usually much lower. It has been postulated that it may be a riverine specialist, particularly in areas with a marked dry season, which could account for its seemingly patchy distribution. However, whilst this is possibly the case on Luzon, it is not true on Mindanao (R. Hutchinson in litt. 2012).
Widespread, continuing deforestation, particularly in the lowlands, had reduced original forest cover to an estimated 4% of its original on Negros by the late 1980s, to 29% on Mindanao and to 24% on Luzon (where forest cover in the Sierra Madre has declined by 83% since the 1930s; and areas where the species was abundant in 2003 has since been completely deforested [R. Hutchinson in litt. 2016]). Much of the remaining lowland forest is currently under logging concessions or consideration for mining applications. Habitat is also threatened by illegal logging and road development plans in the Sierra Madre. Forest at Bislig, the site of the only recent records on Mindanao, was widely cleared under concession and planted with exotic trees for paper production. Since the paper operation finished in 2005, the area has been overrun by illegal settlers and loggers (D. Allen in litt. 2012, R. Hutchinson in litt. 2012). Remaining beach forest on Mantibuan, Tawitawi where it may have been recorded in 2007 is threatened by plantations for cassava, coconut and banana (B. Tabaranza in litt. 2007). There is little remaining forest elsewhere on Tawitawi.
Conservation Actions Underway
It has been recently recorded in one protected area, the Northern Sierra Madre Natural Park, and two further sites proposed for conservation funding, on Tawitawi and Dinagat, where a three-year community resource management programme began in 1996.
18 cm. Slim, electric-blue, canopy-dwelling flycatcher. Entire plumage dark vivid sky-blue, washed lilac on cheeks and throat. Duller grey-blue on belly. Narrow yellowish eye-ring. Elongated, paler electric-blue crown feathers form droopy crest which usually lies flat, only raised when excited. Female similar although slightly duller. Similar spp. Black-naped Monarch H. azurea and Short-crested Monarch H. helenae differ in black facial markings and generally show less of a crest. Voice Distinctive, fast, high-pitched tee-tee-tee and typical rasping alarm call. Hints Joins mixed feeding flocks. Tends to stay mostly in canopy.
Text account compilers
Peet, N., Taylor, J., Westrip, J., Benstead, P., Allinson, T, Davidson, P., Hermes, C., Khwaja, N., Bird, J., Lowen, J., Martin, R.
Tabaranza, B., Mahood, S., Dwarshuis, A., Allen, D., Hutchinson, R.
BirdLife International (2022) Species factsheet: Hypothymis coelestis. Downloaded from http://www.birdlife.org on 01/12/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 01/12/2022.