Justification of Red List Category
Survey work has judged this species to have an extremely small population which, given the reported continuation of habitat loss on the one island where it occurs, results in its classification as Critically Endangered.
The population is estimated to number 100-200 individuals, roughly equating to 70-130 mature individuals.
Forest loss has reportedly decimated the ecology of Boano island. Continuing encroachment is likely to be driving a moderate and on-going decline in this species.
This species is confined to the island of Boano off north-west Seram, South Maluku, Indonesia, where it appears to occupy a very limited area (probably no more than 20%) of the mountainous part (c.70 km2) of the island (BirdLife International 2001). Known from just one specimen collected at an unspecified locality in 1918, it was rediscovered in 1991, in a foothill gorge of Gunung Tahun. Observations at the same locality in 1994 led to an estimate of 5-10 birds in a 5 ha patch of forest. Based on the extent of suitable habitat this was extrapolated to give a population estimate of 100-200 individuals (Moeliker and Heij 1995). The first record since 1994 came in 2011, when at least 12 individuals were seen and around 20 more were heard in an area of cut-over forest where none had been seen on the 1994 expedition (Eaton 2011), and there have been several reports of the species over recent years (see eBird 2018).
It is presumably a sedentary resident, and is believed to be restricted to the higher parts of the island (c.150-700 m), although recent observations come from dense secondary semi-evergreen forest, comprising trees up to 20 m high, in a gorge between 150 m and 200 m. Foraging was noted low (generally below 2 m) in lush undergrowth consisting mainly of Ficus and Coffea spp. and thickets of bamboo (Dendrocalamus spp.). Individuals are also associated with mixed-species flocks in the lower-middle storeys.
Forests on the island of Boano have long been exploited for human needs. Although recent cutting is deemed to have irreversibly affected the island's ecosystem, patches of valley-bottom forest remain wherein the monarch persists. However, its extremely low estimated population size, and the apparent ease with which forest at the single known site could be cleared or burnt, renders it highly vulnerable to extinction.
Conservation Actions Underway
No targeted measures have been taken, other than the survey to relocate the species in the early 1990s.
16 cm. Strikingly patterned flycatcher. Black above, including sides of head, with a variable small white mark or bar on forecrown and white outer tail feathers. Black chin, rest of underparts white, including cheeks. Similar spp. Slaty Flycatcher Myiagra galeata has no black on chin and no white in tail. Voice Clear tjuuu-tjuuu, immediately followed by a soft, buzzing trill that fades out after c.6 seconds.
Text account compilers
Taylor, J., Tobias, J., Westrip, J., Bird, J., Davidson, P., Mahood, S., Benstead, P., Symes, A.
Eaton, J. & Moeliker, C.W.
BirdLife International (2020) Species factsheet: Symposiachrus boanensis. Downloaded from http://www.birdlife.org on 29/10/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 29/10/2020.