Biak Triller Lalage leucoptera


Justification of Red List Category
This species is listed as Near Threatened because it is suspected of having a relatively small population close to 10,000 mature individuals, all in a single subpopulation, which is inferred to be in decline due to ongoing habitat loss.

Population justification
The population is estimated to number 10,000-19,999 mature 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.

Trend justification
The population is suspected to be declining slowly as a result of ongoing habitat destruction.

Distribution and population

Lalage leucoptera is restricted to the twin islands of Biak and Supiori, in the Geelvink Bay in north West Papua, Indonesia. It is poorly known, but likely to be common in Biak's forests.


It is thought to be present in a wide range of habitats, and tolerant of secondary forest. Diet is assumed to be similar to Black-browed Triller, fruit and arthropods foraged from the mid-storey and canopy (Taylor 2016)


Forest on Biak has come under heavy pressure from logging and subsistence farming, though there have been suggestions that large-scale logging may no longer be economically feasible (Wikramanayake et al. 2002).

Conservation actions

Conservation Actions Underway
The species is assumed to be present in the 110 km2 Biak-Utara protected area, which comprises virtually impenetrable limestone areas (Wikramanayake et al. 2002).

Conservation Actions Proposed
Obtain a direct population estimate for the species. Survey to confirm its presence in the Biak-Utara protected area.


19 cm. A black and white triller similar to Black-browed but with far more extensive white in the wing, forming a continuous band from the greater coverts to the tertials.


Text account compilers
Butchart, S., Ekstrom, J. & Martin, R

Dutson, G.

Recommended citation
BirdLife International (2019) Species factsheet: Lalage leucoptera. Downloaded from http://www.birdlife.org on 17/10/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/10/2019.