Justification of Red List Category
This species is listed as Near Threatened on the basis that projected rates of forest loss in its range are suspected to be driving a moderately rapid population decline.
The global population size has not been quantified, but the species is reported to be relatively numerous in forest on Halmahera (Madge and Burn 1993). A survey of Aketajawe-Lolobata National Park, Halmahera, gave a potential population estimate of c.44,000 individuals (H. Bashari in lit. 2016), but it is not certain if this is an estimated population for just Halamhera, or if it represents a global population estimate, and so this estimate is not currently used.
A recent study by Vetter (2009) used remote sensing techniques to track the rate and spatial pattern of forest loss in the North Maluku Endemic Bird Area between 1990 and 2003, and project rates of deforestation over the next three generations for restricted range bird species found in this region. This study estimated the rate of forest loss within the geographic and elevation range of this species to be c.20.3% between 1990 and 2003, and projected the loss of c.37% of forest in its range over the next three generations (estimated to be c.22 years) (Vetter 2009). However, the species shows an apparent tolerance of modified habitats, which would be expected to buffer its population against the loss of primary habitat to some extent. Based on this, the species is suspected to be undergoing a decline of 25-29% over three generations, from 2004 until 2026.
Corvus validus is found on the islands of Morotai, Halmahera, Kayoa, Kasiruta, Bacan and Obi, Indonesia (del Hoyo et al. 2009); although surveys on Obi in 2012 failed to find this species and interviews with local residents showed this species was unfamiliar to them (Mittermeier et al. 2013).
The species mainly inhabits primary forest and is locally found in secondary and partially logged forest, and has been recorded in agricultural areas, including plantations, grassland with trees, and in settlements on Halmahera (del Hoyo et al. 2009, H. Bashari in litt. 2016). On Halmahera it may be found from sea level to 1,100 m (H. Bashari in litt. 2016).
The primary threat to the species is habitat loss through commercial logging for timber, and clearance for shifting agriculture, mining, settlements and plantations of oil palm, coffee, rubber, coconut, clove, nutmeg and timber species (Vetter 2009, Burung Indonesia in litt. 2014, H. Bashari in litt. 2016). Another potential threat is posed by wildfires, which have devastated areas on other Indonesian islands, with the chances of such fires being increased by the conversion of forest to scrub and grassland and the opening up of forests for road construction, as well as selective logging and fragmentation (Vetter 2009).
Conservation Actions Underway
There are no targeted conservation actions known for this species, but it does occur in Aketajawe-Lolobata National Park (H. Bashari in litt. 2016).
Conservation Actions Proposed
Carry out surveys to assess the species's population size. Conduct regular surveys to monitor the population trend. Track rates of habitat loss through regular studies of satellite images. Increase the area of suitable habitat with protected status.
Text account compilers
Symes, A., Ekstrom, J., Butchart, S., Wheatley, H., Taylor, J., Westrip, J.
Mittermeier, J., Bashari, B., Burung Indonesia
BirdLife International (2020) Species factsheet: Corvus validus. Downloaded from http://www.birdlife.org on 08/04/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 08/04/2020.