Olive Ibis Bostrychia olivacea


Justification of Red List category
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be small, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Trend justification
The overall population trend is decreasing, although some populations have unknown trends (Wetlands International 2006).


Behaviour This species is sedentary (del Hoyo et al. 1996). It breeds in solitary pairs (Brown et al. 1982) and usually forages alone, in pairs or in small flocks (del Hoyo et al. 1996) of 5-12 individuals (Brown et al. 1982), roosting at night in trees (Hancock et al. 1992). Habitat It inhabits dense lowland forest (del Hoyo et al. 1996), showing a preference for stands with little or no undergrowth and with large mature trees (Hancock et al. 1992) with dead tops for roosting in (Brown et al. 1982). It foraging in glades in open sections of forest (del Hoyo et al. 1996) and in swampy or marshy areas (Hancock et al. 1992, del Hoyo et al. 1996), also occurring along streams and rivers, in swamp-forest (del Hoyo et al. 1996), mangroves (Brown et al. 1982, del Hoyo et al. 1996), regenerating forest over abandoned plantations in Gabon (del Hoyo et al. 1996) and in montane forest up to the treeline (c.3,700 m) in Kenya and Tanzania (Hancock et al. 1992, del Hoyo et al. 1996). Diet Its diet is little known but includes adult and larval insects (e.g. beetles), worms, snails, snakes and occasionally plant matter (del Hoyo et al. 1996). Breeding site The nest is a platform of sticks constructed on a tree limb (del Hoyo et al. 1996) c.7.5 m above the ground (Brown et al. 1982). The species is also said to nest in holes in cliffs although this is unconfirmed (del Hoyo et al. 1996).



Text account compilers
Ekstrom, J., Butchart, S., Malpas, L.

Recommended citation
BirdLife International (2024) Species factsheet: Bostrychia olivacea. Downloaded from on 01/03/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from on 01/03/2024.