Dwarf Bittern Ixobrychus sturmii


Justification of Red List Category
This species has an extremely 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). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, 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 population trend is difficult to determine because of uncertainty over the extent of threats to the species.


Behaviour This species is an intra-African migrant, its movements related to changes in water level due to seasonal rainfall (del Hoyo et al. 1992). The breeding season is geographically variable but generally coincides with the rains (although the species may also breed early in the dry season) (Kushlan and Hancock 2005). It breeds solitarily or in small groups of a few dozen pairs, and hunts nocturnally alone or in pairs, sometimes also hunting by day if conditions are cloudy (del Hoyo et al. 1992). Habitat It uses a variety of habitats, but shows a preference for thickets and forests characterised by fluctuating water levels (Kushlan and Hancock 2005). It frequents the margins of freshwater rivers, streams, lakes, reservoirs, ponds and pools overhung with dense foliage (Kushlan and Hancock 2005), marshes with grasses or reeds, seasonally flooded areas, mangroves (Hancock and Kushlan 1984, del Hoyo et al. 1992), rice-fields, and open grassy swamps with bulrushes or papyrus (del Hoyo et al. 1992, Kushlan and Hancock 2005). Diet Its diet consists predominantly of grasshoppers and frogs, but it will also take water beetles, small fish, crabs, spiders and snails (Hancock and Kushlan 1984, del Hoyo et al. 1992, Kushlan and Hancock 2005). Breeding site The nest is a stick platform positioned 0.5-4 m high (Kushlan and Hancock 2005) on horizontal or hanging branches of trees and bushes (del Hoyo et al. 1992) that overhang water or stand in flooded areas (Hancock and Kushlan 1984).


Utilisation The species is hunted and traded at traditional medicine markets in Nigeria (Nikolaus 2001).


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

Recommended citation
BirdLife International (2020) Species factsheet: Ixobrychus sturmii. Downloaded from on 13/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from on 13/08/2020.