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Dwarf Bittern Ixobrychus sturmii

Justification
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.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
Dowsett, R. J.; Forbes-Watson, A. D. 1993. Checklist of birds of the Afrotropical and Malagasy regions. Tauraco Press, Li
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Synonym(s)
Ardeirallus sturmii Cramp and Simmons (1977-1994), Ardeirallus sturmii sturmii Cramp and Simmons (1977-1994)

Trend justification
The population trend is difficult to determine because of uncertainty over the extent of threats to the species.

Ecology
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).

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

References
del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.

Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.

Hancock, J.; Kushlan, J. 1984. The herons handbook. Croom Helm, London.

Kushlan, J. A.; Hancock, J. A. 2005. The herons. Oxford University Press, Oxford, U.K.

Nikolaus, G. 2001. Bird exploitation for traditional medicine in Nigeria. Malimbus 23: 45-55.

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

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Ixobrychus sturmii. Downloaded from http://www.birdlife.org on 21/04/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/04/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Least Concern
Family Ardeidae (Herons and egrets)
Species name author (Wagler, 1827)
Population size mature individuals
Population trend Unknown
Distribution size (breeding/resident) 12,900,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- Climate change species distributions