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LC
Squacco Heron Ardeola ralloides

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). 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 is very large, and hence does not 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.

Trend justification
The overall population trend is decreasing, although some populations may be stable or increasing, and others have unknown trends (Wetlands International 2006).

Ecology
Behaviour In the Palearctic this species is migratory and dispersive (del Hoyo et al. 1992), travelling on a broad front between breeding and wintering areas (Kushlan and Hancock 2005). African breeding populations are nomadic or sedentary however and make local dispersive movements to temporary wetlands following seasonal rains (Hockey et al. 2005). The species breeds from April to July in Eurasia and North Africa (the populations south of the Sahara breeding mainly during the rainy season) (del Hoyo et al. 1992) in single- or mixed-species colonies that can be up to 2,000 pairs in size (del Hoyo et al. 1992). After breeding Palearctic populations migrate south from August to November (del Hoyo et al. 1992, Kushlan and Hancock 2005), returning to the breeding colonies between February and May (Kushlan and Hancock 2005). The species feeds solitarily (Kushlan and Hancock 2005) or in small groups of 2-5 individuals during the breeding season (Kushlan and Hancock 2005) although in winter and on migration large feeding flocks may form (Kushlan and Hancock 2005) and in Africa resident populations may feed in parties of up to 20 individuals (Brown et al. 1982). The species is mainly crepuscular (del Hoyo et al. 1992), roosting by day and night in large (Kushlan and Hancock 2005) often mixed-species (Brown et al. 1982) groups in sheltered woods and reedbeds (these roosts may draw in herons feeding up to 80 km away) (Kushlan and Hancock 2005). Habitat The species inhabits permanent or temporary wetlands (Brown et al. 1982) showing a preference for fresh waters with abundant marsh vegetation (del Hoyo et al. 1992), reedbeds, nearby bushes, trees and scrub (Kushlan and Hancock 2005). Habitats frequented include swampy plains, river valleys, deltas, lakes, ponds, canals and ditches (del Hoyo et al. 1992) although rice paddyfields (del Hoyo et al. 1992, Kushlan and Hancock 2005) are now the principle habitat throughout much of its range (Kushlan and Hancock 2005). On migration (Kushlan and Hancock 2005) the species may also occur on estuaries, inshore reefs or islets (del Hoyo et al. 1992). It generally avoids dry habitats and those with very high rainfall (Kushlan and Hancock 2005), and usually breeds in the lowlands although it has bred on montane lakes up to 2,000 m (del Hoyo et al. 1992). Diet Its diet consists predominantly of larval insects although fish and amphibians (del Hoyo et al. 1992) (e.g. frogs and tadpoles) (Kushlan and Hancock 2005) up to 10 cm long, grasshoppers, beetles, butterflies, spiders, crustaceans, molluscs and exceptionally small birds may also be taken (del Hoyo et al. 1992). Breeding site The nest is a well-constructed platform (del Hoyo et al. 1992) usually placed less than 2 m (occasionally up to 20 m) high near or over water in reedbeds (del Hoyo et al. 1992) or in dense thickets of trees or shrubs (Kushlan and Hancock 2005) (e.g. of willow Salix spp. or poplar Populus spp.) (Hafner and Didner 1997), preferring nesting sites within 5 km of feeding areas (Kushlan and Hancock 2005). The species breeds in single- or mixed-species colonies that can be up to 2,000 pairs in size (del Hoyo et al. 1992), neighbouring pairs building nests 5-10 m apart (occasionally as close as 0.5 m) (Kushlan and Hancock 2005).

Threats
The greatest threat to this species is the loss and deterioration of natural and man-made freshwater habitats (e.g. through changes to flood regimes in rice paddyfields) and wet woodlands (e.g. through woodcutting and burning) (Hafner and Didner 1997). Utilisation The species is hunted and traded at traditional medicine markets in Nigeria (Nikolaus 2001).

Related state of the world's birds case studies

References
Brown, L. H.; Urban, E. K.; Newman, K. 1982. The birds of Africa vol I. Academic Press, London.

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.

Hafner, H.; Didner, E. 1997. Ardeola ralloides Squacco Heron. Birds of the Western Palearctic Update 1: 166-174.

Hockey, P. A. R.; Dean, W. R. J.; Ryan, P. G. 2005. Roberts birds of southern Africa. Trustees of the John Voelcker Bird Book Fund, Cape Town, South Africa.

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.

Further web sources of information
Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

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

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

Recommended citation
BirdLife International (2014) Species factsheet: Ardeola ralloides. Downloaded from http://www.birdlife.org on 20/04/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/04/2014.

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.

Additional resources for this species

ARKive species - Squacco heron (Ardeola ralloides) 0

Key facts
Current IUCN Red List category Least Concern
Family Ardeidae (Herons and egrets)
Species name author (Scopoli, 1769)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 18,600,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- Climate change species distributions