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Yellow-billed Stork Mycteria ibis

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.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

Trend justification
The overall trend is decreasing, although some populations may be stable (Wetlands International 2006).

Ecology
Behaviour This species makes irregular migratory, partially migratory or nomadic movements within Africa (del Hoyo et al. 1992, Hockey et al. 2005) to areas where changing water levels increase fish availability (Hockey et al. 2005). Some populations are also largely sedentary (del Hoyo et al. 1992). Breeding is seasonal and starts whenever food is most abundant according to local ecological conditions (e.g. when fish become concentrated in small wetlands or marshes [Hancock et al. 1992]), this may either be towards the end of the rains or during the dry season (del Hoyo et al. 1992). The species breeds colonially, often with other species (Brown et al. 1982, del Hoyo et al. 1992), usually in small groups of 10-20 pairs (Brown et al. 1982) (exceptionally as many as 50 pairs [Hancock et al. 1992]). It is a gregarious species but never aggregates into very large flocks (Brown et al. 1982), being more often observed in pairs or small flocks of up to 50 individuals (Hockey et al. 2005). At night it forms communal roosts in favoured roosting sites (e.g. sandbanks or trees), which may attract individuals from a wide area (Brown et al. 1982). Habitat The species inhabits a variety of wetlands (del Hoyo et al. 1992) with shallow water 10-40 cm deep for feeding (Hancock et al. 1992) and sandbanks or trees for roosting (del Hoyo et al. 1992). It frequents large swamps, the margins of rivers and lakes, lagoons (del Hoyo et al. 1992), large marshes, small pools (Hancock et al. 1992), flooded grassland (Hockey et al. 2005), alkaline lakes, reservoirs, waterholes and rice-paddies (del Hoyo et al. 1992), less commonly foraging on marine mudflats (del Hoyo et al. 1992), in tidal pools along beaches (Hancock et al. 1992) or in estuaries (Hockey et al. 2005). The species generally avoids areas of large-scale flooding and is rare in forested areas (although it may occur in wooded savanna [del Hoyo et al. 1992]). Diet Its diet consists of small aquatic prey such as frogs, small fish (del Hoyo et al. 1992), aquatic insects, worms, crustaceans and occasionally small mammals and birds (Hancock et al. 1992). Breeding site The nest is constructed of sticks (del Hoyo et al. 1992) and is positioned in small trees over water or high up in larger trees on dry land (Hancock et al. 1992) (e.g. Accacia spp., Bombax spp. [del Hoyo et al. 1992] or baobabs [Brown et al. 1982]). The species nests colonially in single- or mixed-species groups (del Hoyo et al. 1992) with up to 10-20 pairs per tree (Brown et al. 1982) (occasionally up to 50 pairs [Hancock et al. 1992]), neighbouring nests usually spaced 1-3 m apart (Hockey et al. 2005).

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.

Hancock, J. A.; Kushlan, J. A.; Kahl, M. P. 1992. Storks, ibises and spoonbills of the world. Academic Press, London.

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.

Further web sources of information
Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

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

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

Recommended citation
BirdLife International (2014) Species factsheet: Mycteria ibis. Downloaded from http://www.birdlife.org on 27/08/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/08/2014.

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 - Yellow-billed stork (Mycteria ibis) 0

Key facts
Current IUCN Red List category Least Concern
Family Ciconiidae (Storks)
Species name author (Linnaeus, 1766)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 18,100,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- Projected distributions under climate change