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Glossy Ibis Plegadis falcinellus

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 extremely 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#.
Christidis, L.; Boles, W. E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia.
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.
SACC. 2006. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.html#.
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

Trend justification
The overall population trend is decreasing, although some populations have unknown trends (Wetlands International 2006). This species has undergone a large and statistically significant increase over the last 40 years in North America (3800% increase over 40 years, equating to a 150% increase per decade; data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007) Note, however, that these surveys cover less than 50% of the species's range in North America.

Ecology
Behaviour All populations of this species undergo post-breeding dispersal movements (del Hoyo et al. 1992) and are considerably nomadic (Snow and Perrins 1998). In addition northern breeding populations are fully migratory (del Hoyo et al. 1992) and may travel on a broad front (e.g. across the Sahara) (Brown et al. 1982). Northern and southern breeding populations breed during the local spring, whilst breeding elsewhere coincides with the rains (del Hoyo et al. 1992). The species nests in mixed-species colonies, either in small groups (e.g. 5-100 pairs in Africa) (Brown et al. 1982) or in large aggregations of thousands of pairs, and during the winter or dry seasons the species usually forages in small flocks (Hancock et al. 1992, del Hoyo et al. 1992) of up to 30 indivduals (Brown et al. 1982). It often roosts communally at night in large groups (sometimes thousands of individuals) with other species, occasionally in trees far from wetland feeding sites (Brown et al. 1982). Habitat The species feeds in very shallow water (Hancock et al. 1992) and nests in freshwater or brackish wetlands with tall dense stands of emergent vegetation (e.g. reeds or rushes) and low trees or bushes (Marchant and Higgins 1990, del Hoyo et al. 1992). It shows a preference for marshes at the edges of lakes and rivers (Hancock et al. 1992), as well as lagoons, flood-plains, wet meadows (Marchant and Higgins 1990, del Hoyo et al. 1992), swamps (del Hoyo et al. 1992), reservoirs (Hancock et al. 1992), sewage ponds, rice-fields and irrigated cultivation (Marchant and Higgins 1990, del Hoyo et al. 1992). It less often occurs in coastal locations such as estuaries, deltas, saltmarshes (Hancock et al. 1992) and coastal lagoons (del Hoyo et al. 1992). Roosting sites are often large trees that may be far from water (Brown et al. 1982, del Hoyo et al. 1992). Diet The diet of the species varies seasonally depending on what is available (Hancock et al. 1992). It takes adult and larval insects (e.g. aquatic beetles, dragonflies, grasshoppers, crickets, flies and caddisflies), worms, leeches, molluscs (e.g. snails and mussels), crustaceans (e.g. crabs and crayfish) and occasionally fish, frogs, tadpoles, lizards, small snakes and nestling birds (del Hoyo et al. 1992). Breeding site The nest is a platform of twigs and vegetation usually positioned less than 1 m above water (occasionally up to 7 m) in tall dense stands of emergent vegetation (e.g. reeds or rushes), low trees or bushes over water (del Hoyo et al. 1992).

Threats
The species is threatened by wetland habitat degradation and loss (del Hoyo et al. 1992, Snow and Perrins 1998) through drainage (Marchant and Higgins 1990, Hancock et al. 1992) for irrigation and hydroelectric power production (Balian et al. 2002), clearing, grazing, burning, increased salinity, groundwater extraction and invasion by exotic plants (Marchant and Higgins 1990). It is also threatened locally by hunting (del Hoyo et al. 1992, Snow and Perrins 1998), disturbance and pesticides (del Hoyo et al. 1992), and is susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006).

Related state of the world's birds case studies

References
Balian, L. V.; Ghasabian, M. G.; Adamian, M. S.; Klem Jr, D. 2002. Changes in the waterbird community of the Lake Sevan-Lake Gilli area, Republic of Armenia: a case for restoration. Biological Conservation 106(2): 157-163.

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.

Marchant, S.; Higgins, P. J. 1990. Handbook of Australian, New Zealand and Antarctic birds, 1: ratites to ducks. Oxford University Press, Melbourne.

Melville, D. S.; Shortridge, K. F. 2006. Migratory waterbirds and avian influenza in the East Asian-Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK.

Snow, D. W.; Perrins, C. M. 1998. The Birds of the Western Palearctic vol. 1: Non-Passerines. Oxford University Press, Oxford.

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

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

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: Plegadis falcinellus. Downloaded from http://www.birdlife.org on 21/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/12/2014.

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 - Glossy ibis (Plegadis falcinellus) 0

Key facts
Current IUCN Red List category Least Concern
Family Threskiornithidae (Ibises, Spoonbills)
Species name author (Linnaeus, 1766)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 19,400,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- Projected distributions under climate change