Threskiornis aethiopicus | Sacred Ibis | íbis bheannaithe
Regulated invasive species of Union concern under the European Regulation on the prevention and management of the introduction and spread of invasive alien species [1143/2014].
Invasive species - risk of High Impact
Introduction pathways - 1
Escape from Confinement
Introduction pathways subclass - 1
Introduction pathways - 2
Introduction pathways subclass - 2
Natural dispersal across borders of invasive aliens
NAPRA Ireland risk assessed
Large (90cm) white bird with bald, black head and neck. Long downward curving black bill, black legs and black wing tips and plumes. Males and females are similar colours (NNSS, undated) but females are smaller, particularly the bill (Robert et al., 2013). Juveniles necks are feathered and the wing tips are brownish (Yèsou & Clergeau, 2005).
A highly adaptable, opportunistic omnivore, this long-lived bird (up to 20 years; Robert et al., 2013) eats eggs, nestlings, amphibians (Brochier et al., 2010), invertebrates (including molluscs and crustaceans), small mammals, carrion, offal, spiders, reptiles, fish and refuse (Robert et al., 2013). Feed in meadows, marshes, ploughed fields, lakes, seashores, rubbish dumps, farmyards and even slurry pits (Yèsou & Clergeau, 2005). Capable of increasing populations quickly and the population in western France has increased from a single source to over 5000 birds in 30 years (Brochier et al., 2010). Their predatory feeding habits and large numbers can have heavy impacts on native birds (particularly those ground nesting in colonies) and amphibian species (European Commission, 2017). May also compete with native species for nest sites (NNSS, undated). Perhaps their biggest impact is at roost sites, where over 1000 birds may roost (Yèsou & Clergeau, 2005). They trample vegetation and create a thick layer of droppings which destroys grasses, shrubs and trees (Robert et al., 2013). May become a social nuisance by scavenging from dustbins near homesteads (Yèsou & Clergeau, 2005). Can cause a bird-strike hazard to aircraft (NNSS, 2011). Indeed, Kumschick & Nentwig (2010) developed a scoring system of the environmental and economic impact of alien species. Threskiornis aethiopicus scored as highly as some of the worst mammals.
The breeding season extends from March to May (NNSS, undated). Threskiornis aethiopicus is a colonial breeder. The male collects the nest material, usually sticks and grass and the female builds the nest in the branches of a tree (Robert et al.,2013) usually but also in low scrub or even on the ground (Wright, 2011). Two to four eggs are laid, which are white with a blue tinge (NNSS, undated). Both males and females incubate the eggs and feed the chicks once hatched. (Robert et al., 2013). The hatched chicks often form large crèches (NNSS, undated).
Pathway and vector description
In the 1970's flocks of free flying birds were bred in zoos and inevitably some escaped establishing populations in France, Spain, Italy and the Canary Islands (Yèsou & Clergeau, 2005). Dispersal from there is via natural spread and this highly mobile bird can travel several hundred kilometers (Yèsou & Clergeau, 2005). The closest breeding population to Ireland is in Western France (Wright, 2011).
Mechanism of impact
Competition, Predation, Trampling
There is currently an EU wide ban on the sale of this species and personal and zoo ownership is being phased out (European Commission, 2017).
This species is highly visible and readily detected at early stages of invasion (Robert et al., 2013). Prevention is the most effective method of control and the pinioning of all captive birds should help to prevent further invasions (Robert et al., 2013).
Control is generally by a combination of shooting flying birds, usually at roost sites and feeding grounds (Brochier et al., 2010) and egg oiling, which serves to prevent the hatching of eggs (Robert et al., 2013).
Meadows, marshes, reedbeds, often near the coast and rubbish dumps (Yèsou & Clergeau, 2005). Being near water seems to be a requirement (Robert et al., 2013).
Introduced in Europe (Belgium, France, Greece, Italy, Latvia, Lithuania, Portugal, Spain; European Commission, 2017), the Arabian peninsula, Chinese Taipei and Florida (Brochier et al., 2010).
Sub-Saharan Africa (European Commission, 2017).
Records submitted to Data Centre in 2021
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How can you help
Report any sightings to the National Biodiversity Data Centre.
Brochier, B., Vangeluwe, D. & van den Berg, T. (2010) Alien Invasive Birds. Revue scientifique et technique (International Office of Epizootics) , 2010, 29(2): 217-226 http://www.unitheque.com/UploadFile/DocumentPDF/E/S/LFYD-9789290447818.pdf Site accessed 20 October 2017.
European Commission. (2017). Invasive Alien Species of Union Concern. European Union, Luxembourg.
GB Non-native Species Secretariat (NNSS). (undated). Species Description – Sacred ibis. Identification sheet. http://www.nonnativespecies.org/search.cfm Site accessed 20 October 2017.
Kumschick, S. & Nentwig, W. (2010) Some alien birds have as severe an impact as the most effectual alien mammals in Europe. Biological Conservation 143: 2757–2762 ftp://ieeservftp01.unibe.ch/pub/iee/groups/syn/publications/pdfs/2010/KumschickNentwigalienbirdsBiolCons2010.pdf Site accessed 20 October 2017.
Marchant, J. (2012) Sacred ibis, Threskiornis aethiopicus. Factsheet. Non-native Species Secretariat (NNSS). http://www.nonnativespecies.org/factsheet/downloadFactsheet.cfm?speciesId=3537 Site accessed 20 October 2017.
Robert, H., Lafontaine, R.-M., Delsinne, T., Beudels-Jamar, R.C. (2013). Risk analysis of the Sacred Ibis Threskiornis aethiopicus (Latham 1790). - Risk analysis report of non-native organisms in Belgium from the Royal Belgian Institute of Natural Sciences for the Federal Public Service Health, Food chain safety and Environment. 35 p. http://ias.biodiversity.be/species/risk Site accessed 20 October 2017.
Williams, A.J. & Ward, V.J. (2006) Sacred Ibis and Gray Heron Predation of Cape Cormorant Eggs and Chicks; and a Review of Ciconiiform Birds as Seabird Predators. Waterbirds 29(3): 321-327 http://cescos.fau.edu/gawliklab/papers/WilliamsAJandVLWard2006.pdf Site accessed 20 October 2017.
Wright, L. (2011). GB Non-native Organism Risk Assessment for Threskiornis aethiopicus. http://www.nonnativespecies.org/index.cfm?pageid=143 Site accessed 20 October 2017.
Yésou, P. & Clergeau, P. 2005 Sacred Ibis: a new invasive species in Europe. Birding World 18 (12): 517-526. http://birdingworld.co.uk/images/SacredIbises.pdf Site accessed 20 October 2017.
The ‘Delivering Alien Invasive Species Inventories for Europe’ project has listed Sacred Ibis (Threskiornis aethiopicus) as one of the 100 worst invasive species in Europe.