In 1760 the French zoologist Mathurin Jacques Brisson included a description and an illustration of the greater ani in his Ornithologie based on a specimen collected in Cayenne, French Guiana. He used the French name Le grand Bout-de-Petun and the Latin name Crotophagus Major. Although Brisson coined Latin names, these do not conform to the binomial system and are not recognised by the International Commission on Zoological Nomenclature. The greater ani was also described and illustrated in 1779 by the French polymath Georges-Louis Leclerc, Comte de Buffon in his Histoire Naturelle des Oiseaux.
When in 1788 the German naturalist Johann Friedrich Gmelin revised and expanded Carl Linnaeus's Systema Naturae, he included the greater ani. He placed it with the smooth-billed ani in the genus Crotophaga, coined the binomial name Crotophaga major and cited the earlier authors. Gmelin specified the type locality as Cayenne. The genus name combines the Ancient Greek krotōn meaning "tick" with -phagos meaning "-eating". The species is monotypic: no subspecies are recognised.
The greater ani is about 46 cm (18 in) in length. Males weigh around 162 g (5.7 oz), females 145 g (5.1 oz). The adult is mainly blue-glossed black, with a long tail, massive ridged black bill, and a white iris. Immature birds have a brown iris.
The calls include croaking and turkey-like gobbling kro-koro.
Distribution and habitat
This ani is a breeding species from Panama and Trinidad through tropical South America to northern Argentina. It is found in mangrove swamps, semi-open woodland near water, and the edges of forests. It is a seasonal migrant in at least some parts of its range.
This is a very gregarious species, always found in noisy groups.
The nest, built and lived in communally by two to five pairs, is a deep cup lined with leaves and placed usually 2–5 m (6.6–16.4 ft) high in a tree. A number of females lay their chalky deep blue eggs in the nest and then share incubation and feeding. These breeding groups may also include non-breeding helpers. Nests have been found containing 3–10 eggs, with an incubation time of 11–12 days, with nestlings free to leave the nest after five days. They will be fed for several weeks if they choose not to leave.
In a longterm study, it was found that around 15% of females lay their eggs in the nest of another nesting group. This conspecific brood parasitism happens primarily when a female has lost her own clutch to predation. In regards to the nesting group, the first couple eggs will be rejected by other nest members when the mother of those specific egg leaves to forage. Egg rejection happens more often with larger groups, and one theory claims there is a balance within having more ani's to defend the nest from predation, and less ani's to minimize intraspecific competition. This leads to an average of two to three breeding pairs in one nest, with any greater amount being rare.
- BirdLife International (2020). "Crotophaga major". IUCN Red List of Threatened Species. 2020: e.T22684431A163883583. doi:10.2305/IUCN.UK.2020-3.RLTS.T22684431A163883583.en. Retrieved 12 November 2021.
- Brisson, Mathurin Jacques (1760). Ornithologie, ou, Méthode Contenant la Division des Oiseaux en Ordres, Sections, Genres, Especes & leurs Variétés (in French and Latin). Vol. 4. Paris: Jean-Baptiste Bauche. pp. 180–182, Plate 18 fig 2. The two stars (**) at the start of the section indicates that Brisson based his description on the examination of a specimen.
- Allen, J.A. (1910). "Collation of Brisson's genera of birds with those of Linnaeus". Bulletin of the American Museum of Natural History. 28: 317–335. hdl:2246/678.
- Buffon, Georges-Louis Leclerc de (1779). "L'Ani des Palétuviers". Histoire Naturelle des Oiseaux (in French). Vol. 6. Paris: De l'Imprimerie Royale. pp. 423–429, Plate 19.
- Buffon, Georges-Louis Leclerc de; Martinet, François-Nicolas; Daubenton, Edme-Louis; Daubenton, Louis-Jean-Marie (1765–1783). "Le grand Bout-de Petun". Planches Enluminées D'Histoire Naturelle. Vol. 2. Paris: De L'Imprimerie Royale. Plate 102, fig. 1.
- Gmelin, Johann Friedrich (1788). Systema naturae per regna tria naturae : secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis (in Latin). Vol. 1, Part 1 (13th ed.). Lipsiae [Leipzig]: Georg. Emanuel. Beer. p. 363.
- Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 123. ISBN 978-1-4081-2501-4.
- Gill, Frank; Donsker, David; Rasmussen, Pamela, eds. (January 2022). "Turacos, bustards, cuckoos, mesites, sandgrouse". IOC World Bird List Version 12.1. International Ornithologists' Union. Retrieved 12 August 2022.
- Payne, R.B. (1997). "Greater ani". In del Hoyo, J.; Elliott, A.; Sargatal, J. (eds.). Handbook of the Birds of the World. Vol. 4: Sandgrouse to Cuckoos. Barcelona, Spain: Lynx Edicions. p. 602. ISBN 978-84-87334-22-1.
- https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/documents/ogatt/Crotophaga_major%20-%20Greater%20Ani.pdf[bare URL PDF]
- Riehl, Christina; Jara, Laura (2009). "Natural history and reproductive biology of the communally breeding Greater Ani (Crotophaga major) at Gatún Lake, Panama". The Wilson Journal of Ornithology. 121 (4): 679–687. doi:10.1676/09-017.1. S2CID 9437145.
- Riehl Christina; Strong Meghan J. (2018). "Stable social relationships between unrelated females increase individual fitness in a cooperative bird". Proceedings of the Royal Society B: Biological Sciences. 285 (1876): 20180130. doi:10.1098/rspb.2018.0130. PMC 5904317. PMID 29643212.
- Meghan J. Strong; Riehl, Christina (2019). "Social parasitism as an alternative reproductive tactic in a cooperatively breeding cuckoo". Nature. 567 (7746): 96–99. Bibcode:2019Natur.567...96R. doi:10.1038/s41586-019-0981-1. PMID 30814729. S2CID 256768072.
- "Crotophaga major". Integrated Taxonomic Information System.
- Ani defined at Merriam Webster Online
- BirdLife species factsheet for Crotophaga major
- "Greater ani media". Internet Bird Collection.
- Greater Ani photo gallery at VIREO (Drexel University)
- Greater Ani species account at Neotropical Birds (Cornell Lab of Ornithology)
- "Crotophaga major". Avibase.
- Interactive range map of Crotophaga major at IUCN Red List maps
- Audio recordings of Greater Ani on Xeno-canto.