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Anhinga (Darter) (Anhinga anhinga)
Anhinga Americana
By Petr Myska -July 2008

Anhingas, sometimes called Darters are quite unique birds. Starting with the fact that the whole family Anhingidae (Darters) has just one genus (Anhinga) with only one species (Anhinga anhinga)*. At first sight Anhinga resembles a large cormorant with extremely long neck. In fact, it is a relative of cormorants, differences, however abound.

Anhinga, unlike other water birds does not posses completely waterproof feathers. That in effect means that its body is much less buoyant than cormorant’s for example. While swimming, only the neck and the head of the bird show above the water surface. This makes anhinga an excellent diver and although it is not particularly fast swimmer, it is an effective under water hunter. Its pray is mostly fish, but its diet includes also aquatic invertebrates, amphibians and small aquatic reptiles (Owre 1967).

However, its absorbent feathers come with a price. Anhingas lose body heat quite quickly when under water due to the lack of insulating layer of dry feathers. After each hunt, they need to find a suitable perch and spread their soaked wings in the sun. The distribution of the species is therefore limited to warmer and sunnier latitudes (del Hoyo et al. 1992, Henneman 1985). Anhingas would suffer from hypothermia and die in places, where cormorants thrive. Experts underwater, anhingas can also soar, something cormorants cannot do.

This species can be found from SE USA south to Ecuador and N Argentina. In Mexico it breeds locally on both slopes from Sinaloa and Tamaulipas south, including Yucatan peninsula (Howel and Webb, 1995). Anhingas are residents to the Banderas Bay area and although not seen too frequently, they can be spotted with some luck perching close to fresh water sources.

* Some authors recognize more than one species worldwide.

Visit the VN Illustrated Database of Mexican Biodiversity - http://www.vivanatura.org/
Visit the Images of Nature - http://www.imanat.com/

Petr Myska E-mail: pmyska@vivanatura.org

Bibliography:
• Del Hoyo, J., A. Elliot, J. Sargatal. 1992. Handbook of the Birds of the World. Vol. 1, Ostrich to Ducks.. Barcelona: Lynx Editions.
• Hennemann, W. 1985. Energetics behavior and the zoogeography of *Anhinga anhinga* and double-crested cormorants *Phalacrocorax auritus*. Ornis Scand., 16(4): 319-323.
• Howell N.G.S and Webb S. 1995: A Guide to the Birds of Mexico and Northern Central America, Oxford University Press. New York USA.
• Owre, O. 1967. Adaptations for locomotion and feeding in the Anhinga and the Double-crested Cormorant. Ornithological Monographs, 6: 138-276.

Recommended reading online:
http://www.vivanatura.org/Anhinga%20anhinga.html
http://animaldiversity.ummz.umich.edu/site/accounts/information/Anhinga_anhinga.html
http://en.wikipedia.org/wiki/Anhinga