Anhinga

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Anhinga
Female Anhinga drying its feathers, Costa Rica
Female Anhinga drying its feathers, Costa Rica
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Pelecaniformes
Family: Anhingidae
Genus: Anhinga
Species: A. anhinga
Binomial name
Anhinga anhinga
(Linnaeus, 1766)
For the bird genus Anhinga, see Darter

The Anhinga (Anhinga anhinga), sometimes called Snakebird, Darter, American Darter, or Water Turkey, is a water bird of the warmer parts of North America and South America. The word "anhinga" comes from the Brazilian Tupi language and means devil bird or snake bird.

It is a cormorant-like bird with an average body length of 85 cm (35 in), a wingspan of 117 cm (45 in), and a weight of 1,350 g. It is a dark-plumaged fish-eater with a very long neck, and often swims with only the neck above water. When swimming in this style the name Snakebird is apparent, since only the colored neck appears above water the bird looks like a snake ready to strike.

The Anhinga is a member of the darter family, Anhingidae, and is closely related to Indian (Anhinga melanogaster), African (Anhinga rufa), and Australian (Anhinga novaehollandiae) Darters.

The Anhinga's feathers are not waterproofed by oils like those of ducks, and can get waterlogged, causing the bird to become barely buoyant. However, this allows it to dive easily and search for fish under the water. It can stay down for significant periods.

When necessary, the Anhinga will dry out its wings and feathers. It will perch for long periods with its wings spread to allow the drying process, as do cormorants. If it attempts to fly while its wings are wet, it has great difficulty getting off the water and takes off by flapping vigorously while 'running' on the water. Anhinga will often search for food in small groups.


Contents

[edit] Distribution and migration

The anhinga genus is found all over the world in warm shallow waters.[2] The American Anhinga has been subdivided into two subspecies - A. a. anhinga and A. a. leucogaster - based on their location. A. a. anhinga can be found mainly east of the Andes in South America and also the islands of Trinidad and Tobago. A. a. leucogaster can be found in the southern United States, Mexico, Cuba, and Grenada.[3]

Only birds that live in the extreme north and south of their range migrate and do so based on temperature and available sunlight. Anhingas will migrate towards the equator during winter but this range is "determined by the amount of sunshine to warm the chilled birds".[2] Although not in their usual range, anhingas have been found as far north as the states of Pennsylvania[4] and Wisconsin[5] in the United States.

Kettles of anhingas often migrate with other birds and have been described as resembling black paper gliders.[6]

close up.
close up.


[edit] Physical description and taxonomy

The A. anhinga species is a large bird and measures approximately 35 in (88.9 cm) in length with a 45 in (1.14 m) wingspan.[7] The A. a. anhinga is larger than A. a. leucogaster and has "broader buffy tail lips".[3] The weight is 2.7 lb (1.22 kg).[8] The bill is long[5] (about twice the length of the head[9]), sharply pointed[7] and yellow as are the webbed[8] feet.

Most of the male Anhinga's body is a glossy black green with the wings, base of wings, and tail being a glossy black blue.[9] The tip of the tail has white feathers.[10] The back of the head and the neck have elongated feathers that have been described as gray[11] or light purple white[9]. The upper back of the body and wings is spotted or streaked with white.[11]

Anhinga drying its feathers.
Anhinga drying its feathers.

[edit] Protected status

The Anhinga is protected in the US under the Migratory Bird Treaty Act of 1918.[1]


[edit] References

  1. ^ BirdLife International (2004). Anhinga anhinga. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006. Database entry includes justification for why this species is of least concern
  2. ^ a b Nellis, David W. (2001). Common Coastal Birds of Florida and the Caribbean. Pineapple Press, Inc., 110. ISBN 978-1-5616-4191-8. 
  3. ^ a b Blake, Emmet Reid (1953). Birds of Mexico: a guide for field identification. University of Chicago Press, 151-152. ISBN 0-2260-5641-4. 
  4. ^ Gerald M. McWilliams, Daniel W. Brauning (1999). Birds of Pennsylvania. Cornell University Press, 43. ISBN 978-0-8014-3643-7. 
  5. ^ a b Robbins,Samuel D. (1991). Wisconsin Birdlife: Population and Distribution Past and Present. University of Wisconsin Press, 127-128. ISBN 978-0-2991-0260-9. 
  6. ^ Ted L. Eubanks, Robert A. Behrstock, Ron J. Weeks (2006). Birdlife of Houston, Galveston, and the Upper Texas Coast. Texas A&M University Press, 70. ISBN 978-1-5854-4510-3. 
  7. ^ a b Sibley, David Allen (2003). The Sibley Field Guide to Birds of Eastern North America. Alfred A. Knopf, New York, 45. ISBN 0-679-45120-X. 
  8. ^ a b David S. Maehr, H. W. Kale, Herbert W. Kale, II (2005). Florida's Birds: A Field Guide and Reference. Pineapple Press Inc, 33,38. ISBN 1-5616-4335-1. 
  9. ^ a b c Audubon, John James (1843). The Birds of America. J.B. Chevalier, 443-457. 
  10. ^ Tom Wood, Sheri L. Williamson, Jeffrey Glassberg. Birds of North America. Sterling Publishing Company, Inc., 50. ISBN 1-4027-2821-2. 
  11. ^ a b Chapman, Frank M.. Handbook of Birds of Eastern North America. Harvard University, 93. 

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