Anhinga (Anhinga anhinga)

       

Class:	Aves
Order:	Pelicaniformes
Family:	Anhingidae
Size:	Length: 28 to 35 inches (71 to 89 cm)  Wingspan: 48 inches (122 cm)
Weight:	3 pounds (1.3 kg)
Diet:	Mostly fish, but also aquatic invertebrates, reptiles and amphibians
Distribution:	North America, Central America and South America
Young:	2 to 6 eggs
Animal Predators:	Alligators
IUCN Status:	No special status
Terms:	Young: Chick
Lifespan:	10 to 12 years

 

Facts/Trivia:

·      Anhinga is a native South American name that means “water turkey.”

·     Other names for this bird are “American darter,” “black darter” and “snake bird.”

·     Although anhingas are very similar to cormorants, cormorants have hooked bills and shorter tails and necks. 

·     A mated pair show affection by intertwining their necks. 

 

Description

Anhingas have a very long, thin neck and a long, sharp bill. The males have shiny blackish-green feathers covering their head, neck and body, while females have a light brown head and neck, but a black body. Both genders have a long, fan-shaped tail and white streaks on their wings. Unlike most other water birds, they do not have oil glands that waterproof their feathers. This allows them to dive under and through water with greater ease, but gives them less buoyancy. As well, having wet feathers inhibits their flying ability, so when they emerge from the water they usually perch in a treetop and hold their wings out in the sun to dry. This also warms them up, as their body temperature drops while in water. 

 

Habitat

These water birds range from the southeastern United States to Argentina. They are always found near a water source such as swamps, lakes, slow-moving streams, bays and lagoons. They roost and nest in a tree or bush. 

 

Feeding Habits

Anhingas were dubbed “snake birds” because they swim with their head and long neck above water, giving the appearance of a snake. When they find a slow-moving fish, they spear it with their long, pointy bill. They then bring the fish to shore and pry the fish off by rubbing it against a solid object such as a rock or tree trunk. They also eat aquatic invertebrates, reptiles and amphibians. 

 

Reproduction

Anhingas form lifelong monogamous relationships. Once a pair has been formed, the male chooses a nesting site and brings sticks and leaves to the female, who builds the nest. The nest is lined with soft moss and sits in the branches of a tree, several feet above the water. Anhingas are sociable birds and build their nests in colonies that include other  bird species such as herons, storks, cormorants and egrets. When the nest is ready, the female lays her eggs in one to three day intervals. The parents take turns incubating the eggs. Between 25 and 30 days later, the chicks hatch. They are born helpless, without feathers and with their eyes shut. For the next 12 days, their parents keep them warm and feed them regurgitated fish. By then, their eyes have opened and they begin to explore the nest, but they still need to be fed and cared for by their parents. By the time they are three weeks old, they can drop down from the nest into the water and swim, then climb out of the water and back into the nest. When they are six weeks old, their flight feathers have grown in and they begin their first attempts at flight. Several weeks later, the young anhingas leave the nest to head out on their own. 

 

Behaviour

Anhingas take off for flight by running on the water’s surface or by diving from a height, such as a tree branch. To enter the water, they walk directly into it from the bank or by gliding down onto the surface. They can be found either alone or in groups of other water birds. When in flight, they often soar on air currents for extended periods, flapping their wings only rarely. 

Conservation

Anhinga numbers at one time were diminishing due to a pesticide called DDT. The chemical was ingested by the anhinga’s prey, entering the bloodstream of these birds in a high concentration and harming not only their ability to reproduce, but creating thinner shells in their eggs, resulting in their loss. When DDT was banned in the United States in 1972, anhinga populations recovered and they are now abundant, although their habitat is still diminishing. They are listed as Endangered in Kentucky and Of Special Concern in Tennessee and North Carolina.

 

Sources

http://www.mbr-pwrc.usgs.gov/id/framlst/i1180id.html

http://www.geocities.com/Heartland/5960/anhing.html

http://museum.nhm.uga.edu/gawildlife/birds/pelecaniformes/aanhinga.html

http://animaldiversity.ummz.umich.edu/accounts/anhinga/a._anhinga$narrative.html

http://www.audubon.org/local/sanctuary/corkscrew/Wildlife/Birds/Waterbirds.html

http://www.texasbirding.net/birds/anhinga.htm

http://aviary.owls.com/anhinga/anhinga.html