Monday, 18 June 2007

Snake bird

Darters or snake birds (Anhinga melanogaster) are a common sight on lakes and dams in warmer parts of Australia. The distribution is patchier in the south, so it's always exciting to see one of these strange birds.

It sits on the shrubs that hang over the water; and, in a country where every one's ideas are filled with serpents, often terrifies the passengers by shooting out its long, slender neck, which, in their first surprise, they take for the darting of some fatal serpent.
Thomas Pennant et al., Indian Zoology, 1790

Darters swim submerged, with only their necks and heads above water, given them an odd snake-like appearance. They feed mainly on fish. The 8th and 9th cervical vertebrae form a hinge that allows the bird to extend its neck rapidly in a stabbing movement. The birds catch prey by impaling it on the beak, in much the same way as do herons and egrets.

The plumage is not waterproof, so darters must air dry their feathers after immersion. This bird (probably a juvenile) was doing just that on a jetty in Williamstown, Melbourne, this morning.

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