Darter

Darter  Anhinga melanogaster

Etymology:

  • Anhinga : Tupí name Anhinga –  little head, for an evil spirit of the forests, the devil bird
  • Melanogaster : Mela- black ; Gaster – Stomach { Black Bellied}

Vernacular Names: Sind: Silli, Hindi: Panwa, Pandubbi, Sans: Madrugu, Pun: Bhujanga, Bambi, Ben: Goyar, Ass: Maniori, Bejiagir, S.Gonds: Chakuri, Guj: Sarpagreeva, Surpgriv, Mar: Sarpapakkshi, Tirandaz, Ta: Pambuttara, Te: Pamubatu, Kan: Haavvakki, Sinh: Diya kawa, Belli kawa

Distribution in India: Resident in North, West and Southern parts of the country. Winter visitor in Central India

Description: Size of 85-97 cm. Males have black and dark-brown plumage, a short erectile crest on the nape and a larger bill than the female. The females have much paler plumage, especially on the neck and underparts, and are a bit larger overall. Both have grey stippling on long scapulars and upper wing coverts. The sharply pointed bill has serrated edges and no external nostrils. The darters have completely webbed feet, and their legs are short and set far back on the body. During breeding, their small gular sac changes from pink or yellow to black, and the bare facial skin, otherwise yellow or yellow-green, turns turquoise.

Habitat: It is found in still, shallow inland waters, such as freshwater or alkaline lakes, slow flowing rivers, swamps and reservoirs; less often estuaries or tidal inlets and coastal zones with mangroves and lagoons. Requires scattered emergent trees, forested margins or islets with dense vegetation.

Food Habits: Darters feed mainly on mid-sized fish far more rarely, they eat other aquatic vertebrates and large invertebrates of comparable size. These birds are foot-propelled divers which quietly stalk and ambush their prey; then they use their sharply pointed bill to impale the food animal. They do not dive deep but make use of their low buoyancy made possible by wettable plumage, small air sacs and denser bones. On the underside of the cervical vertebrae 5–7 is a keel, which allows for muscles to attach to form a hinge-like mechanism that can project the neck, head and bill forward like a throwing spear. After they have stabbed the prey, they return to the surface where they toss their food into the air and catch it again, so that they can swallow it head-first. Like cormorants, they have a vestigial preen gland and their plumage gets wet during diving. To dry their feathers after diving, darters move to a safe location and spread their wings. Darters go through a synchronous moult of all their primaries and secondaries making them temporarily flightless, although it is possible that some individuals go through incomplete moult.

Breeding Habits: They breed is seasonal peaking in March- April. They usually breed in colonies, occasionally mixed with cormorants or herons. The darters pair bond monogamously at least for a breeding season. There are many different types of displays used for mating. Males display to attract females by raising their wings to wave them in an alternating fashion, bowing and snapping the bill, or giving twigs to potential mates. To strengthen the pair bond, partners rub their bills or wave, point upwards or bow their necks in unison. When one partner comes to relieve the other at the nest, males and females use the same display the male employs during courtship; during changeovers, the birds may also “yawn” at each other. The nests are made of twigs and lined with leaves; they are built in trees or reeds, usually near water. Typically, the male gathers nesting material and brings it to the female, which does most of the actual construction work. Nest construction takes only about three days and the pairs copulate at the nest site. The clutch size is two to six eggs . The eggs are laid within 24–48 hours and incubated for 25 to 30 days, starting after the first has been laid; they hatch asynchronously. To provide warmth to the eggs, the parents will cover them with their large webbed feet, because like their relatives they lack a brood patch. Bi-parental care is given and the young are Altricial. They are fed by regurgitation of partly digested food when young, switching to entire food items as they grow older. After fledging, the young are fed for about two more weeks while they learn to hunt for themselves. These birds reach sexual maturity by about two years
Darter eggs are edible and considered delicious by some; they are locally collected by humans as food. The adults are also eaten occasionally, as they are rather meaty birds (comparable to a domestic duck); like other fish-eating birds such as cormorants or seaducks they do not taste particularly good though. Darter eggs and nestlings are also collected in a few places to raise the young. Sometimes this is done for food, but some nomads in Assam and Bengal train tame darters to be employed as in cormorant fishing. With an increasing number of nomads settling down in recent decades, this cultural heritage is in danger of being lost. On the other hand, as evidenced by the etymology of “anhinga” detailed above, the Tupi seem to have considered the anhinga a kind of bird of ill omen