Monday, August 18, 2008

Secretary Bird

 This large, tall and unusual bird of prey is endemic to Africa and inhabits the grasslands (savannah, steppes and the bushvelds), lying to the south of the Sahara Desert.  Some fossil evidences suggest that it may have inhabited Middle East and southern Europe.  It belongs to the order falconiformes which includes the raptors likes kites, vultures, hawks, falcons etc., but is classified as a separate family because of it is distinctiveness.  In fact the secretary bird is the only member of the Sagittariidae family.

The secretary bird has a brightly coloured face that sports a crest of long feathers.  From a distance, the crest resembles a quill of pens that the 19th century clerks stuck to their wigs.  For long, this allusion was thought to be the reason behind the unique name given to the bird, which was discovered by the Europeans in the 19the century.

However, a recent hypothesis states that the name might have evolved from saqr-et-tair, an Arabic term meaning “hunter bird’, whose French equivalent would be secretaire and hence the name Secretary bird.  Also, The scientific name Sagittarius serpentarius can be taken to mean 'The Archer of Snakes' with Sagittarius referring to the archer (greek mythology) and the bird’s quills referring to a quiver of arrows.

It has a eagle like body, a hooked bill but rounded wings and crane like legs, making it stand tall at about 4 feet tall but weighing only about 3-3.5 kg.  The wingspan is about 2m or 6.6 ft. The legs are long and capable of delivering a powerful punch but has its limitations when it comes to grabbing or grasping. The tail has two elongated central feathers that extend beyond the feet, that are useful in deceiving a snake while hunting. All these physical features are actually adaptations to its environment for plain survival and better preying.  Though an accomplished and a graceful flier, it remains largely terrestrial, spending most of its day on the ground and is rarely seen flying.  It roosts on top of the acacia trees but shortly after dawn they drop to ground and spend their day walking across the grasslands (20kms or above in a day), occasionally resting in the shade to escape the brunt of summer.  They are largely silent except for a rare, hoarse, croaking sound they make while displaying. 

Its diet consists of insects, lizards, rats, small mammals and amphibians, though they are known to eat virtually anything that they can swallow.  In addition to these, it preys on snakes also and is in fact, renowned for its ability to catch snakes.  Perhaps the most distinguishing element of the secretary bird as compared to other birds of prey is its hunting technique.  The prey is generally chased on the ground and once it is caught, repeatedly thumped on the head until it becomes unconscious.  Once unconscious the prey is swallowed.  To avoid being bitten by a snake or even if bitten to avoid being poisoned, the secretary bird does something remarkable with the aid of its wings.  The bird will stand slightly back, spread both wings, and erect the crest of feathers at the back of the head and fire away with both talons. Two very long tail feathers will also drop down. The spread wings and feathers act as a false target for venomous creatures, particularly snakes. The two tail feathers are designed to look like a third leg. Because feathers have hollow quills, the bird will not be poisoned if it is bitten in the feathers.

The social structure of the secretary bird is also unique.  The birds are monogamous and have the same partner for its lifetime though members of a pair are usually not together, but instead stay a small distance apart.  The young ones, hatched after an incubation of 45 days, stay with the parents in the nest for two to three months after which they have to fend for themselves.  The pair is extremely faithful to the nest and feed the young ones with partially digested liquid food regurgitated by either of the parents.

The unique or unusual traits and features associated with the secretary bird can be attributed to the unique environment and its evolution to negotiate it.  The Seriemas of the South America is a bird, which is not related to the secretary bird but has similar size and shape owing to the evolution under similar circumstances.

The major threat for the bird is the loss of habitat and from deforestation. The Africa Convention on the Conservation of Nature and Natural Resources declared the Secretary bird as protected species in 1968.

Scientific Classification:

Kingdom: Animalia

Phylum: Chordata

Class: Aves

Order: Falconiformes

Family: Sagittariidae

Genus: Sagittarius

Species: serpentarius

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