From the field... King vulture the only true rainforest vulture

Abstract

The hours passed slowly in my canvas blind erected in the Mountain Pine Ridge Forest Reserve in Belize, Central America. I had earlier placed several (dead) goats in a nearby ravine in hopes of observing the feeding behavior of the king vulture (Sarcoramphus papa). Suddenly a great rush of air created waves across the top and sides of my blind. Soon the giant majestic black and white bird with its wing spread of seven feet and weight of over seven and a half pounds was in full view. Twisting and turning as it descended, it displayed with great precision how these large birds of prey have complete control over the winds and thermal currents. Having just landed, the vulture walked with powerful legs over to the carcasses and began feeding.

Like the Indian king vulture (Sarcogyps caivus) the American king undoubtedly received its title because of its behavioral attribute of displacing (being dominant over) the other smaller vultures. The American king also plays an important role in the opening of larger carcasses therefore facilitating the feeding on them by the other vultures and carrion feeding mammals. Being the only vulture that can penetrate the thick hides of domestic cattle and wild deer and tapir, I have observed countless times, a number of smaller black and turkey vultures perched with crested caracaras above roadkilled animals. Unable to open the hides they awaited the arrival of the king.

In areas of Mexico where the king vulture is no longer found, large animals are left to decompose by bacterial organisms if a wound was not created in the course of the killing of the animal.

Not documented feeding on snakes, small rodents or fish, the king soars, usually in pairs or alone, above the tropical forest and adjoining areas. They do feed on domestic livestock but are wary of man's presence. Even at large kills seldom do you encounter a number of kings feeding. During three months of research on this species in Central America I recorded only three cases of more than five individuals feeding together. Not being terribly rare they appear to function better in smaller groups, which is rather unusual when one reviews the social nature of the remairung six species of New World (Cathartidae) vultures.

Ranging from Southern Mexico to Northern Argentina, the species is generally associated with the dense tropical forest. Frequently observed feeding on domestic livestock it has adapted well to man's alterations of the environment. Although the breeding requirements in the wild are not complete- 1 y known, all the nests thus far discovered were in dense forests near rivers. It is my personal feeling that the specie's survival is closely tied to the forest. Although a number of kings have been discovered in South America in thorn forests they have not been recorded to have successfully reared young under those circumstances so may be simply existing and not viable.

It is interesting to note that the king vulture is abundant in areas where the scarlet macaw (Ara Macao) can also be found as along the Usumacinta River on both Mexico and Guatemala borders, and in the Guacamayo Forest Reserve in Belize. In areas where the scarlet macaw has not been recorded for some time the king too is only infrequently sighted as in the palenque ruins area in Chiapas, Mexico.

As the king vulture is not captured for the pet trade this is an excellent example of how habitat destruction affects all avian forms. The king is able to survive with man (although at a distance and only if man continues to mismanage his livestock) but the scarlet, except for occasional cornfield robbing, is not terribly adaptable.

One of the most interesting aspects of this species is its coloration. One of the topics under investigation by Niel Smith at the Smithsonian Tropical Research Institute in Panama is why large soaring birds are the colors that they are. Certainly this is an interesting question. The king vulture upon maturity (which requires from 5-6 years) is mainly creamy white with half the wings, rump and tail being black. Its neck is striking in coloration, being yellow, red, blue and purple in varying shades and getting more brilliant during courtship. To top off this ''bewilderingly beautiful'' coloration the iris is white. Both sexes are the same...

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