Ibises
Ibises
Ibises are grouped together with large wading birds such as storks, herons, flamingos, and spoonbills, in the order Ciconiiformes. Ibises, like most birds in this order, have long legs and a long bill for feeding on fish and aquatic animals in shallow water. They also have broad wings, a short tail, and four long toes on each foot. The 26 species of ibis share the family Threskiornithidae with the spoonbills. Ibises have a large body, long legs, and a characteristic thin, downward-curving bill. The plumage of male and female ibises is alike, but the females are generally smaller. The heavy body of ibises means that they must flap their wings rapidly when in flight. They fly with their neck extended, often in a characteristic V-formation.
In North America, ibises are represented by the white ibis (Eudocimus albus ), glossy ibis (Plegadis flacinellus ), and white-faced ibis (P. chihi ). The wood ibis (Mycteria americana ) is not actually an ibis, but a stork (Ciconidae ). The scarlet ibis (Eudocimus rubra ) is the most spectacular ibis of South America and the Caribbean. The sacred ibis (Threskiornis aethiopicus ), the glossy ibis, and the hadada ibis (Bostrychia hage-dash ) are the principal species found in Africa.
Habitat and behavior
Ibises are found on shores and marshes worldwide, mainly in tropical habitats, but some are found in south-temperate regions. Ibises feed in flood plains, marshes, and swamps, and along streams, ponds, and lakes. Their diet is varied, consisting of aquatic invertebrates, insects, snails, fish, reptiles, amphibians, and even small mammals. Generally, ibises feed in large groups of up to 100 birds, and the flock may include other species of waders. Ibises usually feed by wading through shallow water and grabbing available prey with their beak.
Some species of ibis are solitary in their nesting habits within a prescribed territory, but most nest in large colonies of up to 10,000 pairs. Within the colony there may be several different species of ibis. These birds tend to be monogamous (faithful to a single mate) during a breeding season, but observers have also noted promiscuous mating within the large colonies.
Both male and female ibises build the nest, protect it from intruders, incubate the eggs (from two to six at a time), feed the fledglings, and care for them for about a month after they are hatched. Before mating, there is a courtship period, involving displays and the enhancement of the color of the face, legs, bill, and exposed parts of the bird’s skin.
The series of courtship behaviors that ibises display (preening, shaking, and bill popping) are ritualized, beginning when the birds gather near secluded nesting areas. The male birds display, the females are attracted to them, and mating follows. Males may behave aggressively in defending their nesting site from other males, but they can also act aggressively towards females not selected as the mate.
Display preening involves pretending to preen the front or back feathers. Display shaking involves shaking loose wings up and down, and bill popping involves snapping the bill up and down with a popping sound. Ibises also have a sleeping display, in which they pretend to be asleep. The head rub during courtship is a sign for the female to enter the nesting area, where she performs a bowing display, keeping her head and body low as she comes near the male. The male may pretend to be aggressive before he finally allows the female to enter his nesting area. Head shaking is one of the displays ibises perform after mating as a greeting and acceptance. The intimacy of their relationship can be seen in mutual preening of one another, shaking, and the rubbing of their heads against each other.
Historical references
There are references to ibises in the Bible. Moses was told by God not to eat them, and they were also
referred to as birds of doom in other parts of the Bible. The ancient Egyptians considered the sacred ibis to be a sacred bird. Drawings, statues, and mummified ibises have been found in abundance in cemeteries dedicated to them. At a location near Memphis, Egypt, 1.5 million mummified birds were found. However, the sacred ibis has been absent from Egypt for well over 100 years, because of excessive hunting and habitat loss.
The Egyptian god of wisdom and knowledge, Thoth, is depicted in ancient Egyptian artifacts as a man with the head of an ibis. During the fourth and fifth centuries BC, ibises were engraved on Greek coins. During the Middle Ages, Austrian nobles ate ibis as a delicacy. They were first described scientifically by a European naturalist, Konrad Gesner, in the sixteenth century. By the middle of the seventeenth century, they disappeared from central Europe, and the bird that Gesner described and painted was not noted again until it was seen in 1832 near the Red Sea. In the nineteenth century, a society of British ornithologists named their journal for the ibis.
A number of species of ibises are endangered. Among these is the formerly widespread waldrapp or northern bald ibis (Geronticus eremita ), which is reduced to present-day populations in Turkey. There are 800 waldrapps in zoos all over the world and efforts are being made to reintroduce them into their former habitat. Other endangered species are the southern bald ibis (G. calvus ) of southern Africa, the dwarf olive ibis (Bostrychia bocagei ) of the island of Sao Tome in West Africa, the crested ibis (Nipponia nippon ) of Asia, the giant ibis of Vietnam (Thaumatibis gigantea ), the Madagascar sacred ibis (Threskiornis bernieri ), and the white-shouldered ibis (Pseudibis davidsoni ) of Vietnam and Borneo. As with many other animals, the destruction of natural habitat, especially wetland drainage, is the primary threat to these wading birds. However, they are also hunted as food.
Resources
BOOKS
Bildstein, Keith L. White Ibis: Wetland Wanderer. Washington, DC: Smithsonian Institution Press, 1993.
Boylan, P. Thoth: The Hermes of Egypt. 1922. Reprint. Chicago: Ares Publishers, 1987.
del Hoyo, J., A. Elliott, and J. Sargatal. Handbook of the Birds of the World. Vol. 1, Ostriches to Ducks. Barcelona: Lynx Edicions, 1992.
Hancock, James A., James A. Kushlan, and M. Philip Kahl. Storks, Ibises and Spoonbills of the World. London: Academic Press, 1992.
Vita Richman
Ibises
Ibises
Ibises are grouped together with large wading birds such as storks , herons , flamingos , and spoonbills, in the order Ciconiiformes. Ibises, like most birds in this order, have long legs and a long bill for feeding on fish and aquatic animals in shallow water . They also have broad wings, a short tail, and four long toes on each foot. The 26 species of ibis share the family Threskiornithidae with the spoonbills. Ibises have a large body, long legs, and a characteristic thin, downward-curving bill. The plumage of male and female ibises is alike, but the females are generally smaller. The heavy body of ibises means that they must flap their wings rapidly when in flight. They fly with their neck extended, often in a characteristic V-formation.
In North America , ibises are represented by the white ibis (Eudocimus albus), glossy ibis (Plegadis flacinellus), and white-faced ibis (P. chici). The wood ibis (Mycteria americana) is not actually an ibis, but a stork (Ciconidae). The scarlet ibis (Guara rubra) is the most spectacular ibis of South America and the Caribbean. The sacred ibis, the glossy ibis, and the hadada ibis are the principal species found in Africa .
Habitat and behavior
Ibises are found on shores and marshes worldwide, mainly in tropical habitats, but some are found in south-temperate regions. Ibises feed in flood plains, marshes, and swamps, and along streams, ponds, and lakes. Their diet is varied, consisting of aquatic invertebrates , insects , snails , fish, reptiles , amphibians , and even small mammals . Generally, ibises feed in large groups of up to 100 birds, and the flock may include other species of waders. Ibises usually feed by wading through shallow water and grabbing available prey with their beak.
Some species of ibis are solitary in their nesting habits within a prescribed territory, but most nest in large colonies of up to 10,000 pairs. Within the colony there may be several different species of ibis. These birds tend to be monogamous (faithful to a single mate) during a breeding season, but observers have also noted promiscuous mating within the large colonies.
Both male and female ibises build the nest, protect it from intruders, incubate the eggs (from two to six at a time), feed the fledglings, and care for them for about a month after they are hatched. Before mating, there is a courtship period, involving displays and the enhancement of the color of the face, legs, bill, and exposed parts of the bird's skin.
The series of courtship behaviors that ibises display (preening, shaking, and bill popping) are ritualized, beginning when the birds gather near secluded nesting areas. The male birds display, the females are attracted to them, and mating follows. Males may behave aggressively in defending their nesting site from other males, but they can also act aggressively towards females not selected as the mate.
Display preening involves pretending to preen the front or back feathers. Display shaking involves shaking loose wings up and down, and bill popping involves snapping the bill up and down with a popping sound. Ibises also have a sleeping display, in which they pretend to be asleep. The head rub during courtship is a sign for the female to enter the nesting area, where she performs a bowing display, keeping her head and body low as she comes near the male. The male may pretend to be aggressive before he finally allows the female to enter his nesting area. Head shaking is one of the displays ibises perform after mating as a greeting and acceptance. The intimacy of their relationship can be seen in mutual preening of one another, shaking, and the rubbing of their heads against each other.
Historical references
There are references to ibises in the Bible. Moses was told by God not to eat them, and they were also referred to
as birds of doom in other parts of the Bible. The ancient Egyptians considered the sacred ibis (Threskiornis aethiopicus) to be a sacred bird. Drawings, statues, and mummified ibises have been found in abundance in cemeteries dedicated to them. At a location near Memphis, Egypt, 1.5 million mummified birds were found. However, the sacred ibis has been absent from Egypt for well over 100 years, because of excessive hunting and habitat loss.
The Egyptian god of wisdom and knowledge, Thoth, is depicted in ancient Egyptian artifacts as a man with the head of an ibis. During the fourth and fifth centuries b.c., ibises were engraved on Greek coins. During the Middle Ages, Austrian nobles ate ibis as a delicacy. They were first described scientifically by a European naturalist, Konrad Gesner, in the sixteenth century. By the middle of the seventeenth century, they disappeared from central Europe , and the bird that Gesner described and painted was not noted again until it was seen in 1832 near the Red Sea. In the nineteenth century, a society of British ornithologists named their journal for the ibis.
A number of species of ibises are endangered. Among these is the formerly widespread Waldrapp ibis, which is reduced to present-day populations in Turkey.
There are 800 Waldrapp ibises in zoos all over the world and efforts are being made to reintroduce them into their former habitat. Other endangered species are the bald ibis of southern Africa, the dwarf olive ibis of the island of Sao Tome in West Africa, the oriental crested ibis of Asia , the giant ibis of Vietnam, and the white-shouldered ibis of Vietnam and Borneo. As with many other animals, the destruction of natural habitat, especially wetland drainage, is the primary threat to these wading birds. However, they are also hunted as food.
Resources
books
Bildstein, Keith L. White Ibis: Wetland Wanderer. Washington, DC: Smithsonian Institution Press, 1993.
Boylan, P. Thoth: The Hermes of Egypt. 1922. Reprint. Chicago: Ares Publishers, 1987.
Campbell, N., J. Reece, and L. Mitchell. Biology. 5th ed. Menlo Park: Benjamin Cummings, Inc. 2000.
Hancock, James A., James A. Kushlan, and M. Philip Kahl. Storks, Ibises and Spoonbills of the World. London: Academic Press, 1992.
Vita Richman