DCSIMG


Search

Double-Wattled Cassowary

Order: Struthioniformes
Family: Casuariidae
Species: Casuarius casuarius

Description

The double-wattled cassowary is one of the largest birds in the world. Weighing as much as 128 pounds, only the ostrich is heavier. Flightless birds, cassowaries are covered in coarse black feathers, with the exception of the skin on the head and throat which is brightly colored red and blue. These coarse feathers are an adaptation to the thick vegetation of the rain forest where cassowaries live. The flight feathers are reduced to five or six quills on both sides of their body that protect the bird when it is traveling through the undergrowth. One of the cassowary's most distinguishing features is the large protuberance on the top of its head called the casque.

It is believed that the casque assists the cassowary in pushing through the dense tropical forest vegetation, and may also provide some sort of protection. In captivity, cassowaries have been observed using their casques like a shovel to search for food on the ground. It is believed that the size of the casque may indicate dominance and age, since the casque continues to grow throughout the life of the bird. Another distinguishing feature of the cassowaries is their wattles. Wattles are present in two of the three species of cassowary. These brilliantly colored folds of skin hang from the bird's neck, and may act as social signals in the dark forest. Cassowaries have powerful legs and feet that enable them to run up to 30 miles per hour and jump as high as five feet. Their feet are equipped with sharp claws and the inner toe is formed into a long dagger-like claw that can be a formidable weapon.

Distribution and Habitat

Double-wattled cassowaries are found in New Guinea and northern Australia. They are most often found in the rain forest, occasionally straying to swampy forested areas. They are excellent swimmers and are often found along river banks.

Diet

Cassowaries are frugivorous birds. The majority of their food is found on the floor of the rainforest where it has fallen from trees above. They also eat fruit from branches they can reach. They occasionally consume small vertebrates, fungi, and insects. One study discovered that the cassowary is an important disperser of many species of rainforest plants. It was found that many of the seeds and fruits the cassowary ate passed nearly intact through the digestive tract of the bird. Although germination occurred at a variable rate in the cassowary dung, it did occur in 70 out of 78 species of seeds that the cassowary consumed.

Reproduction

Generally solitary birds, cassowaries come together only during the breeding season. Reproduction occurs during the dry season of June to October, when the food supply is greatest and when chicks have the best chance of survival. Courtship is initiated by the male when a female enters his territory. The smaller sized male must approach the larger female carefully, because if she is not receptive, she is capable of seriously injuring him. The male begins courtship by circling around the female and making a low rumbling sound. Occasionally, the female circles the male. Once copulation has occurred, the pair may remain together for several weeks. During this time the female lays three to five light green eggs in a nest that the male has constructed. The nest is a shallow scrape in the ground in which the male has placed leaves and grass.

Once the female has laid her eggs, she leaves the male in search of another male with whom she may repeat the courtship process. She plays no part in incubating or in rearing of the chicks. Incubation is carried out entirely by the male for about 50 days. The brown, striped chicks are able to follow the male around in search of food several hours after hatching. The male stays with the chicks for approximately nine months protecting them from predators and teaching them to find food on their own. During this time, the chicks lose their striped markings and molt into a light brown plumage. The skin on the neck and head begins to turn color, and the casque begins to develop. Over the next two years, they gradually molt into the black plumage, and develop wattles. Cassowaries are capable of breeding when they are three years old. Life spans in captivity can reach 20 to 40 years.

Relationship with People

Cassowaries are very important to the native people of New Guinea both economically and ritually. Cassowaries have been traded for pigs and even for a wife. Some tribes hunt them for their meat which is considered a delicacy. They use the feathers to decorate headdresses, and the feather quills for earrings. The sharp claws are often placed at the tips of arrows, while the strong leg bones are used as daggers. Cassowaries have been traded throughout Asia for at least 500 years, and it is believed that this is how the double-wattled cassowary reached Australia. For many native people, cassowaries are full of legends and mystical powers. Some tribes believe that cassowaries are reincarnations of female ancestors, while others believe that the cassowary is the primal mother. These tribes do not hunt or deal in trade with cassowaries.

Conservation

Although none of the three species of cassowary are globally threatened, all are suffering from loss of habitat. Their strict ecological needs mean that they are especially vulnerable to shrinking habitats. As rainforests are cleared, cassowaries are forced from one forest to another, often crossing roads where they are in danger of being hit by passing cars. Introduced feral pigs and dogs prey often upon chicks. In New Guinea, an increase in the price of cassowary feathers by the native people, has led to an increase in hunting of the cassowary.


References

Coates, B. 1985. The Birds of Papua New Guinea (Vol.1). Dove Publications, Queensland

Del Hoyo, J., Elliot, A. and J. Sargatal. eds. 1992. Handbook of the Birds of the World. Vol. 1. Ostrich to Ducks. Lynx Edicions, Barcelona.