Cassowary

Cassowary

Cassowary are flightless birds with no keel on their sternum bones) native to the tropical forests of New Guinea (Papua New Guinea and Indonesia), East Nusa Tenggara, the Maluku Islands and North-Eastern Australia.

Scientific classification  

  • Kingdom: Animalia 
  • Phylum: Chordata 
  • Class: Aves 
  • Order: Casuariiformes 
  • Family: Casuariidae 
  • Genus: Casuarius

There are three species in nature. The most famous of these, the  Cassowary is the third-largest and second-largest living species, smaller than the ostrich and the emu.

Cassowary feeds primarily on fruit, but all species are genuinely omnivorous and will consume a variety of other plant foods, including shoots and grass seeds, as well as fungi, invertebrates and small vertebrates.

Cassowaries are very wary of humans, but if they are provoked, they are capable of causing serious, even fatal, injuries to both dogs and humans. The cassowary has also been called “the most dangerous bird in the world.”

Description

Of the three species of cassowary in the world, only the  cassowary, Casuarius casuarius johnsonii, is present in Australia.

Like the emu and the ostrich, the  cassowary is a ratite, a large flightless bird with peculiar feathers and other features that differentiate it from any other bird.

A striking bird with a glossy black plumage, the adult  cassowary, has a tall brown casque on top of its head, a bright blue and purple body, long drooping red wattles and amber eyes.

The function of a tall helmet or helmet is uncertain, but it may signify dominance and age as it continues to develop throughout life. Recent research suggests that cassowaries can also help to “hear” the low vibrating sound of other cassowaries.

The hull is spongy inside rather than bony, and can also serve as a shock absorber that protects the bird’s head when it pushes through dense rainforest and shrub thickets.

The  cassowary has rough hair-like feathers with no barbels, and it also lacks tail feathers. Its wing stubs hold a small number of long, modified quills that curve around the body.

Every strong, well-muscled leg has three toes, the inside of which has a broad dagger-shaped claw (up to 120 mm long) used to scratch and battle other birds.

New-hatched chicks are striped dark brown and creamy white. After three to six months, the stripes disappeared, and the plumage shifted to brown.

As the young mature, the plumage darkens, the wattles and the helmet grow, and the colour of the skin on the neck and the wattles brighten. The cassowary reaches maturity at around three years of age.

Adult cassowary can grow to an imposing height of 2 m. In general, the appearance of the sexes is somewhat similar, although the females are slightly heavier and can weigh up to 76 kg. Males could weigh up to 55 kg.

Habitat and distribution

At the time of the European settlement of Australia, the  Cassowary was living in tropical rainforests of north-eastern Queensland, from Paluma Range (north of Townsville) to the tip of Cape York.

The cassowary is now present in three broad populations—one population of the Wet Tropics and two populations of Cape York.

Cape York is now split into two distinct populations: the  population of the McIlwraith and Iron vine forests and the northern population of the less comprehensive vine forests north of Shelburne Bay.

Cassowaries in the Wet Tropics are widely distributed from Cooktown to Paluma Range. Approximately 89 per cent of their remaining vital habitat in the Wet Tropics is in safe habitats.

Cassowary habitat in the Wet Tropics has been drastically reduced by land clearing, and the number of cassowary species has also decreased.

Cassowary trees need a large range of fruit trees to provide a year-round supply of fleshy fruits.

While they occur mainly in rainforests, they also use woodlands, melaleucas, mangroves and even beaches, both as intermittent food sources and as a linking habitat between more suitable locations.

Places with a mixture of these habitats are favoured by cassowary people living along the coast.

Diets

Cassowary prefers fruit but consumes small vertebrates, invertebrates, fungi, carrion and plants. More than 238 species of plants have been recorded in the  Cassowary diet.

Cassowary trees have a significant role to play in sustaining the diversity of rainforest trees. The cassowary is one of only a few frugivores (fruit eaters) that can disperse large rainforest fruits and the only species that can transport large seed fruits over long distances.

They swallow the fruit whole, digest the pulp and transfer the seeds unharmed in large piles of dung, spreading them over large areas in the rainforest. Some rainforest seeds also need the cassowary digestive process to help them germinate.

Cassowary scats are large and frequently contain hundreds, if not thousands, of seeds. A ready-made fertilizer, the dung allows many kinds of seed to grow.

White-tailed rats, bush rats, melomies and musky rat-kangaroos also feed on seeds in the  cassowary, helping to further disperse the seeds.

Life history and behaviour

Cassowary animals, typically solitary, live in a home range that varies depending on the season and availability of food.

The scale of the home ranges observed ranged from 0.52 km2 to 2.35 km2. The home range of the  female cassowary typically overlaps with the home range of many males.

The cassowary is territorial, and interaction between adults normally occurs only during mating. From May to November, pairs of cassowary court briefly, mate, and then split. In one season, a female may mate with several males.

Females lay between three and five large, olive-green eggs, usually between June and October. The male has incubated eggs for around 50 days, who guards the eggs and raises the chicks.

Juveniles begin to fend for themselves between the ages of eight and 18 months when they are chased away by the male.

Population threats

A variety of factors influence the survival of the  Cassowary. Significant threats include habitat destruction, fragmentation and alteration, vehicle collisions, dog attacks, human encounters, pigs, disease and natural disasters.

 cassowary habitat, especially in low-lying coastal areas, has been severely reduced by land clearing for agriculture, urban settlement and other development. Urban construction continues to affect populations beyond protected areas.

In Mission Beach, road accidents are the single biggest cause of  Cassowary death. Roads pass through the Cassowary Territories, making it possible for birds to fly through them in search of food. Birds may also be drawn to roads by people who feed them or throw garbage from vehicles.

Unrestrained and wild dogs are another major cause of  cassowary mortality, especially in areas near residential development.

Chicks and sub-adults are small enough to kill dogs, and dog packs often kill adult birds, chase them until they are tired, and then attack them.

Dogs also have an indirect impact on the cassowary by their very presence, affecting the feeding, gestures and general behaviour of birds.

Domestic dogs may also target and kill cassowaries as they walk through suburban areas in search of food or water.

Pigs cause rain forest disturbance and fight with the cassowary for the fruit they have dropped. They can also eat  cassowary eggs and wreck nests.

Pig control practices can also be dangerous to the cassowary, particularly when dogs are let loose to chase pigs and end up finding and attacking cassowary instead.

Cassowary hand-feeding is a concern for both birds and humans. Wild cassowary food-conditioned human food sources can be aggressive in defending themselves or their chicks, or in finding other human food.

If birds become less wary of humans, they may become more vulnerable to dog attacks and road mortality as they search for food.

In recent years, cyclones have destroyed large areas of  cassowary habitat, leading to temporary food shortages. This can place more stress on local populations already at risk from habitat fragmentation, dogs and vehicle strikes.

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