Of the 3 species of cassowaries in the world, only the southern cassowary, (Casuarius casuarius johnsonii), is found in Australia. Like the emu and ostrich, the southern cassowary is a ratite, a large flightless bird with unusual feathers and other features that distinguish it from all other birds.
A striking bird with glossy black plumage, the adult southern cassowary has a tall, brown casque (helmet) on top of its head, a vivid blue and purple neck, long drooping red wattles and amber eyes. The purpose of the casque is unknown but it may indicate dominance and age, as it continues to grow throughout life. Recent research indicates it may also help cassowaries in ‘hearing’ the low vibrating sound made by other cassowaries. The casque is spongy inside, rather than bony, and may also act as a shock absorber that protects the bird’s head when it pushes through dense thickets of rainforest and scrub.
The cassowary has coarse hair-like feathers, and lacks tail feathers. Its wing stubs carry a small number of long, modified quills which curve around the body. Each heavy, well-muscled leg has 3 toes, with the inside toe bearing a large dagger-shaped claw (up to 120mm long) used for scratching and fighting other birds.
Newly-hatched chicks are striped dark brown and creamy white. After 3 to 6 months the stripes fade and the plumage changes to brown. As the young mature, the plumage darkens, the wattles and casque develop and the skin colour on the neck and wattles brighten. Cassowaries reach maturity at about 3 years.
Adult cassowaries can grow to an imposing 2m tall. In general, the sexes are fairly similar in appearance, though females are slightly larger and can weigh up to 76kg. Males can weigh up to 55kg.
Habitat and distribution
At the time of European settlement of Australia, the cassowary lived in tropical rainforests of North East Queensland, from Paluma Range (north of Townsville) to the tip of Cape York. Cassowaries are now found in 3 broad populations—1 population in the Wet Tropics and 2 populations in Cape York.
In Cape York there is a southern population in the vine forests of the McIlwraith and Iron ranges and a northern population in the less extensive vine forests north of Shelburne Bay.
In the Wet Tropics, cassowaries are distributed widely from Cooktown to Paluma Range. Approximately 89% of their remaining essential habitat in the Wet Tropics is protected from development. Cassowary habitat in lowland sections of the Wet Tropics has been greatly reduced by land clearing, so cassowary numbers have decreased in those areas.
Cassowaries require a high diversity of fruiting trees to provide a year-round supply of fleshy fruits. Although living primarily in rainforests, they also use woodlands, melaleuca swamps, mangroves and even beaches for food sources and as connecting habitat between more suitable sites. Cassowaries that live near the coast prefer places with a mix of these environments.
Cassowaries prefer fallen fruit, but will eat small vertebrates, invertebrates, fungi, carrion (dead flesh) and plants. Over 238 species of plants have been recorded in the cassowary diet.
Cassowaries are important for maintaining the diversity of rainforest trees. They are one of only a few frugivores (fruit eaters) that can disperse large rainforest fruits, and the only one that can carry them over long distances.
They swallow the fruit whole, digesting the pulp and passing the seeds unharmed in large piles of dung, distributing them over large areas throughout the rainforest. Some rainforest seeds require the cassowary digestive process to help them germinate. Cassowary scats are large and often contain hundreds, if not thousands of seeds. A ready-made fertiliser, the dung helps many kinds of seed to grow. White-tailed rats, bush rats and musky rat-kangaroos sometimes feed on seeds in cassowary droppings, helping to further distribute the seeds.
Life and behaviour
Usually solitary animals, cassowaries live in different areas depending on season and availability of food. Their home spans between 0.52km2 and 2.35km2. The home of a female cassowary usually overlaps with the home of several males. Cassowaries are territorial, and contact between adults generally only occurs during mating. From May to November, pairs of cassowaries court briefly, mate and then separate. A female can mate with several males in one season.
Females lay between 3 to 5 large, olive-green eggs, generally between June and October. Eggs are incubated by the male for about 50 days, who alone guards the eggs and raises the chicks. Juveniles begin to fend for themselves from about 8 to 18 months, when they are chased away by the male.
Threats to cassowaries
Major threats to cassowary survival include loss, break up and changes to habitat, road accidents, dog attacks, human interactions, pigs, disease and natural catastrophic events.
Cassowary habitat, particularly on the coastal lowlands, has been seriously reduced by land clearing for farming, urban settlement and other development. Urban development continues to threaten the populations outside of protected areas.
In the Mission Beach area, road accidents are the greatest cause of cassowary death. Roads cut through cassowary territories, making it necessary for the birds to travel across them in search for food. Birds can also be attracted to roads by people feeding them or throwing litter from vehicles.
Unrestrained and wild dogs are another major cause of cassowary deaths, particularly near residential areas. Chicks and young adults are small enough to be killed by dogs. However, packs of dogs also kill adult birds, pursuing them until they are exhausted, then attacking them. Dogs also indirectly affect cassowaries through their very presence, influencing the feeding, movements and general behaviour of the birds. Domestic dogs can also attack and kill cassowaries when they wander into suburban areas seeking food or water.
Pigs cause disturbance to the rainforest and compete with cassowaries for fallen fruit. They may also eat cassowary eggs and destroy nests. Pig control activities may also be hazardous to cassowaries, particularly when dogs are let loose to hunt pigs, and end up finding and attacking cassowaries instead.
Hand-feeding of cassowaries is a risk to birds and people. Wild cassowaries conditioned to human food can be aggressive when protecting themselves or their chicks, or seeking other human food. As birds become more comfortable around humans, they may become more vulnerable to dog attack and road mortality as they move around looking for food.
In recent years, cyclones have damaged large areas of cassowary habitat, causing temporary food shortages. This may have placed further stresses on local cassowary populations.
Protecting the species
The Recovery plan for the southern cassowary sets out actions to secure the long-term protection of the cassowary.
Local residents in cassowary areas are establishing nurseries of cassowary food plants so that revegetation can be used to restore cassowary habitat on cleared land, and create corridors between existing patches of habitat.
Local government planning can also be used to protect cassowary habitat.
The Queensland Government has mapped the habitat of the cassowary. This information can then be considered when assessing future developments.
A method for estimating cassowary numbers from genetic material in cassowary scats is being developed by the CSIRO. Recent work has shown that cells from the stomach lining of cassowaries are passed out in their scats. By collecting these scats and analysing the cells found in them, it may be possible to identify the sex and genetic code of each bird. These results may help to estimate the size of populations, as well as how far birds move and their breeding patterns.
How can you help?
Everyone can help protect our cassowaries. If you live in or visit cassowary territory, follow these tips:
- Leave vegetation on your property, especially in gully heads and along creek banks, as these are feeding grounds and corridors for cassowaries.
- Be careful when driving. Slow down to avoid hitting any animals but don't stop to watch them.
- Restrain your dog, especially when cassowaries are around.
- Never feed cassowaries, especially on the side of the road where they may get hit by passing cars.
- Let cassowaries find their own food. If you feed them, they may come to depend on you—their health will suffer and they may starve when you go away or move elsewhere. It may also make them aggressive towards other people.
- Plant cassowary food plants. The Cassowary Recovery Team provide advice about the best trees to plant.
- If you would like to make a commitment to protecting cassowary habitat on your property, contact us and ask about nature refuges.
Cassowaries are uncommon and may be hard to find. For such big, colourful birds, they blend remarkably well into rainforest shadows.
Look for signs such as characteristic large dung piles, full of seeds, scattered on the rainforest floor (often on walking tracks), and the large 3-toed footprint (up to 180mm). Listen for a deep rumbling sound which the bird makes to advertise its presence and respond to danger.
You're most likely to see cassowaries around Mission Beach. You may also see them at the Wallaman Falls Section of Girringun National Park, the Cape Tribulation Section of Daintree National Park, the Palmerston Section of Wooroonooran National Park and around Kuranda.
Cassowaries can be aggressive and unpredictable.
These simple safety tips can help protect you.
- Never approach cassowaries. They can injure you or your pet with their large, clawed feet.
- Never approach chicks—male cassowaries will defend them.
- Never feed cassowaries—it is illegal, dangerous and has caused cassowary deaths.
- Always discard food scraps in closed bins and ensure compost bins have secure lids.
- Always slow down when driving in cassowary territory.
- Never stop your vehicle to look at cassowaries on the road.
- Keep dogs behind fences or on a leash.
If you come face-to-face with an aggressive bird, back away slowly and put something like a tree or a backpack between yourself and the bird, then let it go on its way.