These large flightless birds play an important role in the dispersal of rainforest plant seeds and Cassowary populations face a variety of threats as habitat disappears, human contact with cassowaries is increasing.
The southern cassowary (Casuarius Casuarius) is one of the most striking and certainly by far the largest bird to be found in the Australian rainforests.
To describe the cassowary it is a large flightless land bird, impressive in size, with course glossy black plumage, tall helmet and brilliant red and blue neck and wattles as distinctive features.
The feathers of the cassowary are extraordinary and have 2 shafts, giving the feathers a hair like appearance. It is thought that the adaptation of these feathers to this hair like appearance may be that they are more effective for insulation and for shedding rain than feathers, which are adapted for flight.
The tall helmet or ‘casque’ that forms on maturing birds and continues to grow as they age consists of light cellular foam like material covered with a delicate skin. Despite its horny appearance, the casque is very delicate and can be easily damaged. The casque may serve as an indicator of age and dominance amongst cassowaries.
Male and female cassowaries are very similar in appearance with no obvious colour variation although females are usually larger than males and the males appear to have longer tail feathers than the females.
Newly hatched chicks are striped dark brown and a creamy white with the stripes fading between 3-6 months old and the colour changing to brown. As the young chicks mature the plumage darkens, the wattles and casque develop and the skin colour on the neck and wattles darkens. Cassowaries are mature at about the age of 3 years and there have been reports of cassowaries living 30 – 40 years in the wild and up to 60 years old in captivity.
Cassowaries are very territorial and solitary, with contact between mature individuals generally only tolerated during mating. Cassowaries use vocalizations to announce their presence to each other and thereby minimize any contact.
Cassowaries will aggressively defend their territory, which can range up to around 75 hectares if necessary. Dominance is usually decided by what is called the ‘stretch display’. This involves stretching the neck, raising the feathers, and issuing a rumbling call. If this progresses into actual conflict then the 2 birds will crash together while leaping in the air and kicking with their dagger-like inner claw. In some individuals this claw can measure up to 120mm long.
Their diet generally consists of any fruit that drops to the rainforest floor, but they will eat almost anything edible. The cassowary is active during the day and forages for food from sunrise to sunset, generally eating most in the early mornings or late afternoons.
Cassowaries eat fruit from over 150 rainforest trees, palms, cycads, shrubs, herbs, vines and epiphytes. Dominant food sources seem to include quondongs, satin ash, onion wood, white apple, walnuts, laurels and palms.
Because of their importance for plant dispersal, cassowaries are considered ‘keystone’ species, which means that the loss of them to an area could lead to long term changes to plant communities and subsequent loss of individual plant species. This is because they have primitive and relatively ineffective digestive systems, which only digest the outer flesh of fruits, and they excrete the whole seed. Since cassowaries travel such large distances dropping the seeds of a wide range of fruiting plants as they go they keep the natural balance in the rainforest.
Breeding usually occurs between June and October although chicks have been recorded from May to January. Both males and females will initiate courtship and generally mate over several weeks until all the eggs are laid. They can mate with more than one partner during a season with several females laying in the same nest.
On average 4 lustrous, olive green eggs are laid directly on the forest floor in an enclosed and sheltered area. The male over time makes a nest of leaves and sticks and incubates the eggs for about 50 days often going without food or water for long periods.
For 12 months the male takes the sole responsibility of rearing the chicks, after which time the young birds will seek out their own territory. The sub-adult mortality rate is high as opportunities to establish new homes are limited, particularly in areas where habitat has been affected.
Cassowaries blend with their surroundings extremely well as people who are lucky enough to see one in the wild will tell you. Now you see them, one step into the forest and they have disappeared into the shadows. Dung or a footprint is sometimes the only hint that a cassowary is near. The sheer size of the 3-toe footprint up to 180mm in size makes track recognition easy. The piles of dung are also very distinctive, generally about 150-200mm across filled with seeds of forest fruits and colored by the fruit skins are often a purplish brown.
Cassowary wandering through the grounds of Cassawong Cottages
Cassowaries are often seen at the rear of Cassawong Cottages at Mission Beach
Cassowary walking up the path at Cassawong Cottages Mission Beach
Cassowary with a single chick. Some males are known to raise as many as 3 chicks and are often seen foraging on the roadside.
Small chicks with the distinctive young bird striping
Note the cassowaries distinctive blue and red markings and the size of the helmet on different birds
