(Casuarius casuarius johnsonii)
Do you like gardening? How about prehistoric creatures? Do you fancy eating fruits of the forest? Chances are you’ll like the Southern Cassowary, a large seed-dispersing bird from tropical Queensland, Australia.
The cassowary is Australia’s heaviest bird, weighing up to 76kg! Reaching 1.8m in height they come second only to Emus (who can reach 2m in height). Like the Emu and Ostrich, the Southern Cassowary is a ratite – a large flightless bird with unusual feathers – strong legs and other features that distinguish it from other birds due to their unique evolutionary history.
Their jet black plumage allows them to blend into their dark rainforest environment. This dense plumage is perfect for rainforest living, keeping them dry, and protecting them from thorny plants.
The cassowary’s neck is bright blue and purple. Their nape and double wattle – the pouches of skin hanging from their neck – are coloured red. Chicks are striped dark brown and white. Both sexes have a large casque or ‘helmet’ atop their heada. The outside of this protrusion is a tough keratinous material; inside it’s spongy. Its use is unclear – it may be used to push through dense rainforest undergrowth, to show age or dominance, or to detect the booming call of other cassowaries.
The cassowary is of great cultural significance to many Traditional Owner groups from north Queensland. The bird appears in traditional stories, ceremonies and dances, and was an important source of food.
Where do Southern Cassowaries live?
Cassowaries were once found across much of northern Queensland. They're now limited to three unconnected populations – one in the Wet Tropics and two in Cape York. In 2010 scientists estimated that there were only 2,500 birds left in the wild and numbers were declining.1 The species is listed as Endangered under Australian legislation, and is considered Vulnerable to extinction by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species.
Cassowaries live in tropical rainforests, melaleuca (paperbark) swamps, mangrove forests woodlands and can even be found foraging along beaches. They require this diverse range of habitats to ensure availability of fleshy fruits year round. They're capable swimmers, known to swim across rivers and into the sea to escape dog attacks. They're territorial, with a home range up to 2.35 square kilometres.
Cassowaries are frugivores (fruit eaters), and are known to eat the fruits from 238 plant species. Without cassowaries, the rainforest would be a very different place – the dispersal and germination of many plant species (especially those with big seeds) is reliant upon the bird. For this reason they're known as a 'keystone' species. They've also been called a rainforest gardener, swallowing fruit whole and spreading the seeds great distances. They also occasionally eat small vertebrates, invertebrates, fungi and carrion (dead animals).
They breed when fruit is most abundant – from June to October. The female lays three to five large green eggs in a simple nest scraped in the ground and lined with leaves. Once she's laid the eggs, the female leaves. The male then incubates the clutch for 50 days, raises and protects the chicks for about a year, and then chases them away. Cassowaries can live to 40 years in the wild.
Cassowaries make deep booming and rumbling noises, and hiss when threatened. That's when you should be 'cass-o-wary'. For such a large bird, they're quite elusive. Typically shy and solitary, they can become aggressive when threatened. Each foot has three toes, the middle toe has a long claw up to 12cm in length. Normally used to scratch for food and to fight other birds, there have been very rare instances when cassowaries have inflicted serious injuries to people and pets. The majority of these incidents are due to cassowaries searching for food from people due to a shortage of foraging habitat.
Habitat destruction and fragmentation are the main causes of the cassowary's dramatic decline. Land clearing for farming and urban development have greatly reduced their habitat. Cyclones in 2006 and 2011 also depleted their food sources, and many birds died from starvation.
After cyclones, cassowaries venture closer to human settlements, and this makes them more vulnerable to existing threats, especially dog attacks and collisions with vehicles. Road accidents are a large source of mortality. Finally, predation by feral pigs, and diseases like tuberculosis, also affect cassowaries’ survival.
What Bush Heritage is doing?
Cassowaries are found on Fan Palm Reserve, and within the Cape York Caring for Country Partnership area. On Fan Palm Reserve we’re protecting cassowaries and their food source by controlling feral pigs. In Cape York, we have supported Traditional Owner groups to plan for country using the community-led Healthy Country Planning protocols, and supported increased capacity for Aboriginal ranger groups to effectively manage outstanding biodiversity values.
1. http://www.iucnredlist.org/details/full/22678108/0 (see Garnett, S. T.; Szabo, J. K.; Dutson, G. 2011. The Action Plan for Australian Birds 2010. CSIRO Publishing, Collingwood.)