Known as ‘rainforest gardeners’ Southern Cassowaries eat fruits whole and spread seeds great distances. Our tropical forests would be very different without them.

The Southern Cassowary is a large seed-dispersing bird found in Indonesia, New Guinea and tropical Queensland.

Two related species – the Dwarf Cassowary and Northern Cassowary – can be found in New Guinea and Indonesia.

Many plant species (especially those with big seeds) rely on Southern Cassowaries for seed dispersal and germination. For some, there are no other animals large enough to swallow and disperse them, and other seeds rely on the cassowary's digestive process to germinate.¹

The cassowary is Australia’s heaviest bird, weighing up to 76 kg! Reaching 1.8 m in height they come second only to Emus (which can reach 2 m).

Like the Emu and Ostrich, the Southern Cassowary is a ratite – a large flightless bird with unusual feathers, strong legs and other distinguishing features that point to its unique evolutionary history.

Fan Palm canopy at Fan Palm Reserve - Southern Cassowary habitat.

Fan Palm canopy at Fan Palm Reserve. Photo Craig Allen.

Where do Southern Cassowaries live?

While the Southern Cassowary (Casuarius Casuarius) is found in New Guinea, one subspecies – Casuarius casuarius johnsonii – lives in Australia. This southern cassowary subspecies is listed as Endangered under the Environment Protection and Biodiversity Conservation Act 1999.

Cassowaries were once found across much of northern Queensland. They’re now limited to isolated populations in the Wet Tropics and Cape York.

However, globally, the International Union for Conservation of Nature (IUCN) has lifted the status of Southern Cassowaries (Casuarius casuarius) from Vulnerable to of Least Concern.

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 all 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.

Behaviour of cassowaries

Cassowaries are frugivores (fruit eaters), and are known to eat the fruits from 238 plant species.

Many species rely on cassowaries for seed dispersal and germination. For this reason they’re known as a ‘keystone’ species. They’ve also been called rainforest gardeners, swallowing fruit whole and spreading seeds great distances. Their dung provides a ready-made fertiliser to help the seeds sprout.

Cassowaries also occasionally eat small vertebrates, invertebrates, fungi and carrion (dead animals).

Southern Cassowary scat. Photo Nic Gambold.

Southern Cassowaries 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. For such a large bird, they’re quite elusive. Typically shy and solitary, they can become aggressive when threatened and have been called the world's most dangerous bird.¹

Each foot has three toes and the middle toe has a long claw up to 12 cm 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.

A father Southern Cassowary with chicks.

Threats to Southern Cassowaries

Habitat destruction and fragmentation are the main causes of the cassowary’s dramatic decline. Land clearing for farming and urban development has 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 such as tuberculosis, also affect their survival.

What’s Bush Heritage doing?

Our Fan Palm Reserve in far north Queensland was rescued from developers in 1993 and provides excellent habitat for Southern Cassowaries in the wet tropics. As well as protecting the mesophyll vine forest, we control the potential for Lantana infestation around the fringes of the reserve and control feral pigs that damage the ecosystem.

(see also Garnett, S. T.; Szabo, J. K.; Dutson, G. 2011. The Action Plan for Australian Birds 2010. CSIRO Publishing, Collingwood.)

Southern Cassowary. Photo Steve Parish.

You can help

Contribute to a future where Australia's extraordinary natural landscapes are protected and unique Australian species, such as the Southern Cassowary, have suitable habitat.

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