September is biodiversity month and you probably already know we’re big fans of biodiversity – basically the whole diversity of plant and animal life. And Threatened Species Day, which is celebrated on 7 September, takes things one step further, shining a spotlight on those plants and animals that are at risk of extinction. Australia is home to more than half a million species of plant and animal. Many of those are found nowhere else in the world. Sadly, since white settlement, more than 100 plant and animal species have become extinct.
The cassowary (Casuarius casuarius) is one of those animals in serious danger. Of the three species of cassowary in the world, only the southern cassowary (Casuarius casuarius ohnsonii) is found in Australia where it is listed nationally as endangered.
There’s no question the cassowary is an iconic bird. As tall as a person with a high helmet (casque) on its head and a bright blue neck with touches of red, it’s also easy to identify. But due to habitat decline, the bird is becoming harder and harder to spot in the wild.
Cassowaries are iconic for more than just their physical appearance.
- They really are big birds
Cassowaries are the heaviest bird in Australia and an adult stands up to 2m (6”) tall. The sexes are similar in appearance but females are slightly larger. They’re been recorded to weigh as much as 76kg but average 38kg (84lb). Males average around 47kg (104lb).
- They’re solitary, except when they mate
Generally, cassowaries are solitary birds, only coming together to mate during the breeding season which runs from May / June through to October. Cassowaries don’t form permanent bonds or mate for life and the females may mate with several male cassowaries in a breeding season. In doing so, the female bird will produce several nests, laying clutches of three to five eggs by different fathers.
- When it comes to cassowaries, dads rule the roost
Once the eggs are laid, it is the male’s sole responsibility to incubate the eggs, a process which takes around 50 days. And once the eggs hatch, males raise the chicks for a further nine months. The father teaches the young cassowaries, which have distinctive stripes to forage. They become independent at around nine months and reach maturity at around three years.
- Rainforests need cassowaries
Because cassowaries are frugivores, eating fruit that’s fallen to the ground, they’re responsible for distributing and germinating many rainforest trees. Cassowaries are considered ‘keystone’ species because of their role as a major seed disperser of up to 238 rainforest species. Without cassowaries, those rainforests would not be able to survive. It’s estimated that up to 100 plant species depend entirely on the cassowary to disperse their seeds.
When fruit is scarce, cassowaries have also been known to eat snails and small, dead mammals.
- They can do serious damage to people and other birds
People who live in cassowary territory have a healthy respect of the big bird. Their heavy, muscular legs have three toes and each toe bears a large claw up to 120mm long, whaped like a dagger and used for fighting and scratching. In the wild, cassowaries are mostly shy, avoiding contact with people but male birds can be aggressive when defending their chicks.
- Cassowaries are in serious trouble
There’s still a lot we don’t know about cassowaries, but we do know that more than 80% of coastal lowland rainforest, which is the cassowary’s prime habitat, has been cleared over the past century. And nearly a quarter of the cassowary habitat that remains has poor conservation protection. In 1998 Queensland’s Wet Tropics adult population was estimated to be up to 2,400 cassowaries strong. By 2001 scientists believed that only 1200 – 1500 wild cassowaries existed in Australia. That figure is comparable with the number of giant pandas in China. Researchers currently understand the cassowary population to be around the 4000 mark.
Rainforest Trust is working to safeguard Australia’s cassowaries by buying land in the Daintree and adding it to the National Park estate. This protects cassowary habitat and extends corridors. You can help protect cassowary habitat forever by visiting bit.ly/daintreeNP.