The Southern Cassowary, Casuarius casuarius johnsonii is listed as endangered under the Environmental Biodiversity Protection and Conservation (EPBC Act) and is found in three distinct populations within the Wet Tropics and Cape York, Queensland.
The number of cassowaries left in the wild is unclear, but estimates suggest it could be as few as 1000 in Australia.
Why is the Cassowary important?
The Cassowary is known as a “keystone” species, crucial for the preservation of rainforest diversity due to the important role it plays as a seeds disperser. Cassowaries are one of only a few frugivores that can disperse large rainforest fruits and are the only long distance dispersal vector for large seeded fruits. Their diet includes fleshy fruits of up to 238 plant species, including seven exotics.
The preservation of this species in Australia is therefore vital for maintaining the diversity of Queensland’s Far North, World Heritage Valued rainforests. (Latch, 2007)
The Cassowary is typically a solitary bird with a home range of approximately 0.5km2 to 2.5km2 depending on the season and fruit availability. The female’s home range often overlaps with a few males home ranges, whom she mates with during mating season.
The female and male cassowary often spend a month together courting and mating before the female leaves the male to incubate the 3-5 eggs for 50 days. Once the eggs hatch, the male raises the chicks until they can move into their own territory look after themselves at approximately 9 months old. Cassowaries mature at approximately 3 years old.
Mature adult Cassowaries usually only tolerate each other’s company during mating season or if there is an abundance of fallen fruit. In times where fruit has been artificially supplied on regular occasions, i.e. after cyclones, they have been known to congregate. (Latch, 2007)
These extraordinary birds grow up to two metres tall with males weighing up to 55kg and females, usually larger, up to 76kg. The adult Cassowaries body is covered in shiny black plumage and their neck and head are a distinct bright blue and purple with two red wattles and amber coloured eyes. The tall casque on the heads of mature Cassowaries grows with age, however other uses for it are unknown. Each leg has a three toes with an inside toe bearing a large dagger-sharp claw. (Latch, 2007)
The number one threat to the cassowary is habitat fragmentation and development. As the Cassowary requires such a large home range, fragmentation of their habitat forces them to roam into unsafe territory such as residential properties, across roads, into backyards and into local farm crops looking for food.
Urban development not only fragments their rainforest habitat, but it also introduces an array of threats such as roads, vehicles, dogs, human interaction, and a less resilient rainforest to climate change and cyclones. Over the past 15 years, 64 vehicle collisions have been recorded to kill as many cassowaries in and around the Mission Beach area alone. It is difficult to keep track of the Cassowary numbers as not all incidents are reported.
Unrestrained dogs pose a major threat to juvenile Cassowaries, especially once they have left their father to find their own territory. There are few reported incidents of dogs killing Cassowaries, however, it is difficult to know as many incidents go unreported.
Human interaction with Cassowaries is risky and regular interactions can encourage the birds to become less cautious of people, dogs and cars, hence leading them into unsafe circumstances.
More information on Cassowaries:
Latch. P, QLD EPA (2007) ‘Recovery Plan for the Southern Cassowary, Casuarius casuarius johnsonii’