Australia’s Biggest Birds-A Keystone Species and A Cultural Icon

Southern Cassowary(from the Malay name kasuari) or double-wattled cassowary, Casuarius casuarius, found in southern New Guinea, northeastern Australia, and the Aru Islands, mainly in lowlands.
Southern Cassowary(from the Malay name kasuari) or double-wattled cassowary, Casuarius casuarius, found in southern New Guinea, northeastern Australia, and the Aru Islands, mainly in lowlands.

In honor of celebrating cassowaries and their friends on World Cassowary Day on 26 September 2016 in Australia.  Today is the day to wear the colors of a Cassowary, which are red, blue, and black.  These are very important icons of Australia and deserve a day of recognition to their contribution of spreading plant life throughout the rainforests and being a significant species through the northern part of Australia.

 

Cassowaries are part of a species of birds known as “ratites”.  They are called such because they are flightless birds who lack a keel on their sternum.

Distribution of Australia's Cassowary.
Distribution of Australia’s Cassowary.

They are part of the genus Casuarius and are native to the lush, tropical, forests of New Guinea, nearby islands, and northeastern Australia.  There are also three extinct species.  The most common is species is the southern Cassowary, which is the third tallest and second heaviest living bird.  They are smaller than the ostrich and the emu.  Northern Australia, humid rainforests, and the nearby small islands are home to the Cassowary. They will often venture out into swampy forests, grasslands, palm scrub, and savannas, but it is unclear if some of the islands populations of the birds is because of trade or if they naturally originate there.  For the purpose of this piece, we will only be talking about the southern Cassowary, unless otherwise indicated.

Though the species are truly omnivorous, their diet consists mainly of fruits(called frugivores), as well as a variety of other foods including fungi, insects, frogs, flowers, snails, fish, birds, mice, rats, carrion, shoots, and grass seeds as well as small invertebrates and vertebrates.  Some important fruits of their diets are nightshades, wild grape, palm, myrtle, laurel, and podocarp.

Cassowary Plume & Flower
Cassowary Plume & Flower

Since the Cassowary eat whole fruits and the redistribute the seeds through their excrement wherever they go, they have been considered a keystone species of the jungle.

The Cassowaries are usually a shy creature, but when provoked, they are very dangerous and can inflict fatal injuries onto humans and dogs.

As well as being shy, these birds are also very elusive.  They are able to disappear into the forests before they are seen by humans.

The female Cassowaries are larger and display brighter colors than the males.

Cassowary Skull
Cassowary Skull
Southern Cassowary Color Diagram
Southern Cassowary Color Diagram

Adult Cassowaries generally from 4.9ft-5.9ft tall, although it has been recorded that some females may reach a height of 6.6ft.  Females can weigh up to 129lbs, while males can weigh up to 75lbs.  40-50 years is thought to be the lifespan of a Cassowary in a zoo, whereas only 12-19 in the wild.  They major in 2 1/2 to 3 years of age.

Cassowary Feather
Cassowary Feather

The Cassowaries feathers consist of a shaft and have loose barbules.  They lack a preen gland and tail feathers.  Their small wings have 5-6 remerges that are reduced to keratinous, stiff quills, similar to a porcupine’s quills, but without the barbs on their tiny wings.  It is thought that their wedged-shaped body is shaped this way as an adaption to push through the vines and sharp leaves through the bush and the rainforest.

The inner toe is formed into a long dagger-like claw that can be a formidable weapon.
The inner toe is formed into a long dagger-like claw that can be a formidable weapon.

On each second finger on both feet, the Cassowaries have a claw.  Their dagger-like claw on their foot, in the medial position, is 5 inches in length.  It can be used as a lethal weapon when a Cassowary kicks its powerful legs out in defense.  With these legs, they’re able to run up to 45mph in the dense forests of Australia.  They are

A pair of Cassowaries take a stroll on a beach.
A pair of Cassowaries take a stroll on a beach.

excellent swimmers, able to cross wide rivers and swim in the sea plus they can jump up to 5 feet high.

Two of the three cassowary species have wattles, or bare, fleshy pouches of skin

Wattle of a Southern Cassowary
Wattle of a Southern Cassowary

that hang from the neck: southern or double-wattled cassowaries and northern or single-wattled cassowaries. The wattles are brightly colored blue, red, gold, purple, or white, depending on the species or subspecies. It is thought that the wattles are to help show the bird’s mood or relay other social cues known only to the cassowaries.

The casque starts to develop on top of their head at one to two years of age. The casque is made of a sponge-like material and covered with a thick layer of keratin, the same thing our fingernails are made of. Although it is quite sturdy, the casque can be squeezed in the middle fairly easily.
The casque starts to develop on top of their head at one to two years of age. The casque is made of a sponge-like material and covered with a thick layer of keratin, the same thing our fingernails are made of. Although it is quite sturdy, the casque can be squeezed in the middle fairly easily.

A spongy, horn-like but soft crest called casques sits atop every three species of a Cassowary’s head.  Several theories have been proposed for the purpose of the casque.  One theory suggests that it helps them plow through the underbrush of the dense forests.  Another says that it is used as a weapon in battle.  Still another theory says it is a secondary sex characteristic.  Some other speculations say that it is used to push aside leaves and other debris whilst foraging, as a weapon, and to help maneuver through the underbrush.

Most of theories have been disputed. Biologist Andrew Mack has disputed the last three theories.  Through his personal observations, he hypothesizes that the casque amplifies deep sounds.

An earlier article published prior to Andrew Mack’s theory suggests that the casque might be a form of protective headgear because whilst charging through the forest they run into trees.  Cassowaries also spend a lot of time under trees, foraging for seeds and wild fruits, where seeds the size of golf balls from over 10 feet high, where the casque would protect their heads by deflecting the fruit.

Cassowaries maintain a solitary life, except when laying eggs, during the breeding, and occasionally around ample food sources.

The territory of a Cassowary is about 1700 acres for a male, which he will defend for him and his mate.  There are usually several females whom overlap the territory of a single male.  The females may move between territories to mate with the same male or several related males during their lifetimes, but they will generally stay with one male in the same territory their whole life.

 

Cassowary eggs come in different colors. They are also the second smallest only to Emu eggs
Cassowary eggs come in different colors. They are also the second smallest only to Emu eggs

The breeding season begins in May or June, where the female will lay a clutch of three to eight eggs, bright green or pale green-blue eggs in color in a prepared heap of leaf litter.  The eggs measure 3.5in.  x 5.5in.  An egg can weigh up to 20 ounces.  The eggs of an ostrich and an emu are the only bigger eggs.  The female will then go on to lay eggs in the nests of other males.  The male will then incubate the eggs, maintaining a constant temperature for 50-52°F by painstakingly removing or adding leaf litter to regulate this temperature.  After the eggs hatch, he then maintains sole responsibility and vigil of protecting and rearing those brown-stripped chicks for nine months.  He will fiercely protect them from all potential predators, including humans as well as other animals.  After those nine months, those young males will go off to find a territory of their own.

The meat of the Cassowary is quite tough.  It is said that you are to cook it with a stone.  When the stone is ready to eat, so is the Cassowary.

The southern Cassowary is in decline and in is endangered in Queensland,

Southern Cassowary
Southern Cassowary

Australia.  Only about 20%-25% remain.  Loss of habit is a major contribution to this decline.  55%% or 140 cases of mortality were accounted for by automobile fatalities.  5 cases were from hunting, 1 was from being entangled by wire, and 4 had to be euthanized for they had attacked humans.  Natural causes included 4 cases of tuberculosis, general natural causes, and 18 cases were from unknown circumstances.

When Cyclone Yesi destroyed a large part of a Cassowary habitat in 2011, 200 birds were endangered, which accounted for 10%% of Australia’s Cassowary population.

Aborginal PiecesSome of the Highland Societies in New Guinea capture Cassowary chicks to raise them as semi-tamed livestock or for use as ceremonial gift-exchanges and for food.

 

 

 

 

Feather Profile 8x11

 

In folklore, Cassowaries have had a reputation for being dangerous to both humansCassowary Clip Art and domestic animals.  Australian troops stationed near New Guinea during WWII were warned to stay far away from them.  In 1958, Ernest Thomas Gilliard, an ornithologist, wrote in his book, “Living Birds of the World”: “The inner or second of the three toes is fitted with a long, straight, murderous nail which can sever an arm or eviscerate an abdomen with ease.  There are many records of natives being killed by this bird.”

Gregory S. Paul backed up this claim again in print in 1988, as well as Jared Diamond in 1997.  150 Cassowary attacks were against humans in 2003.  75% was because humans were feeding Cassowaries.  71% of the time the Cassowary charged or chase the victim.  15% of the time they were kicked.  Of these attacks, it was because the bird was snatching or expecting food.  Natural food sources were being defended 5% of the time.  The Cassowary was defending themselves 15% of the time from attacks.  Defending their eggs or chicks was account for 75 of the time.  In all the 150 attacks, there was only 1 human fatality.

On April the 6th, 1923, two brothers, aged 13 and 16, found a Cassowary on their property.  They decided to strike it maliciously with clubs to kill it.  The bird managed to kick the younger boy, who ran away.  Whilst the older brother continued to club the bird, he tripped and fell to the ground.  Whilst he was on the ground, the Cassowary was able to kick the boys’ neck, ripping open a .49 inch wound, which may very well have been his jugular vein.  The boy died shortly afterwards from him his injuries.

Very rarely do Cassowaries strike in the abdomen.  There is but one case in which a dog a dog who succumbed to such an injury in 1995.  There was no puncture wound, but severe bruising, but the dog later passed away from an apparent intestinal rupture.

The casque could also work much like a hornbill’s casque does in helping the bird make sounds. The Cassowaries can produce very low-frequency sounds, called booms, that help them communicate through the dense rain forest, so perhaps the theory that Andrew Mack proposed that says casque helps with that in some way. Females tend to have a larger casque than males.

Cassowaries also hiss and whistle to communicate, and clap their bills or rumble when making a threat. The rumble is so low and powerful that keepers working with the birds report they can feel it in their bones.

In Australia, most of the remaining habitat of the southern cassowary is now located within protected areas. A recovery plan for the species has been drawn up by the Queensland Parks and Wildlife Service, with the aim of securing and enhancing the status of the southern cassowary in Australia through integrated conservation initiatives.  In New Guinea, further data on population numbers is required and hunting restrictions may need to be imposed. This awesome bird belongs to an ancient lineage and is one of the most striking of the flightless birds; its conservation has important cultural and ecological significance.

front of Cassowary card

Cassowaries need help to survive

back of Cassowary card

 

View information on this species at the UNEP World Conservation Monitoring Centre.

To help conserve this species by working in the field with Earthwatch, click here.

Find out more about the Southern Cassowary and its conservation:

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