Emus and Cassowaries
Information and images.
from Australian-Wildlife.com
Emu
and cassowaries are the last remaining endemic large, flightless
birds in Australia. Ostriches are also found here but are exotic,
having been introduced for feather farming and having subsequently
found there way into the wild.
Emus
The
Emu, Dromaius novaehollandiae, (fast-footed New Hollander) is the
largest surviving native bird in Australia. It is found across almost
all of mainland Australia but is rare in settled areas. It is mainly
found in open woodland and plains. The ratite group, to which they
belong, has been around for at least 80 million years.
Physical description
Emus
are large birds, the largest indigenous birds in Australia. The
can stand up to 2m tall (6.5 feet) and can weigh up to 55Kg (120lb).
They are predominantly brown in colour with a white base to the
feathers. This adaptation allows for convection cooling from the
tips of the feathers, thus allowing foraging right through the hottest
part of the day. The feathers are unique in that they have a double
rachis emerging from a single shaft. Also the feathers have non-interlocking
barbs, something which is not necessary for flightless birds. The
back of the neck is free from feathers and has a bluish tinge.
They have soft, broad beaks, designed for foraging, large eyes capable
of seeing large distances, and powerful three-toed feet. They will
walk almost constantly when awake (and not on the nest, of course)
and can cover 10-25km per day.
Emus are strong swimmers and are happy to cool down by lying in
a stream.
Reproduction
Breeding
takes place in the cooler months and is instigated by the male.
He will build a rough nest in a shallow hollow and then begin mating
with a female. They will continue to mate every day or two and every
second or third day a single large, thick shelled egg is laid This
will continue until 9-12 eggs have been laid, although in a good
season this number may reach 20. After the 5th or 6th egg has been
laid the male will become broody and mating will cease. At
this time the female will continue to mate with other males and
will continue to lay eggs in the first nest.
For the next 8 weeks the male will incubate the nest, never leaving
to eat drink or defecate and only standing to turn the eggs. During
this time he will lose approximately a third of his body weight,
surviving only on what dew and seeds can be reached from the nest.
Predation of the eggs is high, mainly from goannas (lace monitor
lizards).
The hatchlings are around 25cm (10in) tall and are brown with cream-coloured
stripes. They are able to leave the nest after only two or three
days.The male will stay with the chicks for at least six months.
Without this attention the chicks do not learn how to feed themselves.
The chicks are fully grown at twelve months.
Ecology
and behaviour
Emus are nomadic foragers, following the rains and feeding on grains,
flowers, fruit, soft shoots, insects, grubs, and whatever else is
available. They swallow stones to aid digestion. They are almost
constantly walking and are able trot for large distances or sprint
for shorter distances at up to 50kph. They require water daily.
Emus and man
The
number of emus in the wild has grown significantly since the arrival
of European settlers due to improved pasture and the availability
of water from dams. They have regularly been viewed by the farming
community as pests.
Since 1994 all Australian states have been permitted to raise emus.
They are farmed for their meat, their oil and their leather. However,
the industry has not grown in the manner many expected and many
farms and slaughterhouses have closed.
Main sources for this information:
Wikipedia
Birds of Australia, Slater et al.
http://eggcrazy.com/emuinfo.html
http://www.oaklandzoo.org/atoz/azemu.html
Cassowaries
Three
species of cassowary are still in existence, one of which, the Southern
Cassowary (casaurias casaurias), is found in Australia's far north
in the tropical forests of Queensland. It is classified as vulnerable
due to habitat loss.
Physical
description
Cassowaries
are large flightless ratites and at 1.8m (5 1/2 feet) tall are amongst
the largest birds on earth. They can weigh a maximum of 60kg (130lb),
have drooping black plumage with brightly coloured blue necks and
have bright red wattles. They have a bony casque, or helmet, on
top of the head (purpose uncertain, although it has been observed
using it for pushing aside forest littler looking for food) making
them the only armoured birds in the world. They are also known for
the sharp claws on their three toed feet, with which they have been
known to kill an enemy (including man) with a single, disemboweling
kick. They can run at up to 50kph, can jump 1.5m from a standing
position and are capable swimmers. Females are marginally bigger
than males. Life span 40-50 years.
Reproduction
Cassowary
reproduction is very similar to that of the emu, to whom they are
closely related. Individuals tend to live solitary lives but come
together in the breeding season. Males will stake a territory and
will build a nest. He will mate with the female and she will lay
3-5 eggs. Thereafter she will mate with other males whilst he tends
the nest and then the chicks.He will remain with the chicks for
at least the first 9 months. The eggs are incubated for two months.The
chicks are brown with cream-coloured stripes.
Ecology and behaviour
Cassowaries
live in forests where they forage for fruit from the ground. They
will also eat fungi and small animals.
Cassowaries and man
Cassowaries are known as the most dangerous birds on Earth. Despite
this tag there are relatively few documented cases of attacks on
man, although these attacks can easily be fatal. Cassowaries are
very shy birds and will almost always run away from contact with
humans (making them very difficult to study). Attacks are most common
when provocation is involved or when a male is protecting the nest
or young.
Cassowaries have been traded for feathers and food for possibly
500 years, mainly in Papua New Guinea.
The destruction of the rainforest, their natural environment, is
the major threat to their survival since they require large expanses
of unbroken forests to adequately survive. They are also threatened
by the hunting trade and by cars.
Habitat loss has caused some birds to venture out of the forest
looking for food. This has caused conflict with fruit growers.
Main sources for this information:
http://animaldiversity.ummz.umich.edu/
wikipedia
Australian birds, Slater et al
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