About bilbies |
Bilbies
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An extract from Tim Flannery's excellent book, Australia's Vanishing Mammals (RD Press, 1990)
BILBIES
This graceful bandicoot is quite variable in size and, depending on sex, habitat and age can weigh anything between 800 and 250 grams. It has a head and body length of 290-550 mm, with the tail adding an extra 200-290 mm.
The bilby has long, silky, blue-grey fur with white on the underside, although seasonal molts may change the coat length and the colour to a fawn-grey. Its ears are long, largely naked and rabbit-like, and it has an elongated muzzle, the last 20 mm of which are flesh-coloured and naked.
In some specimens there is a faint indication of bars across the thigh fur. The tail is first grey near its base, and then black, and ends in a sharply defined white tip. A horny spur protrudes beyond the hairs at the extreme tip and there is a crest on the upper surface of the tail. As the bilby moves with its cantering gait it often carries its tail like a stiff banner. When the animal is cantering the hind legs move together and the front legs alternatively. It usually has white feet and may have blackish tips on the claws.
The bilby has strong forelimbs and claws and it uses these to good advantage when digging for food and when burrowing. Although most bandicoots do not make burrows, bilbies dig burrows with a relatively steep spiral to a depth of up to 1.8 metres and length of three metres. The entrance is often next to a termite mound or some shrubs, and is left open. However, when it is at home, the bilby blocks the entrance with soil which extends for some distance into the burrow.
Bilbies are basically omnivorous. They eat insects and their larvae, seeds, bulbs, fruit, fungi and, in captivity, meat and small vertebrates.
Some burrows studied appear to be grouped, suggesting that the animals may live in colonies. However, investigations and reports from Aborigines show that pairs of animals and their latest offspring may inhabit each group of burrows. Home ranges may be temporary in location and shift in response to food availability. Bilbies studied in the Northern Territory were found to stay within 100 metres of their burrows, although they used and visited a number of burrows.
The sudden and widespread contraction of the bilby's range may be attributed to the effects of rabbit and livestock grazing, foxes and cats and a change in the fire regime implemented by Aborigines.
BILBIES
This graceful bandicoot is quite variable in size and, depending on sex, habitat and age can weigh anything between 800 and 250 grams. It has a head and body length of 290-550 mm, with the tail adding an extra 200-290 mm.
The bilby has long, silky, blue-grey fur with white on the underside, although seasonal molts may change the coat length and the colour to a fawn-grey. Its ears are long, largely naked and rabbit-like, and it has an elongated muzzle, the last 20 mm of which are flesh-coloured and naked.
In some specimens there is a faint indication of bars across the thigh fur. The tail is first grey near its base, and then black, and ends in a sharply defined white tip. A horny spur protrudes beyond the hairs at the extreme tip and there is a crest on the upper surface of the tail. As the bilby moves with its cantering gait it often carries its tail like a stiff banner. When the animal is cantering the hind legs move together and the front legs alternatively. It usually has white feet and may have blackish tips on the claws.
The bilby has strong forelimbs and claws and it uses these to good advantage when digging for food and when burrowing. Although most bandicoots do not make burrows, bilbies dig burrows with a relatively steep spiral to a depth of up to 1.8 metres and length of three metres. The entrance is often next to a termite mound or some shrubs, and is left open. However, when it is at home, the bilby blocks the entrance with soil which extends for some distance into the burrow.
Bilbies are basically omnivorous. They eat insects and their larvae, seeds, bulbs, fruit, fungi and, in captivity, meat and small vertebrates.
Some burrows studied appear to be grouped, suggesting that the animals may live in colonies. However, investigations and reports from Aborigines show that pairs of animals and their latest offspring may inhabit each group of burrows. Home ranges may be temporary in location and shift in response to food availability. Bilbies studied in the Northern Territory were found to stay within 100 metres of their burrows, although they used and visited a number of burrows.
The sudden and widespread contraction of the bilby's range may be attributed to the effects of rabbit and livestock grazing, foxes and cats and a change in the fire regime implemented by Aborigines.
An extract describing the two types of bilbies from Raymond Hoser's beautifully presented book, Endangered Animals of Australia (Pearson, Sydney, 1991)
GREATER BILBY Macrotis lagotis Reid 1837
SIZE (mm) TAIL LENGTH (mm) WEIGHT (grams)
Males 500-840 200-290 1000-2500
Females 490-670 200-280
800-1100
IDENTIFICATION: Light, delicate build and fine, silky soft fur. Long, rabbit-like ears, long pointed muzzle. Hindfoot lacks first toe. This species may be differentiated from the Lesser Bilby M.leucura by its tail, which is black and white with a prominent crest, with the extreme tip naked. The tail of the Lesser Bilby has white fur along the entire upper surface of the tail, with black on the underside of the proximal two-fifths. The Greater Bilby also differs from the Lesser Bilby in its larger adult size.
DISTRIBUTION: Mainly confined to desert areas of Central Australia, with outlying populations in the Kimberley and Warburton regions of Western Australia, and near the Birdsville area in far south-western Queensland. Around 1900, the Greater Bilby was found in drier areas of all the mainland states.
HABITAT: Varied, but present populations principally occur in hummock grasslands and acacia shrublands with spinifex or tussock grass.
NUMBER LEFT: Probably a few hundred.
PRINCIPAL ACTION REQUIRED: As it is probably only a matter of time before all wild populations of this species are eliminated, captive breeding colonies are essential.
LESSER BILBY Macrotis leucura Thomas 1887
SIZE (mm) TAIL LENGTH (mm) WEIGHT (grams)
Males 365-440 125-170 397
Females 320-390 120-150 311
DISTRIBUTION: The Lesser Bilby has only been recorded on six occasions, all in deserts of north-eastern South Australia and the south-eastern Northern Territory.
HABITAT: The Lesser Bilby was last reported alive in 1931 near Cooncherie in north-eastern South Australia, where it was considered to be reasonably common. Its habitat was sandhills, where free surface water was rarely available. The Greater Bilby, known in the same area, burrowed on the loamy flats between the sand dunes.
STATUS: Endangered, possibly extinct. In 1967 a skull from this species, of unknown age, was found in a Wedge-tailed Eagle's nest, south-east of Alice Springs near the Simpson Desert.
CAUSES OF CURRENT STATUS: Presumably the same as for the Greater Bilby: principally the introduction of rabbits and foxes.
PRINCIPAL ACTION REQUIRED: An active search of areas where the Lesser Bilby may still occur. If specimens are found, they should be caught in numbers sufficient to establish captive colonies to pre-empt their extinction in the wild.
GREATER BILBY Macrotis lagotis Reid 1837
SIZE (mm) TAIL LENGTH (mm) WEIGHT (grams)
Males 500-840 200-290 1000-2500
Females 490-670 200-280
800-1100
IDENTIFICATION: Light, delicate build and fine, silky soft fur. Long, rabbit-like ears, long pointed muzzle. Hindfoot lacks first toe. This species may be differentiated from the Lesser Bilby M.leucura by its tail, which is black and white with a prominent crest, with the extreme tip naked. The tail of the Lesser Bilby has white fur along the entire upper surface of the tail, with black on the underside of the proximal two-fifths. The Greater Bilby also differs from the Lesser Bilby in its larger adult size.
DISTRIBUTION: Mainly confined to desert areas of Central Australia, with outlying populations in the Kimberley and Warburton regions of Western Australia, and near the Birdsville area in far south-western Queensland. Around 1900, the Greater Bilby was found in drier areas of all the mainland states.
HABITAT: Varied, but present populations principally occur in hummock grasslands and acacia shrublands with spinifex or tussock grass.
NUMBER LEFT: Probably a few hundred.
PRINCIPAL ACTION REQUIRED: As it is probably only a matter of time before all wild populations of this species are eliminated, captive breeding colonies are essential.
LESSER BILBY Macrotis leucura Thomas 1887
SIZE (mm) TAIL LENGTH (mm) WEIGHT (grams)
Males 365-440 125-170 397
Females 320-390 120-150 311
DISTRIBUTION: The Lesser Bilby has only been recorded on six occasions, all in deserts of north-eastern South Australia and the south-eastern Northern Territory.
HABITAT: The Lesser Bilby was last reported alive in 1931 near Cooncherie in north-eastern South Australia, where it was considered to be reasonably common. Its habitat was sandhills, where free surface water was rarely available. The Greater Bilby, known in the same area, burrowed on the loamy flats between the sand dunes.
STATUS: Endangered, possibly extinct. In 1967 a skull from this species, of unknown age, was found in a Wedge-tailed Eagle's nest, south-east of Alice Springs near the Simpson Desert.
CAUSES OF CURRENT STATUS: Presumably the same as for the Greater Bilby: principally the introduction of rabbits and foxes.
PRINCIPAL ACTION REQUIRED: An active search of areas where the Lesser Bilby may still occur. If specimens are found, they should be caught in numbers sufficient to establish captive colonies to pre-empt their extinction in the wild.
Reference Books
Some good reference books on the bilby and other Australian animals include:
Australia's Vanishing Animals
Flannery, T., Kendall, P. Wynn-Moylan, K. (RD Press, Surrey Hills, NSW, 1990) |
Endangered Animals of Australia
Hoser, R.T. (Pierson & Co, Sydney, NSW, 1991) |
An Illustrated Encyclopedia of Australian Wildlife
Morcombe, M. (Treasure Press, Port Melbourne, Vic, 1989) |
The Australian Museum Complete Book of Australian Mammals
Strahan, R. [Editor] (Cornstalk Publishing, North Ryde, NSW, 1991) |