Winter 2002
KILLER CATS

 

by

Kerry Sharp

 

The feral cat is a highly skilled predator with the ability to survive against the harshest odds.    Researchers believe the Northern Territory's feral cat population exceeds 100,000 which notch up a staggering annual kill of more than 36.5 million (36,500,000) small native animals.

 

The early ocean travellers to Australia unwittingly sowed the seeds of an environmental tragedy when they brought their pet cats ashore.

 

The subsequent escape or deliberate release of domestic cats led to free living populations that now occupy the entire Australian continent and most of our offshore islands.    In contrast to the milder mannered domestic version, the feral cat is now ravaging the Australian bushland and literally eating the heart out of our native fauna.

 

To date their has been little research into the feral cat but the growing body of evidence shows that Australia's native fauna would now be in greater numbers with fewer extinctions if the pet cats of the earliest travellers had never reached our shores.    Australia's native fauna is paying the tragic price since the arrival of Europeans about 200 years ago.    More than 30 percent of the Northern Territory's desert dwelling small mammal species have been wiped out along with several bird species.    The feral cat appears to have played a hand in these extinctions.

 

Felis catus has been prowling the Northern Territory bush for at least 100 years.    No one knows for certain when it came but it was already here in appreciable numbers last century when some of the earliest European expeditions began moving into this part of the country.

 

In 1883, the geologist George Winnecke observed a feral cat near the Queensland border in an area now encompassed by remote Tobermorey Station.    Later in 1897, British adventurer and prospector, David Carnegie, while travelling south east from Halls Creek to Coolgardie via the Northern Territory - Western Australia border area, came across two Aboriginal women hunters at Winnecke Hills, 500km west of Alice Springs, with a common domestic black cat, evidently just killed among their takings.

 

When Charles Chewings led a well-sinking expedition through the Tanami Desert in 1909, he found an abundance of feral cats, so plentiful where they that he referred to one region as "cat country".

 

Feral cats seen at those times had colonised the country independently of humans.    Within two decades of Europeans settling the Northern Territory, feral cats where many hundreds of kilometres from the nearest towns and outstations.

 

Various theories have suggested feral cats originated from early shipwrecks along the Western Australian coast, from the Macassans sailing south to trade with Top End Aborigines, or that they were ancestors of the domestic cats brought north by the Overland Telegraph Line construction gangs.    Whatever their origins, feral cats have adapted astonishingly well to our bushlands to become one of this country's most efficient and skilful hunters in the wild.

 

Feral cats are robust creatures with the ability to survive in the most inhospitable conditions.    They are now scattered the length and breadth of the Northern Territory with large populations occurring in a diverse range of habitats.    They occur throughout the hot dry spinifex deserts of central Australia, the rugged Kimberley Ranges, the Arnhem Land Wetlands and the steamy mangrove and rainforests of the tropical north.    They also survive in the streets and alleys of our towns and cities.

 

"They are the most extraordinary colonisers." says Dr. Ken Johnson who, as head of the Conservation Commission's Mala research program in Central Australia, has tasted the bitter disappointment that goes hand in hand with feral cat power.

 

"I've been working in the Tanami where our weather station was recording daily temperatures of 45 degrees, yet the cats were comfortably surviving without water other than the moisture they got from mammals, birds and reptiles they killed at night."

 

Feral cats are most often seen at night.    By day they tend to hide away in rabbit burrows, hollow logs or other convenient shelters to escape the heat of the day and to gather strength for the nocturnal carnage. 

 

Legend has it that wild cats as big as tigers are prowling the Australian bush, but legend is wrong.    The feral cat is rarely bigger than your average domestic cat but its stealth and speed are just as chilling as those of the tiger.    Little wonder that the feline king's pint sized cousin has earned itself such an ugly reputation.    Very large cats have been reported on odd occasions, but generally males weigh an average of 4kgs and females are around 3kgs.    The vast majority of the Northern Territory's feral cats are tabby in colour with orange being the next most predominant shade.    These colours probably offer the best camouflage for cats trying to hunt down their prey.

 

Depending what is available; the feral cat will feed on live insects, fish, frogs, reptiles, birds and native and introduced mammals up to the size of a Brush-tail Possum.    Rabbits constitute a major food source in Central Australia.    Cats can kill prey up to their own body size - that puts most of Australia's endangered and vulnerable mammals, birds and reptiles in danger.    Already there is evidence of their dramatic impact on the Bilby and Rufous Hare-wallaby or Mala.

 

These adept predators are known to prey on more than 100 native bird species, 50 mammals, 50 reptiles, a number of amphibians and a number of invertebrates.    The list continues to grow as more data comes to light through wildlife research programs. 

 

Urban trends have done little to help the situation.    The blame cannot be placed solely with the unfortunate animals discarded by their owners to fend for themselves in the bush.    Surveys show that one in every three Australian household keep a domestic cat and, despite sufficient food supplied by the owners, their pets bring home an average five to ten mauled native birds every year.    It is estimated that in big cities like Melbourne, millions of native birds are killed annually by cats whose predatory activities account for most of the fledglings bred in suburbia each year.    Larger natives such as possums also die in their thousands every year at the hands (or paws) of the domestic cat.

 

There must be more than 100,000 feral cats roaming the Northern Territory bush (i.e. one cat for each 13 square kilometres).    But even with this very conservative figure and the equally conservative figure of one animal killed each day, it still works out to a staggering 36.5 million native animals killed each year.

 

The number is undoubtedly much higher.    One cat in the Tanami Desert was found to have eaten a marsupial mouse, a native rodent, a bird, two lizards and the front half of a large goanna.    A cat on an island off Western Australia had devoured an entree of no fewer than nine mice before 10 o'clock at night.

 

In May last year, the Endangered Species Unit of The National Parks and Wildlife Service hosted a national workshop in Canberra to look at the impact of feral cats on Australia's native fauna.    There was no argument among participants that cats represented a significant threat to fauna.    The clear message was that urgent studies were needed to find ways to remove the threat.    A major recommendation was that an expert working group, comprising representatives of Federal, State and Territory nature conservation agencies and the CSIRO, be established to target the country's feral cat dilemma.    The group's priority task will be to develop a national research strategy to better gauge the impact of feral cats on native flora and fauna and ecosystems, and to identify ways to tackle it.

 

Dr. Johnson and his team are working on a captive breeding program which one day is expected to see wild populations of the Mala or Rufous Hare-wallaby, one of Australia's most critically endangered native mammals, re-establish in places where it had become extinct.    The Mala once occupied about 25% of mainland Australia, from the Northern Territory's western spinifex deserts and the North West regions of South Australia, through to Western Australia's vast spinifex sand dune country and to the drier wheat belt area east of Perth.

 

Today there are no known wild Mala colonies left on the Australian mainland.    Until recently there were two discrete but neighbouring populations surviving in the Tanami Desert but one was extinguished in 1987 in association with a single fox.   

 

The other was destroyed by wildfire in 1991.    Fortunately a captive colony has been established in Alice Springs and this now forms the basis of a project to re-establish free living wild populations.    Significant Mala populations still exist on protected Dorre and Bernier Islands off the Western Australian coast.    These wallabies are of the same genus and species as the mainland Mala, but they are much bigger darker in colour and being without natural predators are very quiet compared with their skittish mainland cousins.

 

Attempts to reintroduce captive bred Mala into their former natural habitat in the Tanami Desert during late 1990 suffered an unexpected setback.    The timid creatures were slaughtered by feral cats some months after they had tentatively felt their way back into the wild and established a breeding population.

 

"That's when the research team began finding the partially eaten bodies of Mala that had been released into the wild from the special desert enclosure three months earlier." Dr. Johnson said.

 

Please click on thumbnails to enlarge

These are recent pictures of a geriatric Mala (a known 14 years old) at the National Parks and Wildlife facility at Monarto, South Australia

"The Mala had successfully established in the wild and had raised young over the three months before the trouble started.    Careful monitoring of the area and assistance in tracking by local Warlpiri people from Willowra showed there to be no dingoes or foxes but several cats in the release area and that the cats were responsible for the deaths.    I was aware that cats were killers of our native fauna but I had not expected them to be so devastatingly efficient."

 

"It has, nevertheless, been an indisputable demonstration that feral cats present a serious threat to the conservation of native fauna, and it has helped to start the national program to solve the problem."

 

Disappointed but undeterred, the Conservation Commission research team has initiated further releases in the Tanami since that discovery, determined to learn from past failures by adopting methods that could eliminate the threat.    As a result of the ongoing Northern Territory Mala research effort, there are now 50 healthy, captive bred animals being held at Alice Springs, at least 60 in a 1sq km enclosure at the Lander River flood-out north of Willowra in the eastern Tanami Desert, with 27 free ranging from that site, and a further 11 near Sangsters Bore in the southern Tanami.

 

As masterly as they are at the art of stealth and predation, feral cats do not have it all their own way in the Territory bush.    Dingoes eat them when they can catch them and Central Australian Aborigines historical have regarded them as an easily attained food source, especially in the summer months when the felines could be tracked down to their daytime refuges from the searing desert heat.    The cats, disease carriers themselves, also must contend with life threatening blights like bronchitis and pneumonia and with a whole range of parasites.    Now they face the added threat from wildlife researches who are determined to find acceptable methods for controlling feral cat populations.

 

A Conservation Commission researcher, Geoff Lundie-Jenkins, who works on the Central Australia Mala project at Sangsters Bore, says there are no suitable techniques available for combating the cat over vast regions of the Northern Territory.   "The use of poisoned baits has been successful in reducing the numbers of dingoes on pastoral lands, but cats are reluctant to accept such offerings of free food.    Our desert cats in particular tend to snub the type of food available to their counterparts in urban areas.    They are used to fending for themselves by living off bush resources and they favour live prey like small mammals and birds rather than canned food or pieces of meat.    Conversely, feral cats inhabiting urban areas are more partial to favour meat and household scraps."

 

"We have had success in working with local Aboriginal people to track down cats to where they can be shot, but this is very labour intensive and not a viable solution for large areas.    Survival of the Mala since these controls have been introduced has nevertheless shown the worth of such effort."

 

Geoff Lundie-Jenkins says Northern Territory circumstances are significantly different to those in densely populated areas of Australia.    While the Territory has appreciable cat populations, the opportunities for control are hampered by limited manpower and by the animals' spread over such a vast and remote area.    He says there is a real urgency for feral cat research in this region because of the race against time to keep more valuable wildlife species off the extinction list.

 

Prompted by the concerns of the nations' leading feral cat authorities at last year's Canberra workshop, the Australian National Parks and Wildlife Service has allocated substantial funding for feral cat research in the next financial year.    This will significantly assist the existing studies of feral cats.

 

"It is imperative that we increase our research effort to find appropriate methods for controlling cats so that we can get substantial colonies of our endangered species back thriving again in their former wild habitats." Geoff Lundie-Jenkins says.

 

In the arid mainland desert the best chance of victory, in the short term, appears to be in the intensive methods of control so that captive bred animals like the Mala can build up wild populations to a stage where they have strength to withstand introduced ravages.    A corresponding all out offensive against the feral cat with weapon yet undiscovered, may see once threatened native species thriving again in the wild.

 

Since September last year, Mala released from their enclosure on Lander River have all survived.    This has been due to a concentrated effort of trapping and shooting cats in the vicinity, thereby eliminating many potential predators.     Recently researchers felt their efforts were being rewarded when they trapped a female Mala that had been raised to independence by her mother after release from the enclosure.    She was carrying her own pouch young.

 

The Conservation Commission has high hopes for the success of the Mala program but recognises that there is still a long way to go and a lot more to learn before the feral cat is finally eliminated as a threat to vulnerable native fauna.   That day will mark the beginning of a very substantial recovery of Australia's native fauna.

 

(This article is printed with acknowledgments to Nature Territory and the author and was first printed in ‘Keeping Marsupials’ in the early nineties.)

 

Sad But True

Here is an alarming snippet of trivia!    

A feral cat of a little under four kilos had been shot somewhere in the north of South Australia and its stomach contents examined.    It contained one house mouse, three striped skinks, one lined earless dragon, one smooth earless dragon, three bearded dragons, twenty-four painted dragons and a zebra finch.    So much for our native wildlife.

The really alarming part of this story is that all these carcasses were still easily identifiable, which infers the creatures had probably been caught in the previous twenty-four hours.

 
Bennett's Wallaby
Juvenile NT Brushtail Possum
Swamp Wallaby
Golden Brushtail Possum
Red Kangaroos
Yellow-footed Rock-wallabies
Baby Squirrel Glider
Sugar Glider
Euro

Copyright © The Marsupial Society of Australia Inc. 2003 - 2006 All rights reserved. Privacy Statement

Email Webmaster