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Feral cat

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A feral cat

Feral cats are descended from domestic cats but are born and live without human contact. Any environment that sustains people can sustain feral cats, who are known to have thrived in urban, suburban, and rural areas in all parts of the civilized world. They are not to be confused with wild cats or with stray cats (alley cats). Wild cats are descendants of wild species. Stray cats are homeless descendants of domestic cats, but unlike feral cats, have had prior contact with humans and therefore exhibit temperament similar to that of a domestic cat.[1]

Feral cats may live alone but are usually found in large groups called feral colonies. These colonies tend to meet two essential criteria: a good hiding place (often a small wooded area, or abandoned buildings or cars) and a food source. This is why they are often seen near restaurant dumpsters. In urban locales with high-rise housing project tenements, such as much of Eastern Europe, feral colonies typically inhabit any residential building basement with exits suitable to cats (ventilation holes, anti-flooding drains, sufficiently large cracks, loose bricks, etc.), especially when the building itself is public property and lacks an owner who would wish to address the issue.. The average life span of a feral cat that survives beyond kittenhood is about two years for individual cats and five years for cats in a managed colony.[2] An indoor domestic housecat lives an average of 12 to 18 years, though not uncommonly, indoor-only cats have been known to live to their early 20's [citation needed] (12-14 in UK 16+ in USA but stats are incomplete).

Cats are extremely adaptable, and feral felines have been found in conditions of extreme cold and heat.

The environmental impact of feral and free-ranging cats is a subject of debate. Part of this stems from humane concern for the cats, and part stems from concerns about cat predation on endangered species. The domestic cat was distributed throughout the world by human travelers and is not native to many parts of the world. The amount of ecological damage done by cats depends on local conditions, with the most severe effect occurring to island ecologies. Environmental concerns may be minimal in places such as the UK where cats are an established species and few to none of the local prey species are endangered. In Australia, New Zealand and parts of North America they are considered pests due to their threat to endangered species.

History

During the Age of Discovery, ships released rabbits onto islands to provide a future food source for other travelers. They eventually multiplied out of control and cats were introduced to keep their numbers, and that of mice and rats, down. The cats tended to favor local species as they were ecologically naive and easier to hunt. Their numbers too increased dramatically and soon they colonised many areas and were seen as pests too.

Historical records date the arrival of feral cats in Australia at around 1824.[3] Despite that, it has been suggested that feral cats have been present in Australia since before European settlement, and may have arrived with Dutch shipwrecks in the 17th century, or even before that, arriving from present-day Indonesia with Macassan fisherman and trepangers who frequented Australia's shores.[4]

Diet

Feral cats in Australia prey on a variety of wildlife. In arid and semi-arid environments, they eat mostly introduced European rabbits and house mice; in forests and urbanised areas, they eat mostly native marsupial prey (based on 22 studies summarised in Dickman 1996). In arid environments where rabbits do not occur, native rodents are taken. Birds form a smaller part of the diet, mostly in forests and urbanised areas, reptiles also form just a small part of the diet.

Predators

While feral cats may be apex predators in some local ecosystems, in others, they are preyed on by feral dogs, coyotes, wolves, bears, cougars, bobcats, foxes, fishers, feral pigs, crocodilians, snakes, and birds of prey.

Effects on wildlife

Feral cats can be effective hunters of small animals

The impact of domestic cats on wildlife is a century old debate. In a 1916 report for the Massachusetts State Board of Agriculture titled The Domestic Cat: Bird Killer, Mouser and Destroyer of Wildlife, noted ornithologist Edward Howe Forbush stated in the preface:

Questions regarding the value or inutility of the domestic cat, and problems connected with limiting its more or less unwelcome outdoor activities, are causing much dissension. The discussion has reached an acute stage. Medical men, game protectors and bird lovers call on legislators to enact restrictive laws. Then ardent cat lovers rouse themselves for combat. In the excitement of partisanship many loose and ill-considered statements are made.[5]

The report referred to Extinct Birds, published in 1905 by zoologist Walter Rothschild, who stated that "man and his satellites, cats, rats, dogs, and pigs are the worst and in fact the only important agents of destruction of the native avifaunas wherever they go."[6] Rothschild gave several examples of cats causing the extermination of some bird species on islands.

Mainland Australia

Numerous Australian environmentalists and Rhiannon Mortimer claims that the feral cat has been an ecological disaster in Australia, inhabiting most ecosystems except dense rainforest, and being implicated in the extinction of several marsupial and placental mammal species.[7] But scientific evidence supporting this view has been hard to come by, and some researchers disagree with it (Abbot 2002). There is little sound evidence that feral cats significantly affect native wildlife throughout the mainland (Jones 1989; Wilson et al. 1992).[4] Difficulties in separating the effects of cats from that of foxes (also introduced) and environmental effects have hindered research into this. Cats have co-existed with all mammal species in Tasmania for nearly 200 years.[3] The Western Shield program in Western Australia, involving broad-scale poisoning of foxes, has resulted in rapid recoveries of many species of native mammals in spite of the presence of feral cats throughout the baited area.[3] However in 2005 a study was published which for the first time found proof of feral cats causing declines in native mammals.[8] an experiment conducted in Heirisson Prong compared small mammal populations in areas cleared of both foxes and cats, of foxes only, and a control plot. Researchers found that mammal populations were lower in areas cleared of foxes only and in the control plots.

Cats may also play a further role in Australia's human altered ecosystems; with foxes they may be controlling introduced rabbits, particularly in arid areas, which themselves cause ecological damage.[7] Cats are not believed to have been a factor in the extinction of the only mainland bird species to be lost since European settlement, the Paradise Parrot. However they played a significant role in the loss of rare species on Baybbie Britt islands.

Australian folklore holds that some feral cats in Australia have grown so large as to cause inexperienced observers to claim sightings of other species such as puma etc. This folklore is being shown to be more fact than fiction, with the recent shooting of an enormous feline,[9] in the Gippsland area of Victoria. Subsequent DNA test showed the feline to be Felis silvestris catus.[10] Subsequent news of large feral cat sightings appear almost monthly in Australia, and the evidence is very good to suggest a breeding population of these enormous felines in the south-eastern states Victoria and New South Wales.[11]

North America

Cats are effective at controlling small-animal populations, which is one of the major justifications for the keeping of farm cats. Conservationists argue that feral cats contribute to the killing of songbirds and endangered birds, with estimates that bird loss is at 100 million a year because of predation. [12]

Islands and restoration

The Stephens Island Wren went extinct within two years of the introduction of cats to Stephens Island

Many islands host ecologically naive animal species; that is, animals that do not have predator responses for dealing with predators such as cats.[13] Feral cats introduced to such islands have had a devastating impact on these islands' biodiversity. They have been implicated in the extinction of several species and local extinctions, such as the huitas from the Caribbean, the Guadalupe Storm-petrel from Pacific Mexico, the Stephens Island Wren; in a statistical study they were a significant cause for the extinction of 40% of the species studied.[14] Moors and Atkinson wrote, in 1984, "No other alien predator has had such a universally damaging effect."

Feral cats continue to devastate island ecosystems. A ranger at a Hawaiian Island Wildlife Sanctuary witnessed a single feral cat kill 33 ground-nesting sea birds in a single incident. He also noted that cats killed 45 chicks of 75 in one bird colony.[15]

Because of the damage cats cause, many conservationists working in the field of island restoration have worked to remove feral cats. (Island restoration involves the removal of introduced species and reintroducing native species). As of 2004, 48 islands have had their feral cat populations removed, including New Zealand's network of offshore island bird reserves,[16] and Australia's Macquarie Island. Larger projects have also been undertaken, including their complete removal from Ascension Island. The cats, introduced in the 19th century, caused a collapse in populations of nesting seabirds. The project to remove them from the island began in 2002, and the island was cleared of cats by 2004. Since then, seven species of seabird which had not nested on the island for 100 years have returned.[17]

In some cases, the removal of cats had unintended consequences, such as on Macquarie Island where the removal of cats caused an explosion in the number of rabbits and rats which also harmed native seabirds.[18][19] The removal of the rats and rabbits was scheduled for 2007 and it could take up to seven years.[20]

Feral cats, along with rabbits, some sea birds and sheep, form the entire large animal population of the remote Kerguelen Islands in the southern Indian Ocean.

Hybridization with wild felids

Feral cats have interbred with wildcats to various extent throughout the world, the first reported case occurring more than 200 years ago. The significance of hybridization is disputed and hinges on whether the domestic cat is classified as conspecific with the Wildcat or a separate species.[21](see Genetic pollution) In some locations, high levels of hybridization has led to difficulties in distinguishing a "true" wildcat from feral domestic and domestic hybrid cats, which can complicate conservation efforts.[22] Some researchers argue that "pure" wildcats do not exist anymore but this is disputed by others.[21] One study in Scotland suggests that while "true" Scottish wildcats are unlikely to exist, the current wildcat population is distinct enough from domestic cats to be worth protecting.[23]

Zoonotic risk

There is concern about the role of feral cat colonies, wild dogs, and other native mammals, as a vector of diseases, particularly toxoplasmosis, giardiasis (esp. from beavers), rabies(e.g. racoons), campylobacter, Parvovirus and other diseases and parasites that can infect both humans and animals. Felids such as cougars and cats, the mammals they feed on, and undercooked meat and chicken are a source of Toxoplasma gondii which causes toxoplasmosis [24]

Colonies

Feral cat

A feral cat colony is a population (or "clowder"). The term is used primarily when a noticeable population of feral cats live together in a specific location and utilize a common food source—such as food scavenged from refuse bins, dumpsters or supplementary feeding by humans—and reach a population density which might be regarded to be undesirable. However, some who work with feral cats will refer to a smaller population of cats (even as few as a single cat) as a colony if the cats are regularly present at a specific location, especially if they receive care by a human. The term is not typically applied to solitary cats passing through an area. Established feral colonies are located worldwide.

Feral colonies occur when unsterilized domesticated cats are abandoned or "set free" from their human owners, or in some cases, are lost, though cats are very territorial, so not likely to be easily lost. Unneutered males, however, can wander long distances to follow the scent of a female. These cats, though domestic, revert to a defensive temperament the longer they stay away from human contact. Their offspring, being born without any prior contact, are feral. Each subsequent litter, of both the original domesticated cats, and of their offspring (who are likely to breed before their first birthday) will be more feral. They quickly have to learn to fend for themselves. Feral cat population expansion can be quite rapid. If there is no human intervention to stop the colony from growing, there will be some natural, though undesirable, control.

Unneutered males in a colony fight each other for turf and for females. Some will be driven out to find another place to live. Others are wounded and die from the infected wounds. Still others eventually contract FIV (feline immunodeficiency virus) or feline leukemia due to the constant transmission of blood and bodily fluids via fighting and sexual activity.

Though some people may think these cats are "fine" on their own, those who've been trapped in many warm areas where fleas exist are usually found to have a large number of fleas, causing them to be anemic. Both the fleas, and the food source, if limited to garbage and rodents, cause the cats to have intestinal bacteria (such as coccidia or giardia) and parasites (commonly known as roundworms, tapeworms, and hookworms), which lead to diarrhea and subsequent dehydration. They also can often have other health problems such as ear mites, ringworm, and upper respiratory infections.

While all of these illnesses are quite treatable, there must be humans to intervene in order to stop these illnesses from becoming fatal. Due to the number of health problems to which they're subjected, and their fragile immune systems, kittens of the females in the colony sometimes do not survive. Also, unneutered and unsocialized male cats have sometimes been known to kill kittens. [Animal Emergency clinic of Roswell,Ga,US]

The multiple, managed, feral colonies at the Colosseum in Rome exceed 250 cats, and have achieved considerable notoriety. Historians believe the Romans' affection for cats dates from the Roman Empire's conquest of Egypt, where royalty kept cats. Others believe that Rome was spared from outbreaks of the bubonic plague by the city's feral cat population, which kept Rome's rat population low, thus reducing a key plague carrying vector. Other notable colonies include the Canadian Parliamentary Cats, and the cats of Jerusalem [25]

Although cats are traditionally believed to be loners, even despising the company of other cats, these colonies can actually increase the chances of survival with multiple cats to look after kittens. In addition, most cats who've been sterilized seem to enjoy the company of others, especially those born as domestic.

Complaints

A cat touching a car

When a feral colony grows to a large size, those living or working nearby might consider the presence of a locally concentrated cat population to be a nuisance. Complaints made include:

Control and management

See also: Animal population control

There is debate about how to deal with feral cat populations. Some advocate culling feral cat populations by trapping and euthanasia. Others argue that hunting is the most cost-effective method of population control. Opponents to culling argue that if the factors that allowed the colony population to grow in the first place are not addressed as well, a new clowder can form in the same location when cats that escaped trapping and those moving in from surrounding areas continue to breed. This is referred to as the "vacuum effect".[14] Additionally, colonies continue to form anywhere that someone moves away and leaves their unspayed or unneutered cat or cats behind. This is a common problem at rental houses and apt. complexes. The problem is often worse at apt. complexes and large clusters of housing because, when cats are abandoned there, it's less obvious to other residents and to management that they are now homeless. Because human owners of cats are not currently held accountable for sterilizing their pets to prevent them from reproducing, and are not punished for abandoning their pets or for "putting them out" to fend for themselves, this problem continues. Programs designed to kill the cats will not address the lack of human accountability for the problem.

Herd of Feral Cats

Proponents of Trap-Neuter-Return (TNR) programs argue that such programs are more effective and humane. Volunteers trap feral cats, sterilize them through neutering, then release them, though some do keep kittens or cats who are less feral. Variations of the program include testing and inoculation against rabies and other viruses and sometimes long-lasting flea treatments. Tame individuals might be adopted out as pets. Volunteers often continue to feed and give care to the returned cats throughout their lives. There is growing number of people who have domesticated adult feral cats successfully, and even adopted them out to other people. Some feral cat organizations offer techniques to do this.[26][27]

In Australia, control programs are difficult to devise because of the nocturnal and solitary nature of cats, broad distribution in the landscape and continuous additions to the population from abandoned domestic cats. Because of the danger posed to humans handling the animal, captured feral cats are almost always killed. Trap-neuter-return programs are only now being introduced in some urban and suburban areas such as Adelaide. More recently, such programs have been introduced in Sydney by the "World League for Protection of Animals".

On islands, which the vacuum effect does not apply, eradication methods include hunting, trapping, poison baiting and biological controls. For example on Marion Island cats were infected with the feline panleukopenia virus, which drastically reduced their population within six years. The remaining cats were killed by shooting.

Feral cats can also be controlled by larger native predators like coyotes or dingoes because cats are too small to defend themselves against larger predators.

The TNR method is criticized by some groups, who say that there is no evidence that it succeeds in preventing the growth of cat populations, and in fact artificially maintains the numbers of feral cats in many areas.[28] While various long term studies have shown that TNR is effective in stopping the breeding of cats in the wild and reducing the population over time,[29][30][31] opponents of TNR frequently cite a study by Castillo (2003)[32] as evidence that TNR does not work.[33]

Free-ranging domestic cats (well-fed pets who are allowed the freedom to rove around at will by their owners) will frequently continue to hunt and kill small birds and other wildlife if given the opportunity by their owners, often leaving unwelcome 'presents' of freshly killed game for the people in their lives.[34] Unlike wild predators, feral cats in managed colonies are not affected by food pressures, and usually exist in population densities far higher than is the case with animals that will starve or fall prey to diseases if their numbers outstrip the available supply of prey. Wildlife rehabilitation centers are constantly receiving wild animals that have been attacked by cats, and few of these injured animals survive, even if the cat fails to kill them outright.[35]

See also

References

  1. ^ What is the difference between a stray cat and a feral cat? Humane Society of the United States
  2. ^ "ASPCA FAQ: What Is the Average Lifespan of a Feral Cat?".
  3. ^ a b c Abbot, I. (2002) "Origin and spread of the cat, Felis catus, on mainland Australia, with a discussion of the magnitude of its early impact on native fauna" Wildlife Research 29(1): 51-74 abstract
  4. ^ a b Dickman, C. (1996) "Overview of the Impact of Feral Cats on Australian Fauna" Australian Nature Conservation Agency ISBN 0-642-21379-8
  5. ^ Forbush, Edward Howe (1916). The Domestic Cat: Bird Killer, Mouser and Destroyer of Wildlife.
  6. ^ Rothschild, Walter (1905). Extinct Birds.
  7. ^ a b Robley, A., Reddiex, B., Arthur T., Pech R., and Forsyth, D., (2004). "Interactions between feral cats, foxes, native carnivores, and rabbits in Australia". Arthur Rylah Institute for Environmental Research, Department of Sustainability and Environment, Melbourne.
  8. ^ Risbey, Danielle A. ; Calver, Michael C. ; Short, Jeff ; Bradley J. Stuart and Ian W. Wright (2005). The impact of cats and foxes on the small vertebrate fauna of Heirisson Prong, Western Australia. II. A field experiment Wildlife Research 27(3): 223-235
  9. ^ "Engel Gippsland big cat". Retrieved 2008-05-02.
  10. ^ "Feral Mega Cats"
  11. ^ The Big Cat Files
  12. ^ Mott, Maryann (2004-09-07). "U.S. Faces Growing Feral Cat Problem". National Geographic News. Retrieved 2009-08-15.
  13. ^ * Moors, P.J.; Atkinson, I.A.E. (1984). "Predation on seabirds by introduced animals, and factors affecting its severity.". In Status and Conservation of the World's Seabirds. Cambridge: ICBP. ISBN 0-946888-03-5.
  14. ^ a b Barcott, Bruce Kill the Cat That Kills the Bird? New York Times. December 2, 2007
  15. ^ feral cats provoke pity in the city ... and eradication in bird land
  16. ^ Nogales, Manuel et al. (2004). "A review of feral cat eradication on islands". Conservation Biology. 18 (2): 310-319.
  17. ^ Stamps celebrate seabird return. Birdlife.org. July 27, 2005.
  18. ^ The Sydney Morning Herald - Up against rats, rabbits and costs
  19. ^ ABC News online - Fears for sub-antarctic island plagued by rabbits
  20. ^ Parks and Wildlife Service, Tasmania - Plan for the Eradication of Rabbits and Rodents on Macquarie Island
  21. ^ a b European wildcat species account IUCN Species Survival Commission. Cat Specialist Group
  22. ^ European wildcat (Felis silvestris grampia) Arkive.org
  23. ^ Genetic diversity and introgression in the Scottish wildcat. Molecular Ecology (2001) 10: 319–336.
  24. ^ [1]
  25. ^ Hamilton, Jill (2007-07-30). "Blair and the stray cats of Jerusalem". JPost.com. Retrieved 2009-08-25.
  26. ^ Taming Feral Cats and Kittens. Forgotten Felines
  27. ^ Taming feral cats
  28. ^ http://www.abcbirds.org/cats/states/florida_managed.htm [dead link]
  29. ^ Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population
  30. ^ Implementation of a Feral Cat Management Program on a University Campus
  31. ^ Neutering of feral cats as an alternative to eradication programs.
  32. ^ Trap/Neuter/Release Methods Ineffective in Controlling Domestic Cat "Colonies" on Public Lands
  33. ^ New Page 2
  34. ^ Introduction
  35. ^ Cats and Wildlife — Audubon Society of Portland

Further reading

  • Tabor, Roger, Arrow Books (1983). The Wild Life of the Domestic Cat. ISBN 0-09-931210-7
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