Full Title Name:  Detailed Discussion of Feral Cat Population Control

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Anthony E. LaCroix Place of Publication:  Michigan State University College of Law Publish Year:  2006 Primary Citation:  Animal Legal and Historical Center 1 Country of Origin:  United States

Controversy has arisen over how best to deal with populations of feral cats. While cat advocates fight against killing cats, bird advocates and others see them as destructive to protected species. Legal issues of property ownership, causation, and classification of cats are central to the question of human liability for feral cats.

I. Introduction

      Because feral cat colonies are of great concern to communities where they reside, and especially because of their potential to dramatically alter the makeup of ecosystems through predation, the question of who is legally responsible for these animals must be addressed. Loss of wildlife by cat predation is a concern not only to conservationists, environmentalists, and bird lovers, but also to all members of the public who, knowingly or not, depend on the health of their neighborhood ecosystems to sustain their quality of life. More important, however, are the preservation of local species diversity for its own sake and the creation of humane policies toward solving human-caused problems of cat overpopulation. The difficulties which attend problems such as dealing with the volatile population dynamics of cats cannot be avoided by use of cursory and ultimately ineffective methods of control. A thorough and intricate problem necessarily requires a comprehensive and sustainable solution. This paper examines the character of the feral cat problem, the legal ramifications of cat ownership and care, and competing viewpoints on how best to deal with non-domesticated cat populations. An argument is then made for abandonment of any generalized approach and in favor of local policies and ordinances focused on root causes.


A. What is Meant by "Feral?"

      For Felis silvestris catus , the domestic cat, there is a very large group of individuals which holds an uncertain status somewhere between "wild" and "domestic." ( Click here for a brief biological summary). Feral cats have been defined as cats which were once domesticated, but were abandoned, lost, or ran away. Because the environmental variables acting upon the descendants of such cats are essentially identical to those which act upon wild animals, first generation "feral" cats are properly called "stray," and only later generations "feral." The distinction between a wild animal and a feral animal lies in the typically urban habitat of feral animals and the fact that members of the species are traditionally domesticated. Aside from tradition, in areas sparsely occupied by people there is little reason to call a wild-born cat "feral," as opposed to "wild."

      Adult feral cats are nearly impossible to domesticate, while strays are sometimes re-socialized. Feral kittens, however, can be socialized before they reach about twelve weeks old. Feral cats often form colonies, or clowders, in a particular location around a common food source, such as a dumpster, open garbage dump, or where people offer handouts. The colony size is necessarily dependent on the size of the food source. Abandoned or lost domestic cats often join feral colonies out of necessity, the only readily available food source having been claimed by the colony.

      A feral cat lives a much more tumultuous and dangerous existence than a cat in captivity. The life expectancy of a feral cat which survives as a kitten is less than two years, while a house cat usually lives from fourteen to twenty years. The risks of disease, injury from fighting, malnutrition, and traffic all account for the short lives of feral cats. Feral cat colonies should not be confused with managed cat colonies, which are created and closely monitored by humans, as discussed below. For further information on the lives of feral cats, visit http://www.alleycat.org and http://www.abcbirds.org/cats .


B. Feral Cat Colonies

      Feral colonies are a hot topic among cat proponents, bird and other small-species proponents, and some local governments and state agencies. The problems created by feral cats stem largely from their skill as hunters and the fecundity of the species (female cats can have two to three litters per year). A peculiarity of cats is that they continue to hunt even when well-fed. See http://www.abcbirds.org/cats/factsheets/colonies.pdf . For this reason, feral cat colonies have decimated species of wildlife, some of them endangered, in locations with island ecologies, including in Hawaii, the Caribbean, and Pacific Mexico. These particularly dramatic instances of cat predation serve both as examples of the effects of an unchecked feral cat population and as ammunition for bird advocacy groups, who suggest that feral cat populations are far too destructive to be left alone or placed back into the wild after being spayed or neutered. These groups support the eradication of feral cats by kill methods. See http://www.abcbirds.org/cats .

      An additional objection to feral cats concerns their potential to carry and spread disease. While there is disagreement over the extent to which cats spread disease, they are known to transmit ringworm, parasitic worms, feline immunodeficiency virus, and feline leukemia. They also transmit toxoplasmosis, a parasitic disease which is particularly dangerous to pregnant women and babies, and cat scratch fever, which also affects humans. In addition, cats are the companion animal most commonly infected with rabies in the United States. http://www.catchannel.com/cat/vetlibrary/article_5602.aspx . However, cats may be a relatively minor rabies threat to other species because rabies is transmitted through saliva and not scratching. http://www.feralcat.com/sarah3.html . On the whole, the concern over diseased feral cats is largely aesthetic, a large group of diseased cats being more objectionable to people than a large group of healthy cats. In addition, cat and bird advocates both voice concern over the miserable lives of the cats themselves due to disease. See, e.g., http://www.helpinganimals.com/Factsheet/files/FactsheetDisplay.asp?ID=120 . At any rate, the threats of cat scratch fever, and especially toxoplasmosis, to humans are genuine concerns. The question of how best to humanely deal with cat predation, disease, and overpopulation has resulted in controversy.



II. Trap and Kill vs. Trap-Neuter-Return

A. TNR (Trap, Neuter, and Return)

      Trap, Neuter, and Return, or "TNR," became popular in the 1990s as a humane way to control the population of feral cats. With TNR, the cats are typically trapped, spayed or neutered, and vaccinated against rabies and distemper (an often fatal virus). They have their left ears "tipped" (clipped) for identification as a sterile cat, and then are released into a "colony." The colony is usually managed by volunteers who feed and monitor the cats. For further information on how TNR works, see http://www.sfgate.com/cgi-bin/article.cgi?file=/gate/archive/2002/12/09/urbananimal.DTL , about one of the longest-running and largest TNR programs in the country.

      TNR proponents oppose kill methods mainly on two grounds. First, they believe it is inhumane and unethical to destroy cats whose existence is entirely a result of human behavior. Second, proponents point out what has been called the "vacuum effect" which results from removal of cats. When individual cats are removed from their habitats, their food source remains available, yet no longer protected. This inevitably causes cats from surrounding areas to move in and claim the food source, and thus there is no reduction in the number of feral cats in the colony. Conversely, proponents say, in a managed colony altered cats remain to protect their food source, yet they do not reproduce. Therefore, a closely-monitored colony will become smaller over time. See http://www.feralcat.com/sarah2.html . TNR resulted from dissatisfaction with the status quo on cat control, which has traditionally been "trap and kill."


B. Trap and Kill Methods

      The most common method of feral cat population control is "trap and kill," or feral "eradication." Groups that support this seemingly direct, simple, and immediate method of population control have several reasons for doing so. Bird advocates witness the present population of feral cats preying on the existing population of songbirds, and respond accordingly. Where significant numbers of songbirds are endemic, bird advocates point out that TNR does not reduce the impact of cat predation on birds because the cats, no matter how well fed, continue to prey on the birds. They suggest that only elimination of the cats will prevent loss of birds, but that people can prevent the trapping and killing of cats by responsibly looking after and sterilizing their pets.

      The American Bird Conservancy estimates that native birds represent 20-30% of the prey of free-roaming cats. http://www.abcbirds.org/cats/resolution.pdf . The group encourages "eliminat[ion] of free-roaming cat colonies through humane capture by animal care and control facilities." The elimination of cats by animal control agencies typically involves trapping the animals and then killing them by means of carbon monoxide poisoning. This has been criticized as an inhumane and dangerous practice because the cats die a slow, suffocating death and carbon monoxide poses a hazard to animal control personnel. See http://www.gaschambers.freehomepage.com/ .  As a result, animal advocate groups have encouraged use of lethal injection with sodium pentobarbital, which is considered a more humane method of euthanasia.

      Euthanasia is also reluctantly supported by People for the Ethical Treatment of Animals, which cites the miserable lives of feral cats as justification for the practice. http://www.peta.org.uk/factsheet/files/FactsheetDisplay.asp?ID=166 . However, PETA supports managed colonies where they are vigilantly monitored and maintained. http://www.askcarla.com/answers.asp?QuestionandanswerID=241 . According the group, a managed colony is acceptable where the cats are protected from roads and other dangers, vaccinated, and closely-monitored in areas where they do not pose a threat to wildlife. However, PETA believes TNR is rarely a success, and thus supports humane euthanasia as the lesser of two evils— an alternative preferable to the fate awaiting free-roaming cats.

      While "trap and kill" remains controversial, "shoot to kill" has also been suggested. In 2005, the Wisconsin Conservation Congress proposed changing the classification of free-roaming cats to that of an "unprotected species." The proposal, ultimately struck down by voters, would have made any free roaming cat, whether stray or feral, without a collar fair game for hunters. The proposal was designed to protect songbirds and other wildlife. Proponents of the change cited the decline of songbird populations in the United States, and believe that cats are a major cause of that decline. However, there is doubt as to the extent to which cats have caused the decline in songbird numbers. The National Audubon Society reports that human-caused factors, such as habitat destruction, pollution, and collisions with buildings, are the primary causes of songbird decline. For more information on the Wisconsin proposal, see http://animallaw.info/statutes/stuswi2005question62.htm .

      Those who see TNR as a destructive practice have suggested that colony managers might be held liable for predation by their cats. Questions of legal ownership must be answered before it can be determined whether the theory has merit.  



III. Holding Colony Managers Responsible for Predation by Feral Cats

      While the historical relationship between humans and cats is well-established, the legal relationship between the two species is more tenuous. While most municipalities and states have detailed laws concerning the possession, care, and control of dogs, surprisingly few have cat-specific laws (for more on state cat law, see the Detailed Discussion of State Cat Laws ). The question of who is responsible for the actions of a particular cat depends on the actions of people as they relate to the cat, while the movement and behavior of the animal itself may also determine who bears responsibility. The law is often its own worst enemy when it comes to animals, and the law concerning cats is no exception. For example, while the common law insulates cat owners from liability for their cats, endangered species laws usually ignore the question of ownership altogether, instead focusing on the cause and effect relationship of a person's actions as to a protected species. Moreover, local governments create ordinances which may contradict federal and state conservation laws. This creates a precarious situation for feral colony managers, who are considered by some conservationists to be exacerbating the feral cat problem. Before considering the question of whether a cat owner is liable for the behavior of her cat, it must first be determined what constitutes "ownership" of animals in the first place.


A. The Question of Ownership

      Some local governments have expressly defined ownership. For example, The Kern County, California Code of Ordinances defines "owner" as follows:

[A]ny person who owns, possesses, controls, keeps, cares for, harbors or has custody of the animal for fifteen (15) or more consecutive days, except for feral cat caretakers, a veterinarian or an operator of a grooming shop, a kennel or a pet shop engaged in the regular practice of this business as such .

§ 7.04.160.

Interestingly, the definition specifically precludes the possibility that feral colony managers will be considered owners of the cats. It therefore follows that the managers may not be held liable for the destruction of any animals the cats prey upon, because liability often hinges upon ownership. However, ownership may be irrelevant under federal conservation laws, as discussed below. Under this definition, it also seems that feral cats in managed colonies are truly "wild" and not possessed by anyone for legal purposes, and therefore there may be no person responsible for their predation or well-being. Absent a statutory definition such as this, the question of ownership requires exploration of some old principles of the common law.

      The law's inclination toward classification leaves feral cats with an uncertain status. It is settled that a domestic cat is treated under the law simply as a chattel of the owner, as are cattle, sheep, and chickens. (See http://www.animallaw.info/articles/arusgfrancione1996.htm for more on the legal status of companion animals.) Domestic animal owners are generally not liable for the actions of their animals unless it can be shown they possessed knowledge of the animal's propensity to cause damage. See, e.g., Goodwin v. E. B. Nelson Grocery Co ., 239 Mass. 232 (1921). While laws imposing strict liability for harm caused by one's animal exist, they are usually specific to dogs. This seemingly contradictory insulation of domestic animal owners from liability stems from the classification of the species as one which is normally not dangerous. In other words, although the owner of a domestic cat has an absolute property right in the cat, he is absolutely not liable for what the cat does, because cats are not considered dangerous. The exception to this common law rule is embodied in the Restatement of the Law, Second, Torts:

§ 509 Harm Done by Abnormally Dangerous Domestic Animals

(1)  A possessor of a domestic animal that he knows or has reason to know has dangerous propensities abnormal to its class, is subject to liability for harm done by the animal to another, although he has exercised the utmost care to prevent it from doing the harm.

(2)  This liability is limited to harm that results from the abnormally dangerous propensity of which the possessor knows or has reason to know.

Therefore, absent statutory exceptions, domestic cat owners are likely responsible for the destruction of songbirds by their cats only if they are negligent or reckless in failing to control an abnormally harmful cat. Because cats are normally prolific hunters, their predatory behavior does not bring them within the common law exception to the rule. Consequently, owners of stray cats are not liable for songbird destruction under the common law. Clearly the evolution of this rule did not occur with an eye toward the propensity of cats to prey on other species.   

      Like all wild animals, feral cats are born outside of captivity, and are genetically predisposed toward certain survival-oriented behavior. It is likely the practice of domestication, and especially the practice of regular feeding, that fundamentally alters the behavior of a cat so that it is properly given a separate legal classification. The trouble is that the law has often drawn a distinction and classified all members of the species Felis silvestris catus as domestic animals. The consequences of instead recognizing feral cats as wild animals may remove the cloud of doubt over the legal status of feral cats.

      At common law, a wild animal was "owned" by the holder of land on which the animal resided. This constructive possession creates a property interest in animals, known as property ratione soli (property by reason of ownership of the soil). See State v. Mallory , 83 S.W. 955 (Ark. 1904). First-generation feral cats (strays) likely do not constitute property ratione soli because they are normally lost or abandoned by their true owners, and therefore are not wild. However, the offspring of these cats could be considered legally wild, and the owner of land on which feral colonies exist could be considered the owner of the cats. Therefore, in jurisdictions where liability depends upon ownership, the principle of ratione soli could be determinative. Holding land owners responsible when cats on their property prey on protected bird species would encourage responsible cat management and localize the problem to a great extent.


B. Exotic Species

      As suggested above, to draw a distinction between a feral cat and any wild animal is somewhat arbitrary. A further question of classification is whether Felis silvestris catus is an exotic species, and if so, if cats are harmful in an ecological sense. Although technically not native to North America, and therefore "exotic" by definition, the purpose of labeling a species "exotic" is to single it out as one whose introduction disrupts the equilibrium of   an existing ecosystem, either by serving as a significant new predator or by serving as a new source of prey for existing wildlife. An introduced species in either role can have a dramatic, even devastating, effect on the population numbers of native species. There is disagreement as to whether or not Felis silvestris catus should be considered an invasive species, and such treatment has significant consequences under the Lacey Act , which bans the importation of such species. See 16 U.S.C. § 3371 (2006) ; See also 18 U.S.C. § 42 (2006).

      The Department of Interior maintains a list of species which are considered both exotic and invasive. Before a species on the list can be brought into the United States, a permit must be obtained. Domestic cats are not considered to be an invasive species requiring federal protection against their importation. See Shawn Gorman & Julie Levy, A Public Policy Toward the Management of Feral Cats , 2 Pierce L. Rev. 157, 158 (June, 2004). While this may be of little practical consequence, since the problem is with already existing cat populations, it is instructive because the federal government does not officially recognize that cats are a destructive species. Many states also have laws banning the importation of non-indigenous species. These laws either specifically exclude cats from the list or cats fall outside of the scope of the law because of their classification as domestic animals. See id. at 160.


C. Laws Concerning Endangered and Protected Species

      The Endangered Species Act prohibits the "taking" of endangered fish or wildlife in the United States, and can be enforced by any person. 16 U.S.C. § 1538 (2006). The Act is a very powerful tool for conservation groups and has been given a liberal interpretation by courts. It has been suggested that the Act might be used to discourage TNR programs by characterizing the maintenance of a feral colony as a taking when endangered birds are preyed upon. See Pamela Jo Hatley, Feral Cat Colonies in Florida: The Fur and Feathers are Flying , 18 J. Land Use & Envtl. Law 441, 454-57 (Spring 2003). Although the relationship between the acts of the managers and the ultimate destruction of birds is rather attenuated, there is strong precedent from the Ninth Circuit which gives credence to this theory.

      In Palila v. Hawaii Dept. of Land & Natural Resources , the Department had been maintaining a colony of feral sheep and goats within the habitat of the Palila bird, which exists only in Hawaii and had been classified as an endangered species. 639 F.2d 495 (9th Cir. 1981). The feeding habits of the herd and its practice of bedding down near the tree line caused a decrease in the rate of forest regeneration. Because the effected trees were within the officially designated habitat of the critically endangered Palila bird, it was held that the Department's maintenance of the herd was a "taking" under the Act. In fact, the Ninth Circuit affirmed a grant by the district court of summary judgment for the plaintiff. This is a striking conclusion, because it illustrates the tremendously broad definition attributed to the word "take," notwithstanding apparent problems with causation. As the Court noted, the Act defines "take" to mean "to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any such conduct." 16 U.S.C. § 1532(19) (2006) . "Harass" had been defined as "an intentional or negligent act or omission that significantly disrupts normal behavior patterns of the endangered animal." Palila at 497 . The court did not find it necessary to establish that any of the Department's specific acts were negligent or intentional. Rather, it applied what appears to be a strict liability standard to those whose actions, in any manner, lead to the loss of endangered animals. The court also found the Department had "harmed" the birds. Harm "may include significant habitat modification or degradation where it actually kills or injures wildlife by significantly impairing essential behavioral patterns, including breeding, feeding or sheltering." 50 C.F.R. 17.3 (2006).

      If the herding and feeding of feral sheep and goats in a manner which indirectly causes the loss of endangered birds over time is so clearly a "taking," what might be the outcome of a case against a group that traps, feeds, alters, and monitors animals which directly hunt and kill endangered birds? Palila makes it clear that no intent to cause harm to endangered species is needed, nor, seemingly, must it be foreseeable that one's acts will cause loss of the endangered animals. Moreover, as mentioned above, the Endangered Species Act's prohibition on takings is independent of the question of property ownership. Under the circumstances, feral cat colony managers may be placing themselves at odds with federal law.

      The Migratory Bird Treaty Act makes it a crime to take any native migratory bird. As with the Endangered Species Act, there is no element of intent required. Hatley at 452-53 . Given the number of bird species covered by both the ESA and the MBTA, a cat would be hard pressed to avoid hunting a protected species, if it was inclined to try.



IV. Putting the Focus on the Roots of the Problem

      Legal issues aside, it is significant that the two opposing sides of the TNR debate are essentially in agreement over at least two critical issues. First, all concerned agree that the behavior of cat owners toward their pets must be addressed in order to get this problem under control. There would be no feral cats without careless or irresponsible pet owners who either purposely or inadvertently allow their unaltered cats to roam free or "dump" them. The potential for unaltered cats to reproduce in exponential numbers when supplied with a sufficient food source is staggering. See http://keysy.com/forgottenfelines/growth.htm . Under the circumstances, legislation, at least at the local level, pertaining to the licensing, sterilization, and control of pet cats is in order. Many, if not most municipalities have ordinances addressing the responsibility of owners toward dogs. Such ordinances can be used as models for cat laws.

      The second point of agreement is that, except for a few instances of mass predation in places with island ecologies, feral cat colonies exist only where there is a human-supplied food source. While colony managers are well aware that an increase in the number of cats requires an increase in the amount of food that must be provided, it is equally true that an increase in food results in an increase in the number of cats, where the cats are unaltered. Stated otherwise, the population number of feral cats is a function of the amount of food available to them. The basic biological reality that birth rates decrease where food is scarce and increase where it is plentiful should lead us to focus on how humans are feeding free-roaming cats. Such a "root cause" approach is infinitely more productive that a "who do we sue?" approach.

      A critical area of local focus should be the elimination of open containers containing edible garbage. An entire colony of cats might exist in and around a single garbage dumpster behind a shopping mall. The cats are generally not there looking for food; they are there because they have found food and are protecting it; this is what defines a feral cat colony. Several generations of cats within the colony have survived potentially off of this one dumpster. By properly sealing such containers from access by cats, the birth rates within the colony will decrease and the colony will reach a sustainable size. Although policing dumpsters is hardly a priority of most local governments, rethinking waste management policies is critical to feral cat population control.



V. Conclusion

      While the welfare of feral cats depends on the willingness of people to deal with them responsibly and intelligently, the future of an endangered species is dependent on precisely the same thing. Neither of these causes is furthered where well-intentioned groups with conflicting approaches to the problem seek redress in court. This is particularly true of the feral cat control dilemma, because the problem can be effectively addressed by means of concerted local effort, as both "sides" agree. As such, the intelligent and responsible thing for citizens, conservationists, cat lovers, and bird lovers to do is turn their attention to finding workable solutions specific to their localities. Whether or not the law will treat feral cats as wild animals, there is reason to do so in practice. A feral cat is an actor within its ecosystem just as wild squirrels, deer, and birds are. The problem is not the fact that they are cats, but rather that we do not see cats as we see squirrels, deer, and birds—as wild animals. People must confront cat overpopulation both by refusing to created more wild cats in the first place through abandonment, and by preventing the inevitable cat population expansion which occurs where human food is made abundantly available to cats.


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