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Trap-Neuter-Return (TNR), also known as Trap-Test-Vaccinate-Alter-Release (TTVAR), is a method being promoted as a humane alternative to euthanasia for managing and reducing feral cat and dog populations. TNR relies on sterilization of the cats or dogs so that they don't breed. The method has been gaining increasingly widespread acceptance in the United States since the late 1980s and early 1990s, to the point that some municipalities have embraced the method and support it through veterinary subsidy programs. More recently in Eastern Europe schemes have been set up to control street dog&cat populations.
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TNR methodology
Trap-Neuter-Return begins with the trapping of feral cats using humane cage traps. The captured feral cats are taken (in the trap) to a veterinary clinic where they are sterilized by the castration of males and spaying of females. Typical TNR programs also involve providing the cats vaccinations against certain diseases like rabies, feline panleukopenia, herpes, and calicivirus. Finally the cats are marked so that they can be easily identified as a sterilized feral, usually by cropping the pointed end of the ear so that it has a square appearance (known as ear tipping) or cutting a notch at the tip or on the side of the ear.
In some programs the cat might also be tested for feline leukemia virus (FeLV) and/or feline immunodeficiency virus (FIV) prior to sterilization, and possibly euthanized if the test is positive. The value of FIV/FeLV testing is the subject of debate among feral cat advocates, with some stating that doing testing is an ineffective use of limited funds that otherwise could be used to sterilize more cats, and others holding the position that it is unethical (and inhumane) to release a cat that is carrying a virus that causes deadly disease and that is transmissible to other cats.
After the cat is sterilized and vaccinated, it is placed back in the trap and allowed to recover from surgery. It is subsequently released to the site of capture.
Rationale given for use
Practitioners of TNR believe that this method is, over the long-term, a more effective population reduction approach than traditional (e.g., eradication) methods. They argue that when all cats in a feral cat colony are removed, fertile cats from surrounding areas typically move into the vacated area to take over shelter and food resources -- and begin breeding. On the other hand, sterilized feral cats returned to their site of capture do not breed, and practitioners claim they keep fertile outsiders away. The population in a managed colony is said to be reduced by attrition over time as kittens and tamable adult cats are removed to adoptive homes, seriously ill or injured cats are euthanized, and other cats die due to natural and accidental causes. Any new cats that arrive in a managed and regularly observed colony may be identified and sterilized before they breed.
Effectiveness
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Please help improve this article by expanding it. Further information might be found on the talk page. (March 2008) |
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,[1][2][3] opponents of TNR frequently cite a study by Castillo(2003)[4] as evidence that TNR does not work.[5]
Longcore et al (2009)[6] have extensively reviewed and evaluated available scientific literature on TNR and have found that scientific literature contradicts six major claims that advocates of the practice make.
This comprehensive review shows that TNR programs are not effective at reducing populations of feral cats. Mathematical modelling shows that 71 – 94 % of a population must be desexed for the population to decline assuming there is no immigration. Long term studies have shown that populations do not decrease and in several cases, populations have increased due to increased dumping of cats. TNR programs that have resulted in decreased populations have also included intensive efforts to adopt a large proportion of the population.
The authors detail how cat populations are not stable and movement of cats is significant between urban areas and nearby woodland. Cats do not defend territory if there is ample food and populations can reach high densities when there is a reliable food source.
Effect on wildlife
The Trap-Neuter-Return approach is controversial. Feral cats, which are considered an introduced species in some parts of the world, predate upon wildlife. Many wildlife and bird advocacy organizations argue that TNR does nothing to address this issue or the possibility that predation by feral cats could threaten endangered species. TNR groups disagree, saying that although sterilization does not affect the ability of cats to hunt, TNR programs reduce total predatory impact by reducing the size of the colony. They go on to dispute the significance of predation by feral cats, stating that the cats are scapegoats blamed for the effect of habitat destruction caused by irresponsible human development. This disagreement is manifest in the public debates that occur when a feral cat colony is located near or in an environmentally sensitive area such as a coastal wetland.
In 2009 the Audubon Society of Portland announced a team-up with the Feral Cat Coalition of Oregon in an effort to curb feline overpopulation in area. [7]
Longcore et al (2009) in their extensive literature review found that feral cats harm wildlife on continents as well as islands and recorded instances of bird extinction from feral cats on islands and harm to wildlife on continents. Fragmented ecosystems near urban areas are similar to islands and more susceptible to feral cat damage. Feral cats in urban areas also pose significant risk to migratory birds.
The authors establish that feral cats are exotic and do not fill an existing niche and that even well-fed cats significantly impact on wildlife.
The article details population and comparative studies of the adverse effects of feral and free roaming cats on birds and other wildlife. In particular, ground-foraging species and native rodents are particularly impacted.
Feral cats act as vectors for diseases that can impact on domestic cats, wildlife and humans, examples include feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), fleas, ear mites, hookworms, roundworms, Bartonella, Ricksettia, Coxiella and Toxoplasma gondii. Fecal matter from feral and free-roaming cats has also shown to degrade water quality.
The authors conclude by urging greater engagement from conservation scientists to communicate that management of feral cats is not just an animal welfare issue and to provide further credible scientific information to policy makers about the adverse ecological consequences of condoning the indefinite maintenance of feral cat colonies through adoption of TNR as a preferred management scheme.
See also
References
- ^ Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population
- ^ Implementation of a Feral Cat Management Program on a University Campus
- ^ Neutering of feral cats as an alternative to eradication programs.
- ^ Trap/Neuter/Release Methods Ineffective in Controlling Domestic Cat "Colonies" on Public Lands
- ^ New Page 2
- ^ http://cwhrbird.org/documents/Longcore2009.pdf Critical assessment of claims regarding management of feral cats by Trap- Neuter - Return by Travis Longcore, Catherine Rich and Lauren M Sullivan
- ^ Portland Audubon and Feral Cat Coalition Team Up
External links
Pro-TNR:
- Alley Cat Rescue, Alley Cat Rescue
- Humane Society University, online course on TNR
- "What is Trap-Neuter-Return", SpayDay page.
- Alley Cat Allies, a feral cat advocacy organization
- Neighborhood Cats, a New York City organization working on promoting TNR nationwide
- Feline Resistance, an organization formed to confront TNR opponents
- The Humane Society of the United States, celebrating animals/confronting cruelty
- Göteborgs katthjälp, Introduced TNR in Sweden
- TNR-metoden.se, Swedish site about TNR
- Djurhemmet Tigerharen, Swedish animal shelter promoting TNR
- ca-r-ma.org, Canadian organization fostering TNR via a system of community based affiliated groups throughout the Maritime Provinces
- TNR dogs: A template for change, an easy to understand guide on how to set up a TNR scheme in your municipality
- Forgotten Cats, TNR organization
Anti-TNR:
- Policy statement on feral cats from The Wildlife Society, opposing the use of TNR
- Cats Indoors! campaign from the American Bird Conservancy, opposing the use of TNR
- TNR Reality Check: Site that contests TNR applications
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