Trap–neuter–return
The process involves live-trapping the cats, having them neutered, ear-tipped for identification, and, if possible, vaccinated, then releasing them back into the outdoors.
Cats suffering from severe medical problems such as terminal, contagious, or untreatable illnesses or injuries are often euthanized.
[4] In the past, the main goal of most TNR programs was the reduction or eventual elimination of free-roaming cat populations.
[9][10][11][12][3] Literature reviews have found that when studies documented TNR colonies that declined in population, those declines were being driven primarily by substantial percentages of colony cats being permanently removed by a combination of rehoming and euthanasia on an ongoing basis, as well as by an unusually high rate of death and disappearance.
Variant acronyms and terms include: TNSR (for 'trap–neuter/spay–return'),[16] TNVR ('trap–neuter–vaccinate–return'),[17] TNRM ('trap–neuter–release–maintain/manage') where 'maintain' generally means caregivers feed and monitor the feral cats after they are returned to their territories,[18] and TTVAR ('trap–test–vaccinate–alter–release').
Unlike traditional spays (ovariohysterectomy) and neuters (castration), which are done in TNR, the vasectomies and hysterectomies in TVHR result in sterile but sexually active cats.
[22] RTF ('return to field') or TNS ('trap, neuter, shelter return') are alternative approaches that simply focus on the trap and desex portion and do not include a colony management aspect.
Abandonment may also have occurred if owners believed that cats would be better off under the care of the program rather than surrendered to a shelter where they would face the risk of euthanasia.
[13] The success of specific focused studies to advocate TNR as a solution for controlling and reducing free-roaming cat populations worldwide is problematic.
More broad-based approaches include using matrix population models to estimate the efficacy of euthanasia versus trap-neuter-return for management of free-roaming cats, such as the one researchers established for use in urban environments.
Abandonment may also have occurred if owners believed that cats would be better off under the care of the program rather than surrendered to a shelter where they would face the risk of euthanasia."
[4] Managed TNR programs that involve continuous active intervention on detection along with treatment and prevention of some of the more common diseases and parasites may help improve their overall health.
Having un-spayed female cats in an area will attract un-neutered males with the attendant problems of spraying, fighting and caterwauling.
There are methods to help mitigate the environmental impact imposed by feral cats through different forms of population management.
[65] In Australia, hunting by feral cats helped to drive at least 20 native mammals to extinction,[66] and continues to threaten at least 124 more.
[67] A 2013 systematic review in Nature Communications of data from 17 studies found that feral and domestic cats are estimated to kill billions of birds in the United States every year.
[68] Numerous studies have shown that free-roaming cats can have a significant negative impact on native wildlife through their predation.
They cause considerable wildlife destruction and ecosystem disruption, including the deaths of hundreds of millions of birds, small mammals, reptiles, amphibians, and fish.
[72] According to a PLoS One paper published in 2019, evidence of species recovery has been observed post-eradication of feral cats and rats from islands.
Contaminated soil is an important source of infection for humans, herbivores, rodents, and birds and several studies suggest that pet feces contribute to bacterial loading of streams and coastal waters.
Beyond pragmatic and scientific considerations, cultural heritage, ethical beliefs, and social and economic impacts play critical roles in efforts to address it.
[88] In 2021, the Parliament of Australia issued a report that rejected TNR as an effective means of controlling feral cat populations; however, Australian animal welfare groups generally support it.
[95] TNR was practiced in Denmark in the mid-1970s, as reported at the 1980 Universities Federation for Animal Welfare (UFAW) symposium in London.
The goal was to facilitate specific areas for feeding to help the populations of stray cats and to improve their welfare.
It suggested that TNR efforts without an effective education of people to control the reproduction of house cats (as a prevention for abandonment) are a waste of money, time and energy.
[108][self-published source][109][failed verification] The earliest documented practice of trap–neuter–return was in the 1950s, led by animal activist Ruth Plant in the UK.
In the mid-1960s, former model Celia Hammond gained publicity for her TNR work "at a time when euthanasia of feral cats was considered the only option".
Hammond "fought many battles with local authorities, hospitals, environmental health departments" but stated that she succeeded over the years in showing that control "could be achieved by neutering and not killing".
[citation needed] The first scientific conference on "the ecology and control of feral cats" was held in London in 1980 and its proceedings published by the Universities Federation for Animal Welfare (UFAW).
[111] In a federal case, American Bird Conservancy v. Harvey (2014), conservationists sued Rose Harvey, the Commissioner of New York State Parks, under the Endangered Species Act for failing to prohibit activities supporting feral cats in a state park where the Piping Plover, a threatened species, was known to nest.
