Impact of Cat Populations on Native Species

Domesticated cats are ubiquitous in many societies, and this is especially true in the United States. Cats represent a relatively low-maintenance option as a pet, with unique and endearing personalities to match. However, their presence and spread has not gone without a significant impact on the environment and on species they prey upon.

For every cat that enjoys a comfortable lifestyle with humans, the scientific consensus states there is one in the wild or in a free-roaming group. These “feral” cats are problematic in virtually every respect: their own safety and health is obviously suboptimal and they carry, and transmit, diseases with little opportunity for medical intervention. Surprisingly, cats are the leading rabies vector among all domestic animals in the United States.

All cats possess remarkable predatory instincts and are adept killers of rodents and birds, the latter of which is a major concern.

Birds a frequent target for owned and feral cats alike

As of now, the extinction of at least 37 species of birds can be principally linked to hunting by cats. Certainly there are other factors – natural or anthropogenic – but feline predation has been shown as the primary cause. Even non-threatened birds with healthy populations and distributions are feeling the adverse effects of free-roaming and owned cats – the gray catbird, so aptly named for its meow-like call, loses 4 of 5 fledglings (or roughly 80%) in many urban areas. The common culprit? Predation by cats.

According to the University of Florida Conservation Clinic (a January 2003 report to the U.S. Fish and Wildlife Service), approximately 65 percent of owned cats are not kept exclusively indoors. This means that, in addition to the population of wild cats, nearly 100 million cats at any time may be outdoors. To put that into context, as many as 271 million small mammals and 68 million birds will be killed in one year, in just Florida alone.

A 2011 study conducted by a team of Smithsonian scientists states that “Domestic cats in suburban areas that are allowed outside spend the majority of time in their own or adjacent yards, so they are likely able to intensely monitor, locate and hunt inexperienced juvenile birds.” This is not to say that cats are culpable for utilizing their ancient, and proven, instincts; this is even more true for cats required to sustain themselves without human owners.

Trap-neuter-return: solution or injustice?

For free-roaming and feral cats, implementing effective policies – and subsequently monitoring them for legitimate success – is inherently difficult. Management of these unfortunate animals varies across agencies and states. Conservationists grapple with the undesirable option of euthanasia, and argue that we do not permit other animals (such as dogs) to roam free or live in wild colonies – so why do we forsake cats?

The concept of trap-neuter-return, or TNR, is a process to curb the breeding of feral cats: the main objective is to eliminate cat over-population. First, it requires positive and verifiable evidence of a feral cat colony. Once that has been established, qualified animal officials are dispatched to trap and/or sedate the animals. The captured cats are then neutered to prevent further reproduction, and some disease-free and friendly felines warrant consideration for placement in shelters and adoption centers. Understandably – and unfortunately – most are not receptive to intimate human contact and those perceived as dangerous are euthanized. The remainder are returned to the wild, and some may integrate into colonies under unofficial human supervision (such as volunteer caretakers).

Many conservationists, wildlife biologists, and animal welfare proponents oppose TNR. A cat surviving in the wild endures distress beyond comprehension, and such conditions are less humane than euthanasia.

Eradication of feral cats would be a tremendously resource-intensive undertaking and such efforts would face public disapprobation. As with most controversial issues, a sufficiently-informed public would offer new perspectives. Some pet owners, knowing the possibility of euthanasia at shelters, prefer to release the animal into the wild without being cognizant of the true implications and the harm caused to their pet and to nearby wildlife.

Shelter animals at least face the prospect of being re-homed. Once an animal becomes feral, the options are restricted greatly, and quality of life will be inadequate.

No easy answers

Ultimately, there are a myriad of political and social dynamics that have prevented any substantive progress. Citizens overwhelmingly support cats and often overlook the realities of the situation; it is not uncommon for people to favor the subsidizing of feral cat colonies while granting little consideration for native wildlife on the brink of extinction. Those expecting a facile solution will surely be disappointed.

In order to improve the welfare of cats everywhere, it is imperative that pet owners act responsibly and agencies enforce policies in place (such as local ordinances that require owners to keep their domestic animals under control – once again, dogs are prioritized while cats are not accounted for).

Large-scale efforts to alleviate the devastating impact of cats on birds and small animals may not yield immediate results. However, there will be catastrophic consequences if all parties continue to sidestep the problem; human inaction will cause profound long-term suffering for cats, birds, and many other species.

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