The American Bird Conservancy (ABC) supports the removal of feral cats from the environment, advocating for humane euthanasia for those cats that are deemed unadoptable.
"Feral cats are a highly destructive, invasive species that are at least, in part, responsible for the extinction of 33 species," ABC spokesperson Robert Johns told Discovery News.
He added, "Outdoor cats are the number one, human-caused direct source of bird mortality. They kill up to 3.7 billion birds every year."
ABC proposes that there should be incentives for cat owners not to let their pets run wild outdoors. An incentive, for example, could be to fine cat owners for not complying.
Lisnik said that in many municipalities, there are no specific ordinances addressing cats and/or TNR. Bans on feeding outdoor cats have proven to be difficult to enforce, and rarely work, she said, "because caring people will find a way to feed the cats, even with the threat of a fine or worse. Also, the cats were attracted to the area in the first place due to an available food source, such as a dumpster or rodent population, something that a feeding ban does not address."
Is TNR even successful?
Johns said that "we have yet to see a single 'managed' cat colony lead to the elimination of the colony. If TNR worked, we'd be seeing that, and we simply don't."
Julie Levy, director of the Maddie's Shelter Medicine Program at the University of Florida, has conducted many cat population studies that show the impact of TNR on a given feline population. Based on her findings, there is good and bad news.
The good is that, according to her studies, TNR can reduce cat populations in a humane manner so long as at least 75 percent of a feral cat colony is sterilized. The bad is that the process can be slow, with some colonies persisting for 10-15 years before eventually ending.
"For people who do not want the cats around, this can be difficult to live with, even if nuisance behaviors diminish," Lisnik said. "In cases like these, we recommend that local trap/neuter/return groups work to help these individuals, considering humane deterrents, such as a car cover, fencing, motion activated lights or sounds, etc., to keep cats out of gardens or off cars or patios."