Household cats prey on wildlife everywhere and finding ways to combat this tendency occupies scientists and wildlife conservationists. Societies for protection of animals oppose culling cats or imposing restrictions on their mobility and feeding for the sake of protecting wildlife.
Last month, the renowned British nature filmmaker David Attenborough claimed that cats play a major role in the decimation of several bird species in Britain.
Attenborough recommended that cat owners attach a bell to their cat’s neck to warn wild animals of their approach. This issue is also perturbing intellectuals such as the American novelist Jonathan Franzen. In a blog posted on the Washington Post in which writers were asked to choose a graph representing the year 2013, Franzen selected one showing causes of bird mortality in the United States due to human activity, in which household cats figured prominently.
Risk of extinction
The Israel Nature and Parks Authority held a professional conference last week, in which Prof. Yoram Yom-Tov of Tel Aviv University addressed the impact of roaming cats and dogs on wildlife. He noted that in Israel, they prey on several protected species that are at risk of extinction, such as the forest dormouse and the greater Egyptian gerbil. Like many other scientists across the world, and concurring with nature conservationists in Israel, Yom-Tov expressly supported the shooting of roaming cats and dogs in nature reserves and open areas. “The place of pets is at home, not in nature,” he said.
Studies in the United States and Canada published last year estimated that in both countries cats kill hundreds of millions of birds each year. According to the Canadian study, published in Avian Conservation and Ecology, cats are the leading cause of bird mortality related to human activity. Societies for protection of animals claim that these studies were based on only a limited number of sites, from which conclusions were extrapolated to the entire country.
Furthermore, there is little evidence regarding the density of cats in each area, so that there is no scientific basis for claiming that cats are predators that endanger entire populations of wildlife. Scientists, however, believe there is sufficient evidence regarding the density of cat populations and enough observations of their predations to allow for projections on a national scale, which show the gravity of the situation. Yom-Tov gave an example of a castrated cat in Metula in northern Israel, which in the course of one year brought its owner 48 wild animals that it had killed.
An examination of comprehensive studies turns up a regional disparity in the rates of predation, with the highest rates occurring in rural areas close to open spaces. According to the Canadian study, urban cats make up half of the national cat population, yet account for only one-sixth of the birds killed.
Without regard to the exact dimensions of the phenomenon of wildlife predation, animal protection organizations stick to their traditional positions, according to which the way to deal with the problem is widespread sterilization and castration. This, they believe, will reduce the pressure on wildlife and improve the health and quality of life for the cats. It will also obviate the need to shoot cats, which is immoral and inefficient in their view.
However, scientists question the effectiveness of sterilization and castration. They note that success rates (in terms of numbers of cats treated in a given urban area where they have a constant supply of food) are not high. These groups are usually joined by cats from adjacent areas that have not been sterilized or castrated. This treatment gives legitimacy to the continued feeding of these cats and these, in turn, continue to hunt wildlife. As an example illustrating the complexity of the issue, scientists described a colony of cats in Key Largo in Florida that operated in a partially fenced area. Although the number of cats was reduced, they continued to kill off a rodent species endemic to the area that was at risk of extinction.
What further complicates matters is the way many cat owners interpret the need to sterilize and castrate their cats, and their ignorance regarding the pets’ breeding. Last month the British periodical Veterinary Record published a survey of 715 cat owners in England, and it turned out that a vast majority believed female cats should be allowed to have one litter before they are sterilized. The researchers believe this alone accounts for 850,000 extra births. Many owners mistook the age at which cats can become pregnant, believing it to be later than it is, thus accounting for the large numbers of unplanned litters.
Alley cat allies
Several organizations for animal protection oppose not only culling, but any form of restriction on feeding and mobility. The American organization Alley Cat Allies opposes any registration of cats or restrictions on their roaming the streets. It claims this will increase the number of cats ending up in shelters where they are put down. In opposition to these groups, scientists trying to preserve wildlife claim cat owners ignore the rights of wildlife. Yom-Tov noted that priority should be given to conservation of wildlife rather than to protection of cats that hunt these animals, since these wild animals are rarer.