Some people believe that people who let their domestic cat loose outside in the natural environment to hunt and wander are placing more value on the life and the needs of their cat than on the life of the prey that the cat kills.
It is an argument that is about the relative importance of different species of nonhuman animal. I am fairly certain that most people who let their cat go outside are not thinking about it at that sort of philosophical level.
Non-cat owners do, however, think about these sorts of things because in their eyes the domestic cat precipitates such a belief by coming home after a roam and presenting prey to their owner.
The trouble is, though, that often people like to make sweeping generalisations about domestic cat predation. What is said is not always based upon hard evidence. This is probably because allowing the domestic cat to wonder and hunt outside is an emotional subject which invariably polarises people. Native species of birds are particularly likely to elicit a defence by ornithologists despite the fact that the cat mainly preys on ground dwelling mammals.
Even scientists get it wrong. Because there is little hard evidence about domestic cat predation, scientists sometimes extrapolate from studies which are not reflective of the general cat population and therefore come to incorrect conclusions. Sometimes scientist let their own personal views interfere with their objectivity which can introduce bias to their conclusions.
Other biases can be introduced into studies. For example, owners of cats that are better hunters are more likely to volunteer to participate in studies about domestic cat predation. Relatively few domestic cats bring in very large numbers of prey which skews the results and artificially inflates the mean number of prey. On a scientific basis, the “median” would be a more suitable way of measuring domestic cat predation. What I’m saying is that the scientific processes for averaging predation affects the outcome and I’m drawn to the conclusion that because this topic is so emotive, scientists can perhaps introduce biases.
One example of a study that perhaps presented skewed results and which was well discussed was a one-year study of prey brought home by 70 domestic cats in an English Village in 1987. The study concluded that domestic cats accounted for at least 30% of sparrow deaths in the village and as a consequence they were considered to be the major predator of house sparrows. I presume that that conclusion was then extrapolated to mean that the domestic cat is the major predator of house sparrows across England. However, in the area of the study there was a high density of sparrows. In addition, other predators were not assessed in the study and further there was no indication that this level of predation had caused the sparrow population to decline.
In one case, the media jumped on a study in 1989 proclaiming that “cats kill millions of small mammals and birds every year”. The study, in fact, was a questionnaire involving 1,300 people living in rural Wisconsin, USA. Twenty percent of the 800 people who took part in the study did not have cats. Of the remainder, there was an average of 5 cats per residence or farm. These people reported 279 items of prey being captured by their cats on the 20 to 30 farms/residences in the area of the study. Mammals represented 60% of the prey and birds represented 23%. You can see that the media’s conclusions and headlines were grossly exaggerated. This is not untypical and continues today, 2014.
Even people who have a bias against the domestic cat and favour wildlife over the domestic cat would probably admit that there are certain species of wildlife which could be considered pests requiring control by predation. The domestic cat and semi-domestic cat is very good at controlling rodent populations around barnes or stables and this is generally accepted even by people who dislike cats.
Apparently, in some urban environments there are large populations of some birds and pests which has been attributed to a more favourable climate and better food availability. In three Italian parks there were a higher number of prey items (animals preyed upon) together with a higher number of predators than is found in the countryside.
Also, in the urban environment, the number of predators that prey on bird nests such as blue jays, raccoons and opossums increase due to a proliferation of food supplies. Also, suburban birds may, in fact, be under less pressure from predation by domestic cats then they would be from the range of native predators that no longer live close to human habitation.
I think the point made in the last two paragraphs is this: there are very many influences and factors which affect the outcome of studies on domestic cat predation, which makes it extremely difficult to generalise through extrapolation about the extent of predation and which therefore distorts and skews the pro-cat versus pro-wildlife debate.
The truth of the matter is that it is probably illogical to have a pro-cat versus pro-wildlife debate because both groups are nonhuman animal species with, ultimately, the same rights and, as Ruth (aka Kattaddorra) says, we should have a live and let live policy towards them all.
One of the biases introduced is due to the argument that the domestic cat is a non-native species (introduced species) in countries such as America. Well, the domestic cat has been in America for over 400 years and for about 2000 years in the UK. At what point do you allow an animal to be accepted as part of the ecosystem of a country? Certainly the feral cat in America is now fully integrated into the country’s ecosystem. This should be accepted by people from both sides of the argument and their treatment of the feral cat adjusted accordingly. Also cats are often one of many species introduced to a country (i.e. rats, dogs, mongooses and weasels) although cats are criticised more often. Bias comes to mind yet again.