Cats as an Environmental Problem

Free-Roaming Felines: More Deadly than Windows

Cats are a common pet and garner an exceptional amount of love simply by looking cute. While domestic cats may be loving within the home, they pose a significant risk to small mammals and bird populations when given free access to the outdoors. In Canada, cats are considered to be one of the top sources of direct mortality for birds while also affecting small mammal populations. The same problem can be noted in other countries like the United States, New Zealand, and Australia where cats are considered to be a major anthropogenic source of mortality in wild birds and mammals.

To date, cats have been the cause of 63 species extinctions with 33 species of birds being part of that statistic.

Many are quick to suggest that domestic cats do not contribute to the problem of declining wildlife populations as much as feral cats, but these claims do not take into account how feral cat populations are impacted by domestic cats. Feral cats are the result of human neglect in the form of abandonment or a lack of sterilizing. Studies have found that free roaming females will produce their first litter before reaching 1 year of age and will continue to bear litters in the years to follow. Furthermore, if a cat owner is unable to afford the cost of sterilization for one cat, they are more likely to abandon new kittens or cause further problems if the kittens are also freely roaming while remaining unsterilized. Feral cat populations only continue to increase as people often oppose stricter cat control programs, likely due to the view of cats as a companion.

The Findings of a Wildlife Centre

A wildlife hospital in the US did a study on the effects of free-roaming domestic cats on bird and small mammal morbidity and mortality rates. With 1.4-3.7 billion birds and 6.9-20.7 billion mammals being killed annually by cats, researchers estimated that free-roaming cats contributed to 69% of bird predation and 89% of mammal predation. The wildlife hospital found birds that had interacted with cats had an 80.8% mortality rate while small mammals had a 70.8% mortality rate.

Animals that are injured by a cat and don’t make it to the hospital have an even lower chance of survival as cat teeth are designed to puncture skin, making it easy for bacteria found in the cat’s mouth to be transferred into the hunted animal. An injured animal may succumb to infection within three days of the interaction or enters a weakened state that increases their likelihood of becoming another animal's prey.

What is the Solution?

While several solutions have been suggested, none have worked well enough to curb the threat cats pose to the environment. The use of special collars that hinder a cat's ability to hunt or alert wildlife of their presence are deemed largely ineffective, and many veterinarians in BC have noted this ineffectiveness. Programs that are designed to catch and release feral cats after neutering cannot keep up with the increasing population sizes while most people are averse to the idea of killing off excess cats through lethal injections. Cat owners are also largely unaware of the problems posed by free-roaming cats or believe that the benefits of allowing their cat outdoor time outweigh the damage done to local wildlife populations.

Though there appears to be no perfect solution, pushing for greater awareness of the problem and its causes is a good first step. Recently researchers have urged governments to take further action in informing citizens and place a greater importance on the proper sterilization of domestic cats. In a survey conducted between 389 veterinarians in BC, 79% recommended against unsupervised outdoor access for cats because of disease and safety issues for the cat. This suggests a need for greater collaboration between conservationists and veterinarians so that the safety of wildlife can also become a pressing factor. For cat-owners who wish to give their cat a taste of the outdoors, the creation of catios, enclosed outdoor areas where cats can lounge and climb, and cat walking have become great alternatives.