Domestic cats may well be a perfect pet to some people; however, a recent study has discovered how destructive cats can be to ecosystems. Cats have already played a major role in the extinction of at least 33 different animals.
The recent study was published using U.S. figures, it is estimated that there are as many as 84 million cats living in America, and if each of these cats is killing an estimated 23 to 46 birds per year this results in up to 3.7 billion birds killed due to cats alone.
This makes cats more dangerous to birds than any man-made invention including cars, poison and buildings. Unfortunately cats aren’t just a problem for birds, they are also killing as many as 20 billion small mammals a year as well.
The issue arises as cats are essentially an invasive species, with no natural predators, and hugely popular amongst pet owners.
The study did emphasise that un-owned cats are by far the largest culprit in these numbers. One easy solution is to keep domestic cats inside to prevent them harming local ecosystems; however, one environmentalist in New Zealand has gone a step further.
Gareth Morgan has set up a website called “Cats to Go,” which is encouraging owners to make the cat they own their last. His hope is that people will gradually phase out the cat population in New Zealand, and in turn hopes that this will increase the native bird numbers.
There is a flip side to this argument however, that by reducing cat numbers we indirectly increase the population of rats and other rodents. Rodents such as weasels and rats are well known for climbing trees to find and eat bird eggs; it could well be the case that cats are actually causing an increase in bird numbers by keeping more damaging predators in check.
As with most food chains, it is not as simple as remove A and B increases, yet some islands have managed to make the bird population flourish. One such example is Kapiti Island, located 5km west of New Zealand’s North Island. The island has managed to remove all of the island’s bird predators such as rodents and cats, thus increasing the bird population significantly.
Although not all of the facts are clear, one thing is: it is down to human involvement that cats are having this level of impact. If people stopped allowing domestic cats to fend for themselves, these figures would be significantly reduced.