|
|
Feral Cats (Felis Catis) and Their Role As An Introduced Species Introduction Here in Hawai’i there is great concern about the state of our native ecosystem. Many news reports have been done about many of the invasive species that have been allowed to proliferate on our islands. Most of these animals, such as the Coqui frog and Jackson’s Chameleon are “exotic” species that many people recognize as a nuisance. Yet, there is one invasive species that is so familiar to us, we may not even realize the possible threat that it may have on our native ecosystem, as well as the native ecosystems around the world. This animal is none other than the feral cat. Feral cats are offspring of domestic cats born in the wild that are wary of human contact. They are organized individuals that live in family packs; some have even compared them with Lions. This paper discusses the concern surrounding feral cats, the methods of controlling them, examples of feral cat eradication on an island, the problems that can arise after complete eradication, the difficulty in eradicating feral cats on a large land mass, and the ethical controversy on how to control feral cats humanely. Why the Concern? Feral cats are excellent predators and have an excellent ability to survive in all types of climates. Feral cat habitats include rainforests, deserts, and alpine areas (Calver et al. 1998). They can survive with relatively no drinking water, and feed on a wide variety of smaller vertebrate animals such as birds, rodents, small reptiles, and amphibians (Calver et al. 1998). Feral cats make homes out of vacant animal burrows, trees, dense brush, caves, and various vacant areas in urban settings such as dumps, alleyways, shipyards, and abandoned cars (Calver et al. 1998). Feral cats breed in the spring through late summer, and a single female can produce up to seven kittens. The cats reach sexual maturity at about one year, and can reproduce continuously until late in their lives (Calver et al. 1998). The major concern about feral cats on islands is that they usually have no natural predators, causing uncontrollable population growth, and severe predation. Even with predators such as the fox, wolf, dingoes, and other large carnivores on larger land masses, the cats have an uncanny ability to maintain stable population numbers. They pose a major threat to native birds as well as small native mammals. It is estimated that feral cats kill an estimated 13 birds per cat per year. There are even human health concerns associated with zoonotic diseases such as rabies, toxoplasmosis, and cat scratch fever (Patronek et al. 1998). Methods of Controlling Feral Cats There are many methods of controlling feral cat populations, but actual results are variable because of the difficulty in locating many of the cat colonies, and also because of the sheer numbers of cat populations. It is estimated that in the mainland United States alone there are at least 30 million feral cats (Pimental 2000).
|
