Contact: Brian Clark, University of Maryland Extension | bpclark@umd.edu
ANNAPOLIS, MD (April 15, 2010) – Feral cats (Felis catus) are a perfect invasive species. They are non native to North America, have a high reproductive rate, relatively low mortality, and high dispersion rates. They also have the ability to be cute and cuddly, a perfect shield from those that wish to do them harm.
Cats are the purrfect hunter, a mix of power, stealth, and speed. Domesticated cats are simply scaled down versions of their larger cousins. As a domesticated species, they have put their hunting capabilities to good use, protecting our health and property from rodents that would destroy what we have. However, when these cats are released into the environment on a permanent basis, they can disrupt the balance of an already fragile ecosystem. When cats are first released into the environment, they are generally referred to as strays and can be reincorporated into domestication with little difficulty. As the generational gap increases between domesticated and non-domesticated, adult feral cats are less likely to be redomesticated.
However, small cats are not part of the native food web in North America and can wreak havoc on an ecosystem. It is believed that between 50 and 100 million feral cats roam the United States, with 70 million being a conservative consensus among experts. Small mammals such as mice and moles make up a majority of their prey. Even with their ability to fly, birds, especially nestlings or fledglings, make up approximately 20% of a feral cat’s prey. During a study of feral cats in Wisconsin, a single cat averaged 3.1 animal kills each day. If each cat kills one animal, each day, up to 36.5 billion animals could be killed by feral cats each year. Feral cats can take a toll on native wildlife, decimating populations already under stress due to habitat shrinkage. Their hunting abilities are used on rodents, birds, insects, reptiles, amphibians, and even fish. The number and size of prey that a small cat can bring down will amaze you. Even full grown rabbits can be killed. Supplemental feeding of feral cats is not an answer. Even well-fed feral cats will capture and kill, but not always eat, their prey.
Many of the feral cat’s other nuisance habits can be attributed to mating behaviors. These behaviors include noise from fighting and mating, and the smell from their pheromone-laced urine. When they come into contact with roaming domesticated cats, there is also the chance for the spread of diseases like rabies and parasites, such as fleas.
For those who love all animals, this presents a huge problem. Do you control the feral cat or not? Failure to control a highly predatory, non-native species that has proven to kill many of the small native species we enjoy is a necessity to preserve the overall balance of an ecosystem. But to kill a cat, an animal that so many people love, is a political nightmare for farmers and environmentalists.
Control can be a tricky issue. The first step is to prevent the release of new cats into the environment. If you are unable to care for your cat, adoption is preferred. An animal shelter is the next best and often legally the only other option. The next step is dealing with existing populations of feral cats. Many people are protective of feral cat colonies. There are hundreds of organizations out there that offer education to the public and protection to the cats. The two most common control measures are trap-euthanize or trap-neuter-return (TNR). Euthanizing feral cats is used primarily by government institutions as it provides control with the lowest cost. TNR is the procedure most recommended by feral cat advocates.
Then there is the cycle of life. Feral cats themselves are hunted. Large hawks and owls will fly off with the smaller individuals. Coyotes will often kill cats which compete for their food resources. The reemergence of coyotes into Maryland should prove interesting to examine over time.
Love your pet. Take care of the native environment. Spay or neuter. Keep your cats indoors.
For more information about this and other Invasive Species of Concern, visit www.mdinvasives.org
photos available electronically on request.