Study: Refuge cats fed mostly by humans
September 6, 2017
FLORIDA KEYS — Recently released findings from a 2013 study conducted on public lands in the Florida Keys shows that free-roaming cats eat food mostly from humans. The study, the first of its kind for the Keys, was headed by North Carolina State University researcher Michael Cove.
Collectively, of the 71 unique cats found during a six-month period mostly between Key Largo’s Crocodile Lake National Wildlife Refuge and Big Pine Key’s National Key Deer Refuge, the study found that the majority are consuming a lot of — greater than 80 percent — anthropogenic foods, or food originated from human activity.
Cove said while some may find that number somewhat surprising, he warns about jumping to any quick conclusions.
“There are a couple of caveats with that specific data,” he said.
First, the number doesn’t absolve cats in the death of local wildlife. Cats often kill prey simply as a trophy and never actually consume them. A still from a camera placed at Crocodile Lake shows a cat with what rangers believe is an endangered Key Largo woodrat in its mouth.
Second, Cove and his team of researchers were only allowed to capture cats within the boundaries of public lands. They also set cameras and traps at Dagny Johnson Key Largo Hammock Botanical State Park. He said many cats reside just outside the boundaries, and tend to travel back and forth.
Cove also said that feral cats that have adapted to a diet of almost exclusively wildlife would be harder to catch than stray house cats.
Cosequently, Crocodile Lake manager Jeremy Dixon isn’t ready to slow down the fight to protect the woodrat and other native species in the area anytime soon.
“Diets can change over months with these cats,” Dixon told the Free Press. “And these free-roaming cats [that aren’t feral] can become more predatory in just a short time.”
Aside from the federally-protected woodrat, the Lower Keys marsh rabbit could fall prey to free-roaming cats in the Big Pine area.
Cove wrote in the study that despite a small proportion of the cat population consuming wildlife, previous studies in other areas outside the Keys suggest that just a few individual predators can exert strong effects on threatened species occurring on islands.
Eight unique cats in Key Largo during Cove’s study were determined to be effective predators of wildlife. One dead cat, hit by a vehicle, was found to have inside his stomach the remains of a corn snake, Cuban tree frog and grasshopper.
“The true feral cats that are mostly predatory are definitely the most detrimental,” Cove said.
In Big Pine, only two of the cats studied had diets that consisted of more than 50 percent of wildlife.
Cats that were captured as part of the study had a small patch of fur shaved off one hind leg. The sample was then used to help determine its diet. But even that can be flawed, Cove said.
If an animal being consumed by the cat had a regular diet of mostly human food than it would cause the results to be skewed toward an anthropogenic source.
Determining density of the cat populations on both sections of the two islands was also part of the study. The refuge on Big Pine was found to have roughly five cats per square mile. In Key Largo, that number was much smaller. It was roughly one cat per square mile.
Cove said these numbers correspond with the layout of each study area. On Big Pine, the public land is surrounded by mostly residential establishments. In north Key Largo, along County Road 905, it’s much more rural.
To view the complete study, visit researchgate.net/profile/michael_cove.