Cuban tree frog: Invasive species takes over resident’s yard

WINTER HAVEN – Over the past year, Barb Stall has noticed an increase in the frog population at her home on Lake Jessie. But they are not the frogs she usually sees, these guys are whitish in color and something of a pest.

“These frogs have really become an issue over the past year,” said Stall. “I have never noticed them before. The worst problem is when they stick to my windows and create a mess. They have also been killing all of our other frogs. We used to have toads and tree frogs and I haven’t seen any.”

The frogs even get inside her house. “I’ve brought flower pots inside my home and I’ve found them hiding inside. I’ve seen them in my barbecue grill as well and inside my sliding glass door.”

The creature Stall found all over her property is known as the Cuban tree frog and it is wreaking havoc to Florida’s ecosystem and the native frog species.

As the name suggests, the amphibian is native to Cuba but is also found in the West Indies, according to Kristen Sommers, who leads the Florida Wildlife Commission’s impact management section. The Cuban tree frog is listed as an invasive species, which is a species of animal or plant that is introduced by people outside its native range and has the ability to cause damage ecologically, economically and perhaps to human life, Steven Johnson, an associate professor at the University of Florida said. Johnson also is a researcher at the university’s Department of Wildlife Ecology and Conservation.

“Here in Florida, the Cuban tree frog is known to eat native tree frogs, which is the ecological damage,” said Johnson. “They can also cause short circuits in homes by getting into A/C units. These frogs also have a skin secretion that can send people to the hospital.”

The Cuban tree frog is the largest tree frog species located in North America. It was introduced to Florida via cargo shipping crates originating in the Caribbean, Johnson said. The species was first recorded in the Florida Keys during the 1920s and in Miami in 1952.

By the mid-1970s, the Cuban tree frog had reached most areas in South Florida and by 2013 they have established breeding areas as far north as Cedar Key on the Gulf Coast and Jacksonville on the Atlantic Coast, Johnson said.

Colder temperatures in January 2010 killed many of the Cuban tree frogs, but according to Johnson the population numbers have since rebounded throughout Florida with expansion into isolated spots located in the Panhandle.

“Cuban tree frogs have easily spread throughout peninsular Florida by ‘hitchhiking’ on shipments, vehicles and boats,” said Florida Wildlife Commission spokeswoman Lisa Thompson. “They have been successful in expanding their breeding population and they prey upon native Florida tree frogs.”

Native tree frog species being affected by the Cuban tree frog include the Green tree frog, Barking tree frog, Pinewoods tree frog and Squirrel frog.

“Cuban tree frogs are an arboreal species, meaning they spend most of their lives in trees, but occasionally are found on the ground,” said Sommers of the Wildlife Commission. “They have much larger toepads and wartier skin than the native Florida tree frogs and can range in color from tan, gray and brown to olive green and white.”

When it comes to size this species can be found ranging anywhere from 11/2 inches to 5 inches in length, according to Johnson. They have large “bug” eyes.

The Cuban tree frogs prefer forested, wetland areas, Johnson said. “You won’t see them in open, dry areas. They can live just about anywhere. They have become the most dominant tree frog in suburban areas. They prefer structured areas that are moist and damp. Small bodies of water are ideal for breeding such as pools and rain barrels.”

The frogs, which are nocturnal, also can be found in large numbers living in human-altered habitats such as nurseries, gardens, citrus groves and manmade structures, according to Sommers.

Stall said the frogs can be elusive while hiding in tight and dark places. She came back home one day from vacation only to find one in her home.

“They were stuck in one of my flower pots,” said Stall. “I brought my orchids in before we went on vacation. I took it out when we had just gotten back from vacation. It was in our home for two weeks.”

Once an egg mass is produced it may only take three to four weeks for the tadpoles to mature into small frogs according to Johnson. The speed of this growth process depends on water temperature in which the eggs were produced.

The Cuban tree frog has a varied diet, which includes snails, insects, small lizards, native tree frogs, and other frog species according to the Florida Wildlife Commission.

The long-term consequences of this rapid growth in Cuban tree frog population could mean a reduction in available resources for native species, officials said.

“Cuban tree frogs may have a negative impact on Florida’s native tree frogs by competing with them for food and habitat and also by eating smaller species of tree frogs,” said Thompson.

When it comes to reducing their numbers, there is not too much anyone can do, Johnson said.

“One female can lay up to one thousand eggs,” Johnson said. “There is not much we can do at this point from a broad perspective. They hide very well and this particular frog is very difficult to deal with. Once a non-native species is introduced and spreads it becomes difficult to catch and reduce the numbers. There is no hope of eradicating their numbers.”

Johnson recommends that because of the frog’s destructive nature it should be captured and humanely euthanized.

Johnson recommends applying a 1-inch strip of benzocaine ointment along the back of the frog. Once the ointment has been applied, place the frog in a plastic grocery bag for 15-20 minutes or until it is unconscious. Then place the frog in the freezer overnight to ensure death and dispose of in the trash the next day.

Education is playing a big role in helping residents understand the Cuban tree frog and the best ways to remove these animals from around their homes and communities.

“Just because we will not eradicate the entire population doesn’t mean we should give up on educating people on how it spreads and how to reduce their numbers,” said Johnson.

Sommers said the Wildlife Commission provides educational information on how to deal with these frogs and how to properly remove them from homes.

Stall said when she realized what she was seeing near her home were Cuban tree frogs she couldn’t believe it.

“I noticed them because I was like ‘oh my God, I read that article in the newspaper’ and I went ‘that is what we have, no wonder we haven’t seen other frogs.’ They are terrible and gross.”