Ice those Cuban treefrogs, literally

Extension Service: Ice those Cuban treefrogs, literally

By DOUG CALDWELL, Daily News correspondent

Thursday, July 19, 2007

You may have wondered what that squawky, creaky shoe noise was outside your window at night. Or what was causing all of the unsightly fecal deposits and droppings at the top of your window casements. Most likely it is a foreign invader, the Cuban treefrog (Osteopilus septentrionalis). This large species has dispersed throughout southern Florida during the mid-1970s.

Often they turn up in toilets. Look before you sit!

Today, we’re offering some specific information on the Cuban treefrog and how to eliminate it via excerpts from the University of Florida’s Institute of Food and Agricultural Sciences (IFAS) publications by Steve A. Johnson:

Cuban treefrogs can grow to more than 6 inches in length. Usually creamy white to light brown, they have large eyes and rough skin.

Their skin is coated with a secretion that irritates mucus membranes, so you should not touch the animals with your bare hands.

Cuban treefrogs also cause problems for utility companies and their customers.

Because the frogs like dark tight spaces, they crawl into the transformer boxes and power switches inside power poles to look for food and shelter. The frogs’ bodies are large enough to connect surfaces inside the electrical equipment.

When at least one surface contains an electrical charge, the connection creates a short-circuit, which can cause blackouts and damage equipment. Frog-induced short-circuits have been a problem since the mid-1990s and now cause two or three blackouts per week during the spring and fall for one Central Florida utility company. A single incident can cost up to $10,000 in repairs.

Due to the destructive effects Cuban treefrogs have on native species of amphibians and reptiles, many biologists recommend that Cuban treefrogs be euthanized/killed. That’s harsh, but true. This invader is eating the food sources our native species eat or just plain eating their smaller cousins such as the squirrel and green treefrogs! We recommend a humane method of euthanasia for amphibians. Just make SURE the frog you have is a Cuban treefrog before euthanizing it.

Purchase a small tube of benzocaine ointment, which is used in humans as a pain-killer for toothaches.

There are several well-advertised brands as well as much less expensive store brands (generic brands). One approach might be to capture the treefrogs while they sleep during the day up in the soffit areas of your roof. Some people seem squeamish about this. One might try using a plastic bag a net or maybe a "pooper scooper" or some tool to bag the invader. Once they’re caught, simply take a strip of ointment about 1 inch long (perhaps more for larger frogs) and spread it down the midline of the neck and back of each frog. In 5-10 minutes the animal will be groggy; in 15-20 minutes it should be unconscious, and in about 30-40 minutes it will be close to dead or dead.

At this point, put the frog in a plastic container and freeze it for 3 days. Why? Because we want to ensure that the frog dies — we don’t want a heavily drugged frog to be buried and later wake up 2 feet underground. That would not be humane.

After 3 days, dispose of the carcass by burying it deep enough so that a pet or wild animal will not dig it up, or place it in a plastic bag and put it in the trash.

Freezing is a humane way to kill amphibians because their bodies go into a state of torpor (metabolism slows way down) — just as they do in cold weather outside. If the cold weather is short in duration, the frogs will come out of their torpor state. However, after an extended time in freezing temperatures, the frogs die.

Be sure to wash your hands after handling any frog or toad. They all secrete a slimy film to protect their skin, but the secretions of some species, like the Cuban treefrog, can irritate the skin and eyes of some people.

Another way to capture Cuban treefrogs in order to eliminate them from your property is to attract the frogs to hiding places where they can be easily captured and removed. To do this, simply place short sections of PVC pipe in the ground around your home and garden. This technique is described in detail at:

http://edis.ifas.ufl.edu/UW259

You also can call visit your local extension office if you would like to receive a print copy of the pamphlet.

Frog sing-along

For more info and live frog songs, first go to this Florida Wildlife Extension Web site:

http://www.wec.ufl.edu/extension

Click the link to "Wildlife Information" then find the link to the "Frogs & Toads of Florida" page. This Web site contains images of all of Florida’s frogs as well as recordings of the calls of most species, including the Cuban treefrog.

There are also links to many other useful wildlife related resources at Steve Johnson’s Web site:

http://ufwildlife.ifas.ufl.edu

Click the Extension link then follow the link for "Frogs and Toads." Here you will find many digital images of Cuban treefrogs and native treefrogs to aid with identification of these species.

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Doug Caldwell, Ph.D., is the commercial landscape horticulture extension agent and landscape entomologist with the University of Florida Collier County Extension Service. E-mail dougbug@ufl.edu ; phone 353-4244 extl. 203. Web site: http://collier.ifas.ufl.edu