Environment

Pythons stake out new territory: the Florida Keys

For the first time, wildlife officials have found Burmese pythons breeding in the Florida Keys, bad news for disappearing Key Largo woodrats, cotton mice and other small mammals consumed by the voracious snake.

On Thursday, the Florida Fish and Wildlife Conservation Commission reported that three hatchlings were found over three weeks in August in North Key Largo. They are the first hatchlings documented in the area, suggesting the exotic snakes invading marshes on the mainland have now staked out new territory where the last known population of docile woodrats build their intricate nests in woody hammocks.

“While we have documented Burmese pythons in the Keys for a while now, this is the first time we have documentation of hatchlings,” FWC section leader Kristen Sommers said in a statement. “This is not surprising considering the proximity to the known breeding populations in the Everglades.”

Pythons first began appearing in the Everglades in the 1980s, likely freed by unhappy pet owners. By 2000, they were fast becoming the state’s most notorious invasive species.

The snakes have been blamed for driving down the population of raccoons, rabbits and other small mammals in Everglades National Park. Last year, a study concluded they had taken over as the top predator in the region. The South Asian snakes are also adept at altering habits to live in their swampy new home, capable of swimming and inhabiting more diverse environments, according to a five-year study completed by the U.S. Geological Survey last year.

The Keys have had sightings before — 31 were reported in the last five years — but never hatchlings. While no nests or eggs were found last month, the hatchlings are almost surely the offspring of wild pythons, which might have swam to the island, said USGS biologist Bryan Falk.

“There’s been observations of them swimming in Florida Bay in open water and they obviously arrived [in Key Largo] by swimming,” he said. “They may have been breeding [before] but we didn’t make any observation.”

A state environmental worker spotted the first 18-inch snake in North Key Largo on Aug. 2, Sommers said. A second, about the same size, was spotted the next day in the same location. On Aug. 23, a third snake was found. Only one of the snakes was captured alive, making it impossible to conduct genetic tests to determine whether the snakes came from the same clutch, Falk said.

The snake will be sent to the Florida Museum of Natural History in Gainesville, where it will be housed and cataloged as the first official documented Key Largo python, Falk said. Sommers said all three snakes were found near the Crocodile Lake National Wildlife Refuge, although officials are not disclosing exact locations for privacy reasons.

If the snakes are breeding in North Key Largo, the chubby reddish-brown woodrats that inhabit the refuge could be in more dire trouble. Woodrats were added to the endangered species list in 1984 when just about 6,500 remained. By 2010, when the state launched a failed attempt at introducing captive bred rats, the number was down to about 300. In a not-surprising twist of fate, a woodrat led biologists to the first documented python: a team following a radio-collared rat instead found the python, digesting their target.

The spread of the snakes also raises concerns over other endangered species including the Lower Keys marsh rabbit and the petite Key deer on Big Pine. Both rabbits and deer regularly turn up on python menus.

In an effort to keep Key Largo from becoming a snake pit, wildlife officials said Tuesday they would begin sending postcards with information about pythons to residents, asking for help tracking them down. Anyone who spots a python should take a picture and report it to the state hotline at 888-Ive-Got1 or online at www.IveGot1.org. Over the winter, when snakes are easier to find sunning themselves, the team will plot out a new strategy to tackle the invasion, Sommers said.

“The challenge will be the same as it has been for the last 10 years. Even if we remove all the pythons from the Keys, the likelihood that more are going to get there is really high, so consistent surveying is really important,” she said. “And for the public to be our eyes on the ground is really important because they can help direct our efforts.”

Follow Jenny Staletovich on Twitter @jenstaletovich

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