RefugeUpdate
March/April 2009 Vol 6, No 2

Snakes Alive!

In Florida, an exploding population of pythons is threatening national wildlife refuges in the Florida Keys and north as far as Arthur R. Marshall Loxahatchee Refuge. (USFWS)

by Susan Morse

In south Florida, the genie is out of the bottle – and the U.S. Fish and Wildlife Service knows from experience it’s not going back in. This time, it’s a top-of-the-food-chain predator and a prolific breeder. And it’s not yet clear if the combined efforts of federal and state agencies will be enough to stop its spread.  

The critter is the Burmese python, an Asian snake that can grow to more than 20 feet and nearly 200 pounds. It is showing signs of outgrowing the 400 square miles of Everglades National Park where it has established a breeding population. Estimates now put the number of pythons there at between 20,000 and 30,000. A predator of virtually every Florida creature from white-tailed deer to endangered wood storks and adult alligators, the python is threatening national wildlife refuges to the south in the Florida Keys and north as far as Arthur R. Marshall Loxahatchee Refuge.  

Eliminating the pest is no longer feasible; managing it is the only option. The Refuge System’s invasive species coordinator Michael Lusk strikes a determined tone: “Our role here is to keep [the problem] from spreading further. That’s where we’re showing leadership.”  

While officials consider tactics from legislative actions (two bills are being drafted), to tracking the snakes via radio transmitters (surgically implanted by University of Florida researchers), to developing a biological control (still years away), the National Wildlife Refuge System is taking steps.

In March, Loxahatchee Refuge became the state’s northernmost site to host a Python Patrol class, led by the Miami-Dade Fire Rescue Venom Response Team and senior refuge biologist Cindy Fury. Experts taught staff how to confirm suspected python sightings and capture the animals safely for study – alive, if possible. So far, there have been two unconfirmed sightings at the refuge. Said Loxahatchee project leader Sylvia Pelizza, “It’s just a matter of time.”

Fury proposed the training after attending a similar event, spearheaded by The Nature Conservancy, in January at Crocodile Lake National Wildlife Refuge on Key Largo, 110 miles to the south. At least nine sightings have since been confirmed on the key, separated from the Everglades by six miles of water. By January, the U.S. Geological Survey (USGS) placed 59 python traps in and near Crocodile Lake Refuge, with the refuge’s permission. Unwieldy “Pets”

How did a native Asian reptile become a major U.S. menace? According to the Service, animal traders imported some 100,000 of the colorful snakes between 1996 and 2006, captive bred them and sold them as pets. But some owners were not charmed when, after a year, their 20-inch hatchlings morphed into hungry eight-footers. They released them illegally into the wild.

 A recent report said the Burmese python’s potential for range expansion extended into the entire southern third of the country. (USFWS) A USGS report released in February projected the Burmese python’s potential for range expansion, based on climate comparisons for the United States and their native habitat. The report showed their potential range extending into the entire southern third of the country. One researcher studying the endangered Key Largo woodrat tracked a radio-collared specimen into a python’s stomach. Studies of the contents of python stomachs have found white-tailed deer and adult alligators, along with a host of other animals.

Python Catching 101

How do you catch a python? Carefully. Loxahatchee Refuge biologist Cindy Fury recalls her irst training: “I grabbed the snake by the head, as I was taught,” she says, “and it slammed into me and then wrapped around my legs. I couldn’t move and I could feel it start to squeeze… I said, ‘Whoa.’” Another member of the class unwrapped the snake, “because I couldn’t do it and still hold the head. It was a really good example of what you don’t want to have happen if you’re out by yourself in the field.”

 At the Florida Key Refuge Complex – home of the endangered key deer and Lower Keys marsh rabbit – manager Anne Morkill wants to believe controls can still work. “The Everglades is a goner. Here, we have an opportunity to hold the line.” ◆

http://www.fws.gov/Refuges/refugeUpdate/pdfs/refUp_MarchApril_2009.pdf