Last week staff joined visiting investigator Paul Andreadis (Denison University) on an outing to track invasive Burmese pythons in the reserve. Five pythons caught earlier this year were implanted with radio transmitters and then released at their capture site; an area of the reserve with very limited access.
Walking along the grassy berm where the snakes are known to congregate in the winter, Andreadis raised his hand-held antenna overhead and dialed in the frequency of an adult female python on a portable radio receiver. He was able to find her signal, and the quiet beeping sound grew louder as he got closer to his target. Entering the snake's proximity, some back-and-forth wandering was needed to fine-tune the exact location. Then he set the device down on the ground near the entrance to an abandoned armadillo burrow. "She's here!" he announced, and jotted down the GPS coordinates. He went on to explain that the isolated location, with high ground and pre-existing burrows surrounded by brackish waters, seems to be the perfect combination for this species.
Two of the five tagged snakes, both adult females, have remained faithful to the site. "She's been in this burrow the last few times we checked, so there is a good chance she's getting ready to lay eggs if she hasn't done so already," said Andreadis. The other tagged female was tracked to another burrow a few hundred yards away. "Since mother pythons stay with her eggs, we'll be able to find these clutches and prevent the babies from entering the population," he added.
The other tagged snakes, an immature female and two adult males, have been tracked to locations within a couple miles of the main site. The primary goal of the radio-telemetry project, work that Andreadis is performing under contract from the US Geological Survey, is to determine how far the snakes range over the entire year. "I'm guessing they will return here come winter," he says. Andreadis believes this site is their winter staging area, where they bask in the sun and look for mates, but when temperatures rise, they move out to more favorable hunting grounds.
Starting in January 2012, Andreadis and reserve staff initiated a systematic removal campaign for pythons in partnership with the Southwest Florida CISMA and the research involves other partners including the Conservancy of SW Florida and USGS. The isolated location and limited access to the site have made it easier to document the impact of their efforts. Comparing the numbers from 2013 to 2012, Andreadis calculates a seven-fold reduction in apparent python numbers. "Last year, the average was a little over one snake captured per visit. This year, it's about one snake every six visits. So, our efforts are working, at least on a local scale," he said.
"The features of this site, and the resources and staff at Rookery Bay, make this the perfect location to do this project," he concluded, adding that the things we learn here will help inform the exotic animal control efforts of land managers across Southwest Florida.