Conservancy's python trackers find Collier County's largest breeding group

The roaming sentinel, a male python named Argo, with a surgically implanted tracking device, needed just three days to lead researchers to the largest trove of pythons found yet in Collier County.

It was a landmark discovery, just before Valentine’s Day, in the recently completed breeding season. Argo had just found a 100-pound female python getting ready to lay eggs in a culvert. The female snake was captured, and Argo was let loose again to be tracked.

Three days later and a half-mile away, a team with the Conservancy of Southwest Florida found the invasive snake. This time he was surrounded.

“We locate him and then there is another male and another male and another,”said Conservancy wildlife biologist Ian Bartoszek. “We know what all the males are there for, so it’s like, where’s the female?”

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The researchers beat through the brush and started pulling up the tall grass until they found her, a massive egg-laying female that would weigh in at 115 pounds.

Including Argo, she was with seven male Burmese pythons. The eight snakes, called a breeding aggregation, were the most found in one place in Southwest Florida and the western Everglades, where the pythons have been spreading steadily for years.

It matched the largest aggregation found in the known hotbeds of the central and eastern Everglades, where the invasive predatory species has decimated entire populations of small mammals, scientists say.

It’s hard to say what an aggregate of that size means for the density and the number of pythons that now have a foothold in the swamps and thickets of eastern Collier County, Bartoszek said.

Just a few miles away, another male python the Conservancy tracks went the entire breeding season without finding a single female, he said.

When the Conservancy and Bartoszek euthanized the seven pythons and laid them on a table back at the lab (Argo was released again), it was clear to the biologist, who has been chasing the snakes over the last five years, just what the Everglades ecosystem is up against.

“You look at some 250 pounds of python and you just think, what did it take to make that?” Bartoszek said. “How much native wildlife did it take to produce those?”

Part of what makes pythons so hard to track is they leave virtually no trace of their prey. The animals are swallowed whole, leaving no carcass to find, and very little of the prey is excreted. The only way to know what pythons are eating is to catch and dissect them, and to watch what species are dwindling in the wild.

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It's clear from necropsies that pythons, which are thought to have been introduced to southern Florida through the exotic pet trade, are among the top predators in the Everglades. From their stomachs, biologists have pulled bobcat claws, deer hooves, birds, rabbits, opossums and raccoons.

The Conservancy estimated 61 percent of the diet of pythons found in Collier County are small mammals such as rabbits, opossums and raccoons. An additional 29 percent are rodents and birds.

“But if you go to the east coast, you’ll see those percentages flipped,” Bartoszek said. “There they’re eating almost all birds and rodents, because the rest are gone. You’d be very hard-pressed to find a rabbit now in the east.”

Different agencies are taking different approaches to removing the python, but it seems increasingly clear to all involved that it is likely the snakes never will be eradicated. They’re too hard to find and too good at hunting.

The goal now is to slow or stop the spread of the snakes farther north and west. No one is certain they will have success.

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The Conservancy uses radio transmitters to hunt pythons. The trackers have been surgically implanted in about 20 male snakes called sentinels that are then followed to breeding females.

The Conservancy removed about 2,000 pounds of pythons this year, and the same amount last year.

“It’s about removal, but it’s also about research,” Bartoszek said. “As the technology advances, we want to be able to follow the science. To really have an effective control, we have to learn what we can learn about them and their habits to make informed decisions.”

Other agencies are trying programs with pheromone traps, hunting dogs and drones. The most successful, in terms of the number of pythons removed, has been the South Florida Water Management District’s hunting program.

The district has hired 25 python hunters over the past year in Broward, Miami-Dade and Collier counties. Since March 2017, those hunters have removed 922 invasive pythons, said Mike Kirkland, head of the program and a biologist who focuses on invasive species for the district.

“Altogether they were more than 6,600 feet and weighed over 15,000 pounds,” Kirkland said. “We estimate they ate over 150,000 animals; that’s what it would take to get to those numbers.”

The snakes are too numerous and too  difficult to find for scientists to have much hope of eradicating them, Kirkland said.

“But we may be able to achieve containment in some areas,” he said. “It’s really going to take an integrated approach. Trying a number of different methods is going to be our best chance of controlling numbers.”