Invasive Burmese pythons are taking a toll on Florida’s native birds

Great blue heron.

The Everglades National Park in Florida is home to hundreds of species of native wildlife. It has also become the well-established home of the non-native Burmese python—known to be a predator of native species. Now scientists, for the first time, have conducted a detailed analysis of the avian component of the python’s diet and the negative impact the snakes may have on Florida’s native birds, including some endangered species.

The Burmese python (Python molurus bivittatus), native to Southeast Asia, was first recorded in the Everglades in 1979—thought to be escaped or discarded pets. Their numbers have since grown, with an estimated breeding population in Florida in the tens of thousands. As researchers investigate the impact of this snake in the Everglades, scientists from the Smithsonian Institution, South Florida Natural Resources Center and the University of Florida examined the snake’s predation of the area’s birds. They found that birds, including endangered species, accounted for 25 percent of the python’s diet in the Everglades.

A Burmese python eats a great blue heron in Florida.

“These invasive Burmese pythons are particularly hazardous to native bird populations in North America because the birds didn’t evolve with this large reptile as a predator,” said Carla Dove, ornithologist at the Smithsonian’s Feather Identification Lab in the National Museum of Natural History. “Conversely, the python is able to thrive here partly because it has no natural predator to keep its numbers in check.”

The remains of an American coot recovered from the intestinal tract of a Burmese python captured in Florida.

The scientists collected 343 Burmese pythons in Everglades National Park as part of their study between 2003 and 2008. Eighty-five of these snakes had bird remains in their intestinal tract. From these remains the team identified 25 species of birds by comparing feathers and bone fragments with specimens in the Smithsonian’s collection. The results reflected a wide variety of species, from the 5-inch-long house wren to the 4-foot-long great blue heron. Four of the species identified (snowy egret, little blue heron, white ibis and limpkin) are listed as “species of special concern” by the Florida Fish and Wildlife Conservation Commission. The team also identified the remains of a wood stork, which is a federally endangered species.

Researchers implant a radio transmitter in a 16-foot, 155-pound female Burmese python (Python molurus) at the South Florida Research Center, Everglades National Park. Radio-tracking builds understanding of where pythons spend their time and therefore where they can be controlled in practice. Photo courtesy of Lori Oberhofer, National Park Service. (Credit: U.S. Geological Survey)

Researchers implant a radio transmitter in a 16-foot, 155-pound female Burmese python (Python molurus) at the South Florida Research Center, Everglades National Park. Radio-tracking builds understanding of where pythons spend their time and therefore where they can be controlled in practice. Photo courtesy of Lori Oberhofer, National Park Service. (Credit: U.S. Geological Survey)

“These pythons can also inhabit a wide variety of habitats, so their impact is not restricted to just the native species within the Everglades,” Dove said. “The python’s high reproductive rate, longevity, ability to consume large prey and consumption of bird species are causes for serious conservation and control measures.”

The team’s findings are published in the scientific journal BioOne, March 2011.

–Johnny Gibbons

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  • Philip Townes

    More python-poop from government “scientists.” Smithsonian ornithologist Dove doesn’t know what she is talking about; if she did she wouldn’t say python have no natural predators. Pythons are eaten by alligators, birds including but not limited to herons, egrets and hawks, as well as raccoons,king snakes and other carnivores.
    Pythons are also cold-intolerant: recent winters have drastically reduced python populations, pretty well keeping them in check. 7 of 9 telemetry study subjects didn’t make it through one winter. http://www.usark.org/uploads/PythonColdTempfulltext.pdf
    http://www.usark.org/uploads/Dorcas%20et%20al%202010%20-%20Can%20pythons%20inhabit%20temperate%20regions.pdf
    The article also repeats that silliness about escaped and discarded pets, when the scientific evidence indicates they came from a pair that escaped when Hurricane Andrew bulldozed Homestead. http://www.usark.org/uploads/FloridaBurmGenetics.pdf
    Furthermore, she commits two stupid logical fallacies, deducing from their findings that 85 of 343 ( that is 25%) pythons dissected had bird bits in the gut that birds are 25% of the python diet. Second, that, therefore, pythons are a big threat to the birds. Anybody who has watched gators at a rookery knows that birds are a big part of the gators’ diet, too, and we would not be surprised to find bird bits in 25% of gators. We would expect to find bird bits in 100% of feral cats we may dissect!
    The facts Dove doesn’t have are percentages of bird mortality attributable to pythons, gators, raccoons, and other carnivores, including feral cats. The bias Dove and her co-authors have is the drive to pry loose our tax dollars for their personal and professional advancement.

  • slywolf77

    i thought those snakes where in the amozon never knew they where in the us. and a blue haroin those are big birds and in the glades must be bigger the the northern birds WOW!

  • John

    Mr. Townes,

    I read both articles that you posted and neither of them significantly refuted these claims. The temperature tolerance article explained that these pythons do live in temperate climates in their native areas and they showed that they could, in fact, adapt with proper underground shelter and thermoregualtory behaviors.

    The article on the genetics of ENP pythons was not conclusive and their lack of significant variation could be explained by the breeding practices of local Burmese Python dealers.

    Someone as educated as yourself should not resort to name-calling nor should you post journal articles in support of your views that don’t actually prove what you say that they do.

  • Harold

    First of all, “Burmese” pythons come from Burma, but no matter. I reading this article a couple of times and thinking, but I don’t think introducing an apex predator to Florida can be good. After a certain moment, even the alligators can’t handle them. On the other hand, they’re not American, and maybe North America is too hostile. Let’s hope. The tamarisk is a PEST in the desert!!: oases dry up when they move in!

  • Upyoursjack

    I know it would be hard. but a bounty on the heads of these pythons could also reduce the infestation