Everglades Pythons Exhibit New Behaviors

Melissa Farlow

Everglades Pythons Exhibit New Behaviors

Despite new regulations, snakes in Florida continue to cause destruction.

By Daisy Yuhas
Published: 03/08/2012

Exotic snakes are regular visitors to Laura's farm, a mere 500 yards from the edge of Everglades National Park. Last summer, when she called Miami-Dade county rescue service to report an eight-foot python, however, she didn't realize she was contributing to a scientific discovery. The snake on her property would reveal to biologists a totally new behavior in the invasive snakes wreaking havoc in the Everglades ecosystem.

A response team arrived and guided the snake--a Burmese python--into a sack. The team brought it to Miami-Dade Fire Rescue, but along the way, the python, jostled during transport, regurgitated a whole guinea hen and 10 intact eggs.

"Not only are these snakes eating bird young--something our native snakes do--but they might also threaten adults, which most native snakes do not because of the birds' sizes," says Everglades National Park wildlife biologist Skip Snow, who examined the snake at the lab. "And now eggs."

The story will appear in a note to be published in the journal IRCF Reptiles and Amphibians. It's one of three instances described by Snow and his co-authors of a Burmese python eating birds' eggs, and it marks the first time scientists have ever documented the behavior. The discovery may mean that this invasive species is causing more damage to Everglades birdlife than previously imagined.

"We thought these snakes would sit and wait for prey to come by," say note lead author Carla Dove of the Smithsonian Institution Natural History Building Division of Birds. "But maybe they're roaming around and eating everything in their way."

Not only is egg eating unheard of in the species, the snake's anatomy makes it a particular challenge. The Burmese python is not equipped with the sharp toothlike projections in its throat that allow other snakes to crack open eggshells, meaning the python has to digest the eggs with shells intact.

In March, Dove and Snow, along with the University of Florida's Michael Rochford and Frank Mazzotti, published a study showing which bird species pythons prey upon. By opening the digestive tracts of 85 pythons collected in Everglades National Park between 2003 and 2008, they discovered that the snakes consume at least 25 species, including the endangered wood stork and the snowy egret.

Based on these kinds of studies, birds make up about a quarter of the Burmese python's diet. The bulk of its prey--some 75 percent--is mammals, and one percent is comprised of American alligators, the snake's only known reptilian prey. Nonetheless, many questions remain.

"We really don't know yet what the impact is," says Mazzotti, who recently contributed to a study linking steep mammal declines in the Everglades to an increase in the python population. "But the impact on birds is particularly difficult to study."

Mazzotti and his colleagues are trying to decipher that now. Using cameras, they're monitoring wading bird habitats to see what happens when pythons strike. Rails and marsh birds appear to be particularly common prey, probably because pythons are opportunistic predators and their habitat and behavior overlaps with those of these birds.

Understanding how pythons affect Everglades wildlife is only half the battle; managing this invasive species is the other. Although massive--up to 25 feet long in captivity--the snake is elusive, virtually invisible amid the millions of acres of Everglades vegetation. From 2007 to 2011 the park service removed more than 1,400 pythons. But the snakes are quick to adapt to new habitats, consume any prey available, and lay large clutches. The first Burmese python was spotted on the boarder of the Everglades National Park in 1979; today tens of thousands of Burmese pythons may live there, most of them born in the park's sawgrass marshes, swamps, and forests.

The snakes are also strong swimmers, comfortable near human habitation, tolerant of a range of salinity, and able to adapt to climates cooler than South Florida. So far they have moved into the Florida Keys, but some biologists say they could easily thrive across the southern third of the United States--and that range that could be extended depending on the future effects of climate change. In January, in part because of these predictions, Interior Secretary Salazar announced a ban on the importation and cross-state transportation of four snake species--including Burmese pythons, northern and southern African pythons, and the yellow anaconda--that threaten the Glades*.

Critics fear the ban is too little, too late. Environmental lawyer Jane Graham, who is now an Everglades Policy Associate for Audubon of Florida, previously published a survey of existing laws to prevent the influx of invasive species. Finding these laws lacking, Graham made proposals modeled on systems from around the world. She advocates stronger risk assessment, screening measures, and allowing entry to preapproved species only.

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Daisy Yuhas

Type: Author | From: Audubon Magazine

Comments

Such sniping I do not

Such sniping I do not understand ! If there is 1-100 or 1000 they do not belong in he wild in south Florida. It seems to me the stomach content studies are pretty hard evidence and speak for themselves. The overall message of the article is they do not belong so how do we control the numbers ?

Since when is a guinea hen

Since when is a guinea hen native to Florida?

And, just who mentioned the

And, just who mentioned the Guinea hen is native to Florida?

Burmese pythons

Failed to mention that these animals were protected by the government until just recently. The cold snap we have had in the last to winters 2010 and 2012 killed many of these snakes. You failed to mention with the new law's if Florida some people released more animal's. Real estimates on the number are between 1500- 2500 animals found in only two counties. You should read the February Chicago Herpes bulletin and the comments by Dave Barker.

Incorrect Facts

While I will not touch on the rest of the article, other commenters have done that, there is a glaringly large flaw in your article.
"In January, in part because of these predictions, Interior Secretary Salazar announced a ban on the importation and cross-state transportation of four snake species—including Burmese pythons, northern and southern African pythons, the yellow anaconda, and the boa constrictor—that threaten the Glades"
You have FIVE species listed. Boa Constrictors have not been added to the lacy act. Next time, please double check your references. I'm disturbed that such a large error made it into publication.

Correction

Thank you for taking the time to read the story and comment. We've made the correction in the piece.

I used to really value the

I used to really value the articles you wrote and thought of them as factually based. However, it just looks like you are jumping on the HSUS band wagon of shoddy "science" and unproven "facts". I'm disappointed in you.

ad hominem

Huh? You're just calling this a "bandwagon" and name calling without any explanation. You make no argument other than that you don't agree, I guess. I'm not sure why you dislike the Humane Society, but just because something is potentially bad or invasive, and this is mentioned in an article, doesn't mean it's a sensationalistic article.

As I find it interesting as a

As I find it interesting as a scientist that these snakes are eating bird eggs, I also find the assumptions you make about this invasive population alarming and disheartening. You show only one side of the argument about this species and do not site the other studies done on this snake that show the species is unable to move further north. I also agree with the other person who posted on here. Shame on you Audubon.

Adapting?

In January of 2010 - 53 female Burmese Pythons with tracking devices were found dead in the Everglades after a lengthy cold snap. So how is it the lower 1/3 of the United States is suitable habitat? The co-author of Mazzotti's paper has already back tracked and suggested they were not suggesting mammal population declines were caused by pythons, they were simply offering data and allowing others to draw that conclusion. Nice science. That whole study was terrible science. They compared road kill counts in the ENP to Ranger data on roadkill in the 90's. Different methods. Different environmental conditions. The pythons ARE a problem. But sound science and rational reporting needs to lead the fight against them. Not sensationalism.

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