Showing posts with label invasive pythons. Show all posts
Showing posts with label invasive pythons. Show all posts

Sunday, April 8, 2012

Florida Pythons Confirmed Consuming Limpkin Eggs

Two Limpkin (Aramus guarauna)
crushed but intact eggs (top; EVER
44949) recovered from a Burmese
Python digestive tract and compared
 to a reference Limpkin specimen
(below; USNM 25786) for size and
color patterns. The arrow shows
fragments of eggshells from the
python sample placed on the
 museum specimen for color
comparison. Photograph by Don
Hurlbert, Smithsonian Institution.
Smithsonian scientists and their colleagues have uncovered a new threat posed by invasive Burmese pythons in Florida and the Everglades: The snakes are not only eating the area’s birds, but also the birds’ eggs straight from the nest. The results of this research add a new challenge to the area’s already heavily taxed native wildlife. The team’s findings are published in the online journal Reptiles & Amphibians: Conservation and Natural History.

Burmese pythons, native to southern Asia, have taken up a comfortable residence in the state of Florida, especially in the Everglades. In addition to out-competing native wildlife for resources and habitat, the pythons are eating the native wildlife. Burmese pythons (Python molurus bivittatus) were 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.

In an ongoing study to better understand the impact of this snake in the Everglades, scientists from the Smithsonian Institution, the National Park Service and others have been examining the contents of the digestive tracts of pythons in the area. They have shown that Burmese pythons consume at least 25 different species of birds in the Everglades, but until now no records documented this species eating bird eggs.

“This finding is significant because it suggests that the Burmese python is not simply a sit-and-wait predator, but rather is opportunistic enough to find the nests of birds,” said Carla Dove, ornithologist at the Smithsonian’s Feather Identification Lab in the National Museum of Natural History and lead author of the study. “Although the sample size is small, these findings suggest that the snakes have the potential to negatively affect the breeding success of native birds.”

Scientists collected a 14-pound male python that was 8 1/2 feet long near a property with free-ranging guineafowl. The snake regurgitated 10 whole guineafowl eggs soon after it was captured. The team discovered the remains of two bird eggs in another python collected for the study―a 30-pound female more than 10 feet long. Scientists used DNA tests on the membrane of the crushed eggs and comparisons of the shell fragments with egg specimens in the Smithsonian’s collection to determine what the female snake had eaten. Their research revealed the species to be the limpkin (Aramus guarauna), a large wading bird found in marshes and listed as a “species of special concern” by the Florida Fish and Wildlife Conservation Commission.

There are several species of snake known to eat bird eggs. Those species are equipped with pointed or blade-like extensions on the vertebrae in their esophagus that punctures the eggshell, making it easy for the snake to crush the egg and digest its contents. Burmese pythons do not have these adaptations. However, the pythons studied were so large in relation to the eggs they ingested that the scientists believe these specialized vertebrae may not have been needed.

“Our observations confirm that invasive Burmese pythons consume not only adult birds but also eggs, revealing a previously unrecognized risk from this introduced predator to nesting birds,” said Dove. “How frequently they are predating on bird eggs is hard to know.”

In an earlier stage of the study, the scientists collected more than 300 Burmese pythons in Everglades National Park and found that birds, from the 5-inch-long house wren to the 4-foot-long great blue heron, accounted for 25 percent of the python’s diet in the Everglades.

Tuesday, April 3, 2012

Training Dogs to Find Florida Pythons

Time is carrying the following story.

“Sit. Speak. Good boy. Now go find a snake that can swallow a 76-pound deer.”

Trainers at Auburn University in Alabama have put Labradors on the scent of Burmese pythons—those Asian snakes that are running amok in the Florida Everglades. In recent years, the Sunshine State has tried to curb the population’s numbers, but pythons are “notoriously hard to find and very secretive,” as one biology professor puts it. That’s where EcoDogs could come in.

Todd Steury, a conservation professor who co-founded the EcoDog program, describes an EcoDog as “a bomb-detection dog that’s trained to find something other than bombs.” This might be scat (read: animal poop full of biological information), destructive fungi or, as of 2010, snakes big enough that they attempt to eat alligators whole. “Pythons don’t belong in South Florida,” Steury says. “And they eat everything. I literally do mean everything. The only inhabitant of Everglades National Park they haven’t found inside a python is a Florida panther.” That may be hyperbole, but the snakes have been linked to declines in native-fauna sightings.

The inevitable question is, of course, are the dogs in danger of being eaten by these voracious creatures? Steury says the trainers take extra steps to minimize that concern and notes that a python big enough to attempt such a meal is rare indeed, despite stories of 16-footers that become ingrained in our pop-culture memories.

The dogs are bred at Auburn University and maintained by the veterinarian school, where they are all given basic obedience and detection training. Before being put on python patrol, a dog is first introduced to the scent, captured by rubbing coffee filters on the snakes. The dogs are taught to associate tracking that scent with a toy, their reward, before finally being trained to “fringe.” When fringing, a technique also used with delicate newborn fawns, the dogs follow a smell toward its source but stop before they get to the source itself.

Without dogs, seekers are left to “put together these teams of humans who stand elbow-to-elbow and move through the environment, kicking up grass and hoping to find pythons,” Steury says. “The thing is, these snakes are so good at hiding, you could be standing on top of one and not even know it. So that’s where these dogs are really useful.” The EcoDogs’ inaugural trip to Florida took place over six months during 2010 and 2011. Whether there will be a second still depends on financing and Florida officials deciding how they want to tackle their python problem.

Meanwhile, let us all bow before the incredible feat of nature that is the canine nose. Venerable sniffer, we salute you.

Saturday, February 18, 2012

Another Large Python bivittatus from Everglades NP

The following is from the National Parks Traveler webiste. The story is dated February 17, 2012.

A Burmese python more than 16 feet in length and tipping the scales at 140 pounds has been captured at Everglades National Park, evidence of the problem park officials face with the spread of these non-native constrictors.

The female snake was captured Monday after a park staffer came upon it while spraying non-native vegetation.

Park officials say that "many national parks struggle to manage the impacts on resources by invasive exotic animals and plants, but it seems that the Burmese python in the Everglades has captured the attention of the media and the public on this issue, which may help to focus attention on the larger invasive exotic problem that many land managers are grappling with."

"The park has spent the past few weeks emphasizing to the media and the public the importance of not letting unwanted animals or plants loose," notes Everglades spokeswoman Linda Friar. "It is important to focus on what we have learned from this experience to prevent future invasive exotic infestations and improve our ability to react quickly before a species becomes impossible to eradicate."

While pythons have been a problem in Everglades National Park for much of the past decade, the situation garnered heightened media interest recently due to a study blaming the snakes for a "precipitous declines" in mammals that once were commonly seen in parts of the park.

Though members of the park’s staff are working on containment and science to better understand the impacts of this newest exotic in the park, it appears that eradication is currently not possible on a landscape the size of the park (almost 2400 square miles), Ms. Friar wrote in a release.

Friday, November 18, 2011

More Opinions on Invasive Pythons

The Orlando Sentinel web site is carrying an opinion piece on the Everglades' python problem this morning that seems to be motivated by photos of large snakes eating deer. The writer states,
"Last year, the Legislature sought to wrestle some control by banning the import, sale, breeding and possession as pets of six species of large constrictor snakes. The problem, though, is that breeders can still possess, breed and import the slithery troublemakers for their business. That leaves Florida, and its wildlife and habitat, still vulnerable. It's people, too — as we saw with the tragic 2009 death of a Sumter County 2-year-old, crushed to death in her crib by a starving family pet python that tried to eat her. 
"It's time the Sunshine State get an assist from a more authoritative source — the White House. The Obama administration has been sitting on a proposed rule to ban the interstate transport and importation throughout the country of the most harmful constrictors, those identified in a 2009 U.S. Geological Survey as posing the most risk to America's natural resources."
 The U.S. Fish and Wildlife Service proposed to target eleven species of large constrictors in March including some not currently banned under Florida law. Two, or more, of the  species have already established populations; and, some see these snakes as serious threat to the Florida panther and Key deer as well as other native wildlife.

While I can appreciate the writers' viewpoint. The python is already out of the bag. Preventing future colonization and contributions to the already established gene pool is useful, but the real damage has already been done. The pythons are already established. If there are any lessons to be learded from Guam's brown tree snake invasion, its that invasive snakes probably can not be eradicated once they are established.

Monday, March 14, 2011

Pythons & Birds in the Everglades

You knew this was coming. The following press describes the research documenting the damage invasive pythons are doing to bird populations in Everglades National Park.

Scientists find that non-native snakes are taking a toll on native birds

Python bivittatus. JCM
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.

"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 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.

"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."

Dove, C. J., R. W. Snow, M. R. Rochford, F. J. Mazzotti. Birds Consumed by the Invasive Burmese Python (Python molurus bivittatus) in Everglades National Park, Florida, USA. The Wilson Journal of Ornithology, 2011; 123 (1): 126 DOI: 10.1676/10-092.1