One of the biggest challenges in IPM is the management of invasive species. Most of the research that I write about involves attempts to reduce populations of invasive insects, weeds and sometimes diseases, to encourage the restoration of the resource the invaders have decimated. However, sometimes an article about IPM for mammals will pop up, such as an article in ScienceDaily about invasive Burmese pythons, I jumped at the chance to write a post about it.
Burmese pythons eat a wide variety of birds and mammals, from small birds and rats to animals as large as alligators and white-tailed deer. With no predators to keep them in check (in their native southeast Asia, they are classified as a “threatened” species), the giant snakes can reproduce and feed as they please. Recently a group of scientists from the Smithsonian Institution, U.S. Geological Survey and the National Park Service have discovered that the pythons can feed on something that before now was not considered part of the snakes’ diet: bird eggs. The scientists’ findings are reported in the March issue of Reptiles & Amphibians: Conservation and Natural History.
Burmese pythons began “immigrating” into the U.S. via the exotic pet trade in 1970 to be sold as pets. According to a Florida Extension publication, the snakes are popular pets because they are purportedly docile and have colorful markings. Unfortunately, some people who buy a 20-inch baby python don’t realize that within a year they will have to feed an 8-foot creature who can actually squeeze them to death. Unable to find the snake another home, some of these owners release the snakes into uninhabited areas or forests. Undaunted by the lack of predators, the pythons eat, find mates as other pythons are released, and multiply.
Park officials in the Florida Everglades first discovered and removed Burmese pythons in 1979. Until 2004, python numbers were small (less than 20), and officials were able to remove them manually. By 2007, however, about 418 pythons were removed or found dead, and the exponential increase in population numbers between 2004 (75) to 2007 meant that officials were finding only a fraction of the actual python population.
Until January 2011, wildlife specialists considered the Burmese python a risk mainly to fledgling and adult mammals and birds. In January 2011, however, when scientists from the South Florida Collections Management Center in the Everglades National Park examined the stomach contents of an adult Burmese python, they discovered two crushed bird eggs. The eggs were from a Limpkin (Aramus guarauna), a large water bird about the size of a Great Blue Heron.
In May of the same year, the Miami-Dade Fire Rescue Venom Response Unit discovered a Burmese python near a Guineafowl nest on a farm in Miami-Dade County. As the unit was transporting the snake off of the farm, the snake regurgitated a whole Guineafowl hen and ten eggs. Before these two incidents, scientists did not consider the Burmese python a threat to unhatched birds.
Snakes that eat hard-surfaced objects such as eggs (called egg-eaters) are rare, and egg-eating species have special bladelike elements on the spine, called hypapophyses, that can break the eggshell while in the esophagus. When scientists examined Burmese python organs, they discovered the pythons have hypapophyses. The discovery of the python’s ability to ingest bird eggs uncovers a new threat to bird species in the Everglades.
Want to help reduce the increase of the invasive snake population? The following list includes some ways that citizens can help stop the spread of invasive snakes or other exotic species often kept as pets:
- Before you buy any type of exotic animal, do your research first. Find out how big the animal will be as an adult, its feeding and exercise needs, etc.
- If you or someone you know can no longer care for an exotic pet, find someone who can or call your county’s wildlife division for advice on how to dispose of the animal. Do NOT set the animal free in the woods.
- Learn identify your state’s native snakes and tell them apart from exotics.
- Learn more about invasive species and download educational materials at http://www.nps.gov/ever/naturescience/floridainvaders.htm.