The Brown Tree Snake on GuamHow the arrival of one invasive species damaged the ecology, commerce, electrical systems, and

human health on Guam: A comprehensive information source.

Thomas H. Fritts and Dawn Leasman-TannerU.S. Geological Survey

Fort Collins Science Center2150 Centre Ave., Bldg C

Fort Collins, Colorado 80526 USA

http://www.fort.usgs.gov/resources/education/bts/

How did the Brown Tree Snake get to Guam??

• Shortly after World War II, (and before 1952) the brown Tree snake was accidentally transported from its native range in the South Pacific to Guam, probably as a stowaway in ship cargo.

• As a result of abnormally abundant prey resources on Guam and the absence of natural predators and other population controls, Brown Tree Snake populations reached unprecedented numbers.

So what do they eat??

• Lizards• Birds• Small

Mammals

– The combination of extraordinarily high lizard densities, the main food source for young snakes, and birds has allowed the Brown Tree Snake to maintain densities of nearly 13,000 per square mile in some areas even in the absence of native birds.

– Having nearly depleted the bird populations on Guam, larger snakes have been found scavenging garbage and even sneaking in to steal a hamburger off the barbeque!

What do they look like?• Generally 3-6 feet in length in its native range, over 10 feet

on Guam (where food supplies are more plentiful and conditions for long survival ideal).

• long and slender, exceptional climbing ability and can pass through tiny spaces in buildings where it seeks undisturbed refuge during daylight hours.

• Venomous, but doesn’t really affect adult humans.• Variations in coloration

occur in the snake's native range, ranging from a lightly patterned brown to yellowish/green or even beige with red saddle-shaped blotches.

Where do they come from?• native to coastal Australia,

Papua New Guinea, and a large number of islands in northwestern Melanesia.

• The species occurs on both large and small islands, extending from Sulawesi in eastern Indonesia through Papua New Guinea and the Solomon Islands and into the wettest coastal areas of Northern Australia.

• snakes on Guam represent the only documented reproductive population outside the native range.

GuamHawaiian Islands

So what’s the problem with the Brown Tree Snake in Guam??

• Rapid decline and near extinction of most of the native forest vertebrate species

• thousands of power outages affecting private, commercial, and military activities

• widespread loss of domestic birds and pets

• considerable emotional trauma to residents and visitors alike when snakes invaded human habitats (their venom can also affect small children).

So what’s the problem with the Brown Tree Snake in Guam??

Just a few of the extinctions…

• The Micronesian kingfisher was extirpated from Guam by the brown Treesnake

Cryptoblepharus poecilopleurus (Snake-eyed skink)Cryptoblepharus poecilopleurus (Snake-eyed skink)Cryptoblepharus poecilopleurus (Snake-eyed skink)Cryptoblepharus poecilopleurus (Snake-eyed skink)

Hemidactylus frenatus (House gecko)

So what’s the problem with the Brown Tree Snake in Guam??

• Since Guam is a major transportation hub in the Pacific, numerous opportunities exist for the brown Tree snakes on Guam to be introduced accidentally to other Pacific islands as passive stowaways in ship and air traffic from Guam.

• Some brown tree snakes have been found on nearby islands – but not as bad a problem as people are watching out for them.

So what’s the problem with the Brown Tree Snake in Guam??

Transporting to other islands (not on purpose)

Controls• Canine Detection Teams• Physical Barriers• Trapping• Visual Searches• Habitat Modifications

Toxic Mice To Help Guam Fight the Brown Tree Snakehttp://www.youtube.com/watch?v=RjMx2r9nnZg&safety_mode=true&persist_safety_mode=1&safe=active