Friday, November 13, 2009

Blog: Snake Break



Brahminy Blind Snake
I assumed after my last blog on the mongoose that its presence here explained the absence of snakes on Hawaii. But no, Hawaii has never had snakes (full disclosure: Hawai'i actually has had one native snake since about 1980, a Brahminy Blind Snake, which looks more like a worm than a snake, lives underground and is generally mistaken for an earthworm). It turns out unsurprisingly that being surrounded by water is a pretty good condition for not having snakes, e.g., there are also none in Ireland or New Zealand. Plus Hawaii works very hard to keep them out.
Then I wondered about Ireland because unlike Hawaii which is 2,400 miles from the nearest continental land mass, Ireland use to be connected to the UK by a land bridge and England has snakes. I then remembered that St Patrick had stood on a hill and charmed all the snakes on the island to go down to the seashore, slither into the water, and drown. Ur….hang on, isn’t that a fable? Well, it is – instead, when Ireland was covered by the last glacier which ended some 15,000 years ago all the snakes died as they did in England. But snakes were able to cross the English Channel to the UK from continental Europe by rafting across it on logs and such. However, the Irish Sea, which separates Ireland from England, is even wider and wilder than the Channel and posed a greater challenge to the snakes. The prevailing currents simply do not run in the right direction.

Back to Hawaii. Instead of turning out to be a light-hearted subject I learned that the islands are under considerable threat from the brown tree snake in Guam. Those interested should read the treatise done by Messrs. Kraus and Cravalho (Pacific Science, October 2001). It turns out the brown snake would be as bad as the mongoose to the Islands’ ecology! And the mongooses would not control the snake population because of access to easier prey.
Here is why the brown tree snake of Guam is so dangerous – again thanks to Fred Kraus, Hawaii Division of Forestry and Wildlife (http://www.state.hi.us/dlnr/Snake.html).
“The brown tree snake is a nocturnal and arboreal snake that ranges from eastern Indonesia to the Solomon Islands and northern Australia. After World War II it was accidentally introduced to Guam, apparently as a hitchhiker on military cargo returning from use in the war in New Guinea. In the next three decades the snake spread throughout Guam and eventually resulted in the extinction of nine of the island's twelve forest birds, half of its lizards, and perhaps some of its bats. It remains the leading cause of endangerment for the few remaining native vertebrates on Guam.
This snake has affected humans on Guam in a variety of ways too. Since 1980, Guam has suffered an average of one power outage every three days because the snakes cross power lines and short out the circuits. The island's previously thriving poultry industry has been devastated because the snake crawls into coops and eats the eggs and chicks. Many pet dogs and cats have been lost in a similar fashion.
Because of its secretive habits, the brown tree snake is adept at hiding itself in small spaces during the day and, consequently, is easily transported between islands in cargo shipments. Brown tree snakes have left Guam in this fashion several times, turning up in a variety of locations around the globe, such as Saipan, Wake, Tinian, Rota, Okinawa, Diego Garcia, Australia, and Texas. Between 1981 and 1994, seven brown tree snakes were accidentally transported to O`ahu in this manner and captured upon arrival. Most were found dead or dying near airport runways. As far as is known, brown tree snakes have not formed a self-sustaining population in Hawai`i. But constant vigilance is required to avert this disaster.
Because it has a similar climate and fauna, Hawai`i could expect to suffer many of the same negative ecological and economic consequences that Guam has if the brown tree snake were to become established here. Most of our remaining native forest birds would go extinct, power outages would probably be fairly frequent, and the tourist industry would possibly suffer from the negative publicity. To avoid this possibility, several state and federal government agencies have been working together for the past several years to ensure that the snake does not reach Hawai`i.
The first line of defense in keeping the brown tree snake out of Hawai`i involves the U.S. Department of Agriculture's program on Guam to keep the snakes out of the transportation network. This involves trapping and nigh night searches to remove snakes from port facilities, inspection of outbound cargo and vehicles with snake-detection dogs, and research into new ways to lower snake population levels on Guam. Searches of inbound planes and cargo are conducted by Hawai`i Department of Agriculture as an additional guarantee against snakes arriving into the islands. This is the second line of defense. As a final measure, DLNR has trained staff and groups of volunteers from other agencies in appropriate methods of finding brown tree snakes in the field. In the event of a likely brown tree snake report, these teams are called into action to search for the snake in an effort to ensure that any brown tree snakes that do arrive here do not have a chance to establish a self-sustaining population. Teams occur on each of the main Hawaiian islands.

You can help protect Hawai`i from brown tree snakes too. No snake species are native to Hawai`i (although the small, harmless blind snake has become established here this century), and all have the potential to become problems should they establish here. So if you see a snake anywhere in Hawai`i, immediately report it to the proper authorities, such as the Department of Agriculture (586-PEST) or the police. If it is safe to do so, it is best to kill the snake (e.g., drive over it, beat it with any blunt object, cut it in half with a machete) before calling. If not, keep the snake in visual contact until authorities arrive. A prompt response is essential to ensuring that the snake does not escape and can be captured by the proper authorities.”
For more information on brown tree snakes see http://reorg.nbii.gov/browntreesnake.
I wish this blog had turned out more upbeat, but this difficult, finicky, beautiful, wondrous planet has troubles everywhere, even in these incomparable islands which are certainly close to, if not, paradise. "Would that it were otherwise"

3 comments:

  1. As I read this article, it simply enforced one of the reasons I will be moving to Hawaii, it's wonderous lack of snakes. I however will not be keeping any snake within visual contact.

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  2. Wes - It's "would that it were otherwise".
    Good article on the snakes. That's why we had to find a new home for our 7' red-tailed boa before we moved to the island. ;-)

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  3. Thank you Liz....fixed the quote!

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Mahalo for leaving a comment!~WesIsland