Sixty-three snakes have been confiscated, turned in to the state or caught in the wild in Hawai`i between July 26, 1994, and February 4, 1998. Only one of them was a brown tree snake, caught in a Schofield Barracks warehouse in December 1994. The rest were species commonly kept as pets on the mainland: pythons, boas, corn snakes, vipers, garter snakes, etc.
Why has so much attention been given to the brown tree snake and nearly none to the rest?
Are brown tree snakes more dangerous than the others to Hawai`i’s environment? Not necessarily. Are they more likely to settle here than other snakes? Again, not necessarily, especially considering how easy is it to smuggle snakes into Hawai`i.
Despite these considerations, the attention of state and federal agencies is likely to focus on the brown tree snake for some time to come, probably because of the devastation that the snake has wrought on Guam.
Guam’s invasion by the brown tree snake (Boiga irregularis) is one of the most notorious examples of what can occur when a snake colonizes an island that lacks natural defenses. The brown tree snake has been held responsible for the extirpation of several of Guam’s native forest birds, shore and sea birds, an insect-eating bat, and several lizard species. Declines in the populations of introduced birds, mammals, geckos and skinks have also been attributed to snake predation.
Brown tree snakes crawling on power lines have caused hundreds of power outages — about one every four days on average. The snakes, which are slightly venomous, have also preyed on poultry, pets, and have bitten more than 200 residents.
Native to Indonesia, New Guinea, the Solomon Islands, and Australia, the brown tree snake was accidentally introduced to Guam shortly after World War II, probably as a stowaway on a cargo ship. In less than 20 years, the snake established itself throughout Guam, reaching densities as high as 40 snakes per acre during the 1970s and 1980s. Between April 1981 and December 1994 seven brown tree snakes have been found in Hawai`i, two at the Honolulu International Airport, three at Hickam Air Force Base, one at Barber’s Point Naval Air Station, and one at Schofield Barracks.
Those Other Snakes
As much attention as the brown tree snake has received, programs to control its spread are generally acknowledged to lack sufficient resources. Still, they have the support of policies, control plans, and federal and state funds. No similar system exists for the other snakes that have been or could be found in Hawai`i, many of which pose a threat that could approach that of the brown tree snake.
In an October 1997 article in Bioscience, zoologist Gordon H. Rodda; Thomas H. Fritts, who coordinates federal brown tree snake programs on Guam; and University of Colorado professor David Chiszar point out that the reproductive output, dietary habits, ecology, and behavior of brown tree snakes are not unique. And because the brown tree snake is not unique, they say, herpetologists should strive to study a wider diversity of species, “particularly tropical species.”
The also stress: “For conservation biologists, the inference is that snakes can cause biodiversity crises in a wide variety of contexts. Prey species on islands seem to be especially vulnerable, but many prey species on continents also lack coevolutionary experience with nocturnal arboreal snake predators. If not B. irregularis, the culprit could be Boiga trigonata (a native of Asia), Trimorphodon biscutatis (a native of North America), or the deadly Trimeresurus flavoviridis (the habu, a native of Japan). These three snakes are, like the brown tree snake, venomous, nocturnal, and at least partially arboreal — but so are hundreds of other species.”
In a similar vein, Fred Kraus, a snake expert with the Department of Land and Natural Resources’ Division of Forestry and Wildlife, compares the threat of smuggled snakes to that of the brown tree snake in an article he co-authored recently entitled, “Newly Emergent and Future Threats of Alien Species to Pacific Landbirds and Ecosystems.” (Portions of the article are reprinted in this issue.)
The 63 snakes recorded captured in Hawai`i between July 1994 and February 1998 included several of the species Kraus discusses: eleven were boas, eleven were pythons, four were corn snakes (Elaphe), and there were two of the viper species and two were bull/pine/gopher snakes (Pituophis). “That these snakes have not elicited the same level of concern in Hawai`i that the brown tree snakes have is remarkable and probably attributable to the general ignorance of snakes and their biology that prevails at any location in which they are naturally absent,” Kraus concludes.
Considering the havoc that an accidental invasion can cause, the deliberate introduction of snakes into Hawai`i by people smuggling them in as pets poses a serious threat to the state’s economy and ecology. Unfortunately, Hawai`i laws and widespread ignorance about the threat of snakes limit the state’s efforts to stop smugglers.
Under Hawai`i law, officials of the Department of Agriculture — the state’s lead agency in controlling snakes — cannot seize or confiscate any prohibited or restricted animal at will. According to Larry Nakahara of the DOA’s Plant Quarantine Station, the agency’s inspectors have authority to “pick up a snake like any other regulatory agency, but like any other law enforcement agency, we must follow the rules of search and seizure,” which entail applying to a judge for a warrant and then executing it.
Nakahara says the DOA also cooperates with the attorney general’s office, military police, and the U.S. Fish and Wildlife Service in enforcing state laws against the importation and possession of alien species. These agencies have the authority to enforce the laws, he says, but at the DOA, “We don’t have arrest powers.”
For the DOA to establish an enforcement arm of its own, Nakahara says, state law would need to be changed. But, he adds, “That’s not necessary because we do have all these law enforcement agencies. It’s not a problem getting assistance. We have to develop a case [in order to get cooperation], but it’s not the authority that’s missing.”
The U.S. Fish and Wildlife Service has helped the DOA block the importation of piranha and with the capture of a snake in Waianae, Nakahara says. Under federal conspiracy law, penalties are available for importers of illegal items, including snakes.
But, according to Eugene Hester, senior resident agent for the Fish and Wildlife Service, federal law can only go so far. His agency only gets involved in an investigation at the behest of the state, he says. In any case, “most of the snakes that are found are simply found in the wild or turned in through the [state’s] amnesty program, so we haven’t had a great deal of involvement” with state enforcement efforts, Hester told Environment Hawai`i.
Smuggling busts are handled on a case-by-case basis, Nakahara says. The Department of Agriculture has no ongoing program to deal with smugglers. Instead, Nakahara says, each investigation “depends on the kind of information that we get and who needs to be called in. If we get an anonymous tip about a possible smuggler we do a background check on the person. The attorney general’s office will pursue anonymous tips, but you have to build up a case. Which agencies will be brought into play depends on the details of each case and on which agency has greater authority for certain things.”
Educating the Bench
Even when smugglers of snakes are caught, there is no assurance that penalties commensurate with the crime will be imposed. Nakahara cites two cases that went to court. Working with the attorney general’s office and the Honolulu prosecutor, the defendants were convicted and the maximum penalty — a $25,000 fine and a year in jail — was imposed. But in one case, the fine was reduced to $2,500 and jail time was waived so long as the defendant wore a tracking device. In the second case, the fine was reduced to $2,500, although jail time remained one year.
For this, Nakahara blames a judiciary that has yet to be adequately educated about the dangers that would be posed if a snake population becomes established in Hawai`i.
“There certainly needs to be education at judicial level,” Nakahara says. Judges “need to impose a satisfactory penalty that matches the importance of the crime…. [Possessing a snake] may not be as problematic as killing a child, but if a snake becomes established, it has far-reaching effects.”
Mail Call
“The Silent Invasion,” an educational booklet published by the Coordinating Group on Alien Pest Species (CGAPS), describes another example of the state’s inability to prevent snake smuggling: “Limited resources and the U.S. Postal Service’s mandate to deliver mail without delays greatly limit the inspection of Hawai`i-bound mail, in spite of evidence that the mail is a common pathway for live animals, insects, and weed seeds.”
DOA Plant Quarantine inspector Lester Kaichi, who coordinates the state’s canine quarantine inspection teams, agrees. In the case of people who smuggle animals by mail, he says, “we’re dealing with people that are trying to outsmart the system. Their chances are better…. First-class mail, based on the Fourth Amendment, is protected from inspection.”
A spokesman for the U.S. Postal Service in Honolulu verified Kaichi’s claim. Without a court order, Kaichi could not inspect a package suspected of carrying a restricted animal, nor could he record the name and address of the intended recipient, the spokesman said. It is a violation of postal laws to mail dangerous animals, including poisonous snakes, he went on to say, but if the smuggler doesn’t elect to announce his contraband cargo to the Postal Service, that law is hard to enforce.
Intercepting passengers who are carrying snakes is no easier than tracking contraband that comes by mail. “If you had a snake in a bag, there’s no way I would know,” the DOA’s Kaichi says. “And you’ve got 200 on people each flight, each with handbags, backpacks, suitcases. If you knew the system, and you wanted to smuggle in a snake, you could put it in your jacket, or in some kind of cloth container, strap it to your body, get off the plane, walk straight to the curbside and nobody would touch you because all the inspectors are at the baggage area.”
How feasible is it to inspect passengers to deter smuggling? “If you were the governor or in charge of the Hawai`i Visitor’s Bureau, I don’t think you’d like the idea of setting up such a restrictive area at the airport that you become like U.S. customs,” Kaichi says. “It would be detrimental to tourism.”
Serpent Sightings
Roughly one third of the snakes caught or received by the Plant Quarantine Station between July 1994 and February 1998 were turned in under an amnesty program that allows people to surrender illegal animals and plants without penalty. Three were confiscated. The rest were found in the wild. That means at least 63 snakes (and probably more) wriggled their way to Hawai`i through inspection loopholes.
Over this same period, there 60 reports of snake sightings where no snake was found. Not all reports are reliable. “A lot are worms, centipedes, slugs, radiator hoses on the highway,” Kraus says. “Half of them aren’t snakes at all.” Still, that leaves about 30 reliable reports of snakes that have not yet been caught.
Late last year, Maui was a hot spot for snake scares, the most notable being the discovery of a 15-foot long python skin — belonging to a snake probably 12 to 14 feet long — and remnants of a smaller boa constrictor skin in Makawao.
For eight days, from January 6 to 14, DLNR employees, DOA officials, and volunteers from Haleakala National Park, the Nature Conservancy, and Haleakala Ranch literally beat the bushes of Makawao for any sign of the snakes to which these skins might have belonged. After officials determined that the skins belonged to snakes not in Hawai`i, but in Utah. A former Makawao resident now living on the mainland called state officials after hearing about the snake searches. He said he had been given the skins by his brother in Utah, who owns the snakes. He had kept the skins in his garage and had noticed them missing after a garage sale held shortly before his move back to the mainland.
While the search didn’t turn up any snakes, state officials still regarded it as productive, with the attendant publicity having helped educate Hawai`i residents a little more about the threat snakes pose.
Cruising
About a month before the great snake hunt, a 2-foot-long, light brown, unpatterned snake was seen crossing Hansen Road near Pu’unene. That became the seventh snake sighted in three months between Kahului Airport and Makawao.
According to an article in The Maui News of December 5, a 3-foot ball python was captured in a Makawao garage on September 18. “Other sightings have been reported in Central Maui cane fields as well as the Kalama Hill area of Makawao,” it states.
These cane-field sightings of large snakes by sugar workers prompted state officials in November 1997 to begin regular searches of the fields. Leading the searches are state wildlife biologist Fern Duvall and Lloyd Loope of the National Park Service, assisted by volunteers. Hawaiian Commercial & Sugar Co. has allowed Tuesday-night hunts to be conducted on their land nearly every week since then. Between 6 and 9 p.m., searchers systematically patrol sugar cane roads, focusing on areas closest to the sightings.
According to Duvall, old cane fields are ideal for harboring snakes. There is abundant cover, water from irrigation systems, and plenty of food — mainly rats.
The searches have turned up no snakes. Since December, there have been no more sightings of snakes in cane fields.
To address the many cane field sightings, Duvall consulted with herpetologist Earl Campbell, who works with the U.S. Department of Agriculture’s Animal Damage Control Division. Campbell advised Duvall to conduct a systematic search of the roads. “If we find a snake by that method it will give us a lot of information about the snakes, most likely a python or boa constrictor,” Duvall says. “If we can find the species, then maybe we can hone our search methods.”
The searches are, at best, a shot in the dark, Duvall acknowledges. Still, cruising along roads is a time-honored method of searching for all kinds of snakes in conditions of low visibility, as exist in with dense sugar cane, according to Gordon Rodda, a zoologist with the U.S. Geological Survey who has worked extensively in Guam on the brown tree snake. This type of search is also done on Saipan, where brown tree snakes are thought to have become established.
Right now, there is no designated source of funds for searches of snakes other than brown tree snakes. To do the job right would take about $50,000 a year, Kraus estimates.
Trapping
Trapping is another method employed by the DLNR in an effort to catch snakes. Traps are baited with live animals, usually mice. In response to the Hansen Road snake sighting, for example, the DLNR set 60 such traps.
Most snake experts will admit this is not a terribly effective means of catching snakes. It is done not because of high expectations of success, but rather to make certain all possible avenues are exhausted. Nor is the ineffectiveness of traps difficult to explain. As Duvall notes, prey densities (that is, rat populations) are so high in cane fields, getting a snake to enter a baited trap would almost be a matter of dumb luck.
Traps are somewhat more effective in Guam. Kaichi explains: In Guam, brown tree snakes have wiped out most food sources and are looking for anything to eat. “In the wild, most of the birds are gone so they basically feed on lizards and whatever else they can find. That’s why they go in the trap. In Hawai`i, you go out there right now, you see a lot of birds. What snake is going to enter a trap when it can catch its own bird in the tree?”
Traps are also expensive to maintain. Each trap needs live bait that must be fed and changed on a regular basis, Kaichi says. “That’s a lot of manpower to go out there and put a new mouse in every other trap, check the food, make sure they’re getting their water supply and make sure the traps are not damaged,” he says.
In its arsenal against a snake invasion, the state also has dog teams. The problem here is that the dogs are not trained to track snakes, but only to look for snakes in cargo and aircraft. Training the dogs to follow a scent along the ground is not feasible, Kaichi says.
Other possibilities include physical barriers, fumigants to treat cargo containers, and biological control. All are still in the early research stages, and almost all of these are focused on the brown tree snake.
A Lucky Strike
On January 10, 1998, the state got lucky in its search for a ball python. According to Kaichi, if a snake is not caught within minutes of its sighting, it is most likely the snake will not be caught at all. However, the python, spotted by hikers in Kalihi on January 9, was captured despite search teams arriving on the scene several hours after receiving the report.
The sighting call came in at 7 p.m., which did not bode well for a search. “There’s no way you’re going to find a snake in the forest at night,” Kaichi says. The searchers had to wait until morning. To everyone’s surprise, the snake was found. It had been wounded, so could not travel far from where it was first spotted. “If that was a healthy snake, I don’t think anybody would have found it,” Kaichi says.
With response time being such a critical factor, how long does it take to mobilize searchers? According to Kaichi, it can take as little as half an hour. If it looks as though it will take longer than two hours for Department of Agriculture personnel to arrive at the site of the spotting, other agencies are called in to help. These might include the state Department of Land and Natural Resources, military personnel, or volunteers trained by the DLNR to hunt for snakes. (The Fish and Wildlife Service cannot use funds to assist in searches unless the snake is suspected to be a brown tree snake.)
Team Work
With a constant stream of flights arriving in Hawai`i from Guam, state, federal and private agencies have joined forces to try to prevent the establishment of the brown tree snake in Hawai`i.
The Brown Tree Snake Control Committee was formed in May 1993 to address the snake problem in Hawai`i, as well as Guam and the Mariana Islands. The committee produced a plan in June 1996 to address the various needs each party had for controlling the brown tree snake.
At the local level, the Brown Tree Snake Technical Committee, also consisting of federal and state agencies and private organizations, advises only the Hawai`i government on how to run its programs more efficiently. According to Kaichi, the committee is trying to develop a plan “to present to whoever will listen on how we want things done as far as keeping the brown tree snake out of Hawai`i.”
Some objectives include more research, beefing up Hawai`i’s inspection program, and maintaining Guam’s program. “We want one plan that all the agencies agrees to so there won’t be any competition for money,” Kaichi says.
Another group established to foster cooperation in the fight against invasive alien species is CGAPS, or the Coordinating Group on Alien Pest Species. CGAPS members include the state Departments of Agriculture, Health, Land and Natural Resources, and Transportation; and an array of federal and private organizations, most prominent of which is The Nature Conservancy of Hawai`i, instrumental in bringing the coalition together.
CGAPS has produced “The Silent Invasion,” an educational brochure that describes the threats alien species pose to Hawai`i and includes top-ten list of Hawai`i’s “most unwanted” pests. The brown tree snake is listed as number one. No other snakes appear on the list.
To address the threat of these remaining snake species, no formal organization exists. Rather, representatives of various agencies have been discussing this only informally among themselves.
According to Kraus, “In the last several months we’ve reached a consensus to address snakes other than brown tree snakes.” Until then, he adds, “people weren’t taking the problem seriously.”
Getting people to agree that other snakes are a problem and getting them to devote resources to search for them was “a big first step,” Kraus says.
And according to Dave Worthington, a biologist with the U.S. Fish and Wildlife Service, getting people to agree is not easy. Discussing the Brown Tree Snake Technical Committee meetings, he says that between the Brown Tree Snake Control Plan, the Brown Tree Snake Prevention Plan, and the Brown Tree Snake Response Protocol, which all involve interagency cooperation, “we spend half the meeting discussing how to make things work.”
Duvall stresses the need for public education, in addition to agency enlightenment. More people need to know that Hawai`i is, or at least is supposed to be, snake free, Duvall says. “We always run into people who didn’t know that,” he says.
“The other thing is I know is that on Maui, there are 45 federal agriculture people who guarantee that no fruits get into California,” he says. “Yet there are only seven state staff people to look at harbors, freight and aircraft. That discrepancy needs to be worked on.”
— Teresa Dawson
Volume 8, Number 9 March 1998
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