Craig Springer

Consider that the Guam flycatcher is extinct, not seen since 1984. Consider the Guam rail is in serious decline, down to 0.2/100 kilometer from 80.4/100 kilometer in 1976. Consider that geckos are extirpated from Guam. That's hard data, but the lasting effects of the gaping hole in the ecological web may not manifest for some time to come.

It's difficult to predict the outcome, but the cause is well-known--the invasive brown tree snake, boigus irregularus. With densities as high as 13,000 per square mile and an estimated 1 million of the snakes on the island, this non-native predator has all but wiped out some endemic fauna. Only three of Guam's 13 native species of forest birds remain.

As seed dispensers, pollinators, and insect predators, all of these animals played a vital role in Guam's ecosystems. In addition, the snake has caused significant economic damage through its propensity to crawl onto high voltage cables in pursuit of perching birds. Since 1978, more than 1,600 blackouts have been caused by the snake, intermittently disrupting nearly every facet of civilian and military life on the island.

But there's more at risk than South Pacific islands far removed from the continental United States. Domestic and military ships and planes, leaving the island of Guam have put other areas outside the snake's present range at risk. To help coordinate plans to address a possible invasion of the continental United States, Bob Pitman, the Region 2 Aquatic Nuisance Species coordinator, hosted The Brown Tree Snake Conference to mobilize concerned agencies.

"There's a good way to get in front of any invasion," noted Pitman. "It's to prevent it from happening in the first place. And that's the purpose of holding the conference."

Cathy Short, the area director for Fisheries and Habitat Conservation and Aquatic Nuisance Species Task Force co-chair, could not agree more. "Prevention, prevention, prevention," said Short in her opening remarks to the June conference in Houston. "It's far easier to prevent the invasion of a nuisance species than to try eradication later."

Eradication can be costly, if not wholly ineffective. The snake has been ecologically disastrous in Guam, and there are lots of good reasons to prevent its invasion elsewhere. This species poses a human health risk and has caused millions of dollars in damage from power outages.

The brown tree snake is adaptable and could establish itself in the United States, particularly in the southern tier of states. In south Texas, snakes turned up in military cargo sealed for several months. In Florida, Service law enforcement intervention kept brown tree snakes from entering the pet trade.

Conference participants represented the network of professionals--from pet trade representatives to academicians--that will help to prevent this insidious invader from getting a foothold in the United States.

"Prevention means we have to work together to keep this nuisance off our doorstep," said Pitman. "Coordination, cooperation, and communications--that's what it will take and that's what we'll achieve through this conference."

"We have to keep this snake at bay," added Short. "It's hard to imagine a south-Texas birding trail without birds--the silence would be deafening."

To keep brown tree snake out of cargo leaving Guam, a number of methods have been employed--snake fences, traps, and flexible nylon netting tilted to prevent snakes from climbing aboard. Jack Russell terriers sniff out unwanted hitchhikers, but keeping dogs is labor-intensive and expensive. Traps baited with mice are effective, but also labor-intensive. Fumigants, like methyl bromide, rousts snakes out of cargo. Toxicants like caffeine, aspirin, and acetametphin hold promise. Educating the public, be it the pet trade industry or military personnel, may go a long way in preventing the spread of the brown tree snake.