60 years after they found their way to the shores of Guam, brown tree snakes have become the island's most pervasive invasive species. Now believed to number in the millions, the unwelcome serpents have decimated the region's wildlife, slithering around without having to worry about any natural predator. Faced with this unchecked threat, experts have teamed up with an unlikely ally in the battle against snakes -- scores of parachuting mice laced with a lethal payload.
Authorities from the US Geological Survey believe that the snakes first arrived in Guam, a US territory in the west Pacific, hitching a ride by boat or plane during World War II. Since then, the snakes have proliferated on an unimaginable scale by feasting on the island's native bird species, and their population growth left unchecked shows no signs of slowing.
The snakes, which are mildly venomous, have caused many problems. They get everywhere, and people have even woken up with them in their beds.
The island's power system is regularly shorted out by snakes crawling on the lines. It is so frequent the locals now call power cuts "brown outs".
But the biggest impact has been on the wildlife - it has been decimated. The forests here are eerily quiet. Now the only place where the Guam's native birds, such as the koko, can be seen on the island are in cages in a captive breeding centre.
"The brown tree snake has had a devastating impact. Ten out of 12 native forest bird species disappeared in 30 years," reports Cheryl Calaustro, of the Department of Agriculture. "The birds here evolved without predators. They were quite naive. And when the snake arrived on Guam it ate eggs, juveniles, adults. Whole generations disappeared."
Brown tree snakes, an invasive species, on Guam have nearly wiped out all native birds and other native wildlife. Photo courtesy: Wikipedia
As conventional methods of controlling the snakes have done little to squelch the island's 2 million or so brown tree snakes, conservation officials have begun experimenting with a more creative approach.
From the BBC:
One effort has involved air-dropping mice that have been laced with poison and fitted with parachutes out of helicopters. It provides a deadly dinner for any unsuspecting snakes below.
"Right now we are using acetaminophen (paracetamol). It commonly used as a pain reliever and fever reducer in humans, but it is 100% lethal to all brown tree snakes," explains Dan Vice of the US Department of Agriculture.
"If they eat that dead mouse containing acetaminophen, they will die."
It was about this time, after reading this, that I had a crazy flashback to a promotion a Radio Station ran many, many years. They were going to allow the good citizens of the city the opportunity to hunt their own Thanksgiving dinner just like the pilgrims did - they were going to release live turkeys onto the streets of the city. The birds were free to anyone who caught one.
There was only one real problem with the plan. They decided to release the birds from a helicopter. It didn't take long for them to realize that turkeys can't fly.
It just seems to me that pushing things - dead or alive - out of helicopters never seems to work out as it was intended.
If the move seems rooted in desperation, that may be because it is. In the last six decades, brown tree snakes have transformed Guam's island ecosystem, perhaps beyond repair.
Elmo, the Jack Russel is an expert at sniffing out snakes. Photo courtesy: bbc.co.uk
Efforts to eradicate the brown tree snake population on Guam and prevent them from hitching a ride to another destination are vigorous.
In a busy cargo depot close to the airport, Elmo the Jack Russell, kitted out in a smart, green uniform, is sniffing box upon box of goods waiting for export.
He is on the hunt for any unwanted stowaways.
As he catches wind of an unusual scent, he begins to scrabble, alerting the government inspector to the presence of a snake - and is rewarded with a treat.
A small army of dogs check every single item of cargo before it leaves Guam.
"It is a monumental project. We're working 24 hours a day, seven days a week," says Mr Vice.
"Cargo doesn't stop, the airport doesn't shut down, so we have to be there to make sure the cargo going on the airplane has indeed been snake inspected."
Letting the snakes on a plane could have devastating consequences. After all, look what happened when a brown tree snake hitched a ride to Guam.