Tuesday, February 09, 2010
Poisoning Lord Howe Island
Lord Howe Island
As I have noted in the past, rats are responsible for more animal extinctions than any other cause. The chief victims have been birds native to small tropical islands. Rats prey on both eggs and baby birds and, in some cases, adult flightless birds as well.
For this reason, rat poison may be the the single most important equipment in the world of bird conservation -- though using the right type in the right manner and in the right location is critical. In the wrong hands, rat poison can not only kill rats and mice -- it can kill birds, small native animals, fish, pets and even humans.
Now comes word that the government of Australia intends to helicopter 42 tons of rat poison to Lord Howe Island, 370 miles off the coast of Australia, in order to wipe out black rats that first came to that island on a ship in 1918. Lord Howe Island is considered to be one of the most beautiful places in the world.
Since their arrival, rats have wiped out four species of endemic birds and the Lord Howe Stick Insect. The Lord Howe Stick Insect was considered extinct for 80 years until a handful were found in the leaf litter under a single bush on "Ball's Pyramid," a small, very steep, nearly nude rocky escarpment of an island several miles away from Lord Howe Island.
If the rats can be wiped off of Lord Howe Island, the goal is to breed and reintroduce the large Stick Insect back to its native land.
The Lord Howe rat eradication effort will involve capturing and caging native birds -- along with penning up dogs, cats, cows, and chickens -- in order to transport them all off the island for a period of 100 days while the poisoning operation is in full swing.
Rats have been eradicated from islands only a few times before, and in all occasions, it has involved a tremendous amount of poison bait used for a long time.
It's worth remembering that the rat is a survivor -- they survived the nuclear blasts on Pacific atolls and actually prospered under those conditions, living on dead creatures and plant life that washed up on the beach.
One of the few examples of successful rat eradication on an island is Campbell Island, south of New Zealand. Rats got to the island via whaling ships, and destroyed the nesting grounds of the flightless teal and wading duck.
In 2002 the government of New Zealand used 120 tons of rat poison on the island (over 240,000 pounds), delivered by boat and helicopter. About 200,000 rats died, but not without some mishap. A tanker carrying 18 tons of rat poison sank in a whale breeding ground, and there was some temporary contamination of the local mussel population.