Diatribe: The Mice Of South Farallon Island.
We live in a country setting. The neighborhood is not particularly “rural” but there are woods and creeks and the houses are relatively far apart. The area attracts quite a bit of wildlife, including mice. Since they day we moved in we’ve always had a cat living with us. He’s done a good job of keeping our house a mouse-free zone with only the occasional sighting in the basement or garage areas that are off-limits to his roaming. I’m not afraid of the occasional mouse but tens of thousands like those found on South Farallon Islands would make me think again.
The pacific island, which sits only twenty-seven miles off the coast of San Franciso, is the most rodent-dense island in the world with an average of five hundred Eurasian house mice occupying each of its one hundred twenty acres … approximately sixty thousand mice! The only humans who have to deal with them are the scientists studying the otherwise uninhabited island’s unique ecosystem. The population has gotten so large that the ground often seems to be moving, and other species are being threatened.
Last Friday, the Fish & Wildlife Service released a six hundred fifty-page report that sums up its review of the forty-nine methods suggested for getting rid of the creatures that are thought to have arrived on the islands via nineteenth century seal-hunting vessels. The study determined that there are only two options … douse the island with poison or do nothing.
The house mice are predators of eggs from many sea birds, including species of concern to the state. There are only fifteen thousand Ashley Storm-petrels worldwide, for example, and half of which are thought to breed exclusively on the islands. Migratory owls head to the islands in the winter to feast on mice but, as the mouse population declines, they turn to seabirds for their diet.
Although other ideas including the introduction of feral cats, trapping and sterilization, the Fish & Wildlife Service has concluded that any method other than poisoning (which would involve treated food pellets dropped on the island that would ultimately cause the mice to bleed to death) would have too great an effect on the island’s ecosystem. Plus, by doing this, they would have to develop a method to keep peregrine falcons and burrowing owls as well as sea gulls from having access to the mice.
While mouse populations have been eliminated from more than fifty islands around the world using “rodenticides”, animal rights groups are opposed to the practice. They note that on the fifty islands where poisons have been used, other animals also perished and that one of the poisons under consideration was banned from sale this year by the EPA because it was so toxic to animals.
I’m inclined to say “leave ‘em alone”. Until this enormous mouse population makes it onto the mainland, and into someone’s basement, the problem isn’t really a problem to anyone other than the sea birds. Surely, the sea birds will find somewhere else to nest.
What do you think? Douse the Island with poisonous pellets? Or do nothing?
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