I’d like a small island without so much rat in it

Invasive species are a major problem in our modern world. That’s because we’re generally happy with the way things are and less happy when some vagabonding drabcoat like a starling or a wild pig or even a smallish purple thistle moves in and starts carpeting the place. Also, frequently enough, the invaders got a lift over from us, and so we feel a lingering sense of guilt over the whole fiasco, at least those of us who haven’t made pots of money off not worrying about it.

And so it has gone with pigs, goats, cane toads, zebra mussels, nutria, rabbits, eucalyptus, kudzu, privet, tamarisk, all manner of ballast-water hitchhikers, brown tree snakes, lake trout, fire ants, house finches, leafy spurge, scotch broom, big jellyfish, uncomfortably large sea urchins. There’s even evidence we were carting fruit bats from island to island nearly a thousand years ago, for God’s sake.

And then of course there’s the original: the rat. The consummate invader has made mincemeat of island oddities ever since the first one dragged its creepy hairless tail off a sailing ship and started infiltrating nests of helpless birds (like the flightless kakapo, a New Zealand parrot the size of a toddler).

But today’s post isn’t about bad news. It isn’t about scurrilous rats with their insatiable appetite, their lust for expansion, their pyramid schemes and gleaming steel shrines to capitalism. It’s about community, faith, and grit. A small band of determined locals. And a shearwater.

Wedge-tailed shearwaters nest, among other places, on a 3-acre scrap of lava off O’ahu, Hawai’i, called Mokoli’i Island, in burrows that they somehow etch into the rocky soil. Unfortunately, rats have burrows pretty well figured out, and in the years 1999-2001 exactly one shearwater fledged from all the nests on the entire island.

Some University of Hawai’i researchers enlisted the help of concerned locals and started an e-rat-ication campaign in earnest. By May 2002, the team had scattered 354 blocks of poisoned bait, captured 18 rats, and could find no lingering ratty traces on Mokoli’i.

That same year the island’s shearwaters produced 126 young. For those of you who are impressed by large percentages, that’s a 37,800 percent increase (over the previous annual rate of 1/3 of a shearwater per year). The next year the tally went up another 50%, to 185. The researchers also noted, though a bit less scientifically, a definite increase in tidepool animals, native plants, and an endangered grass after the rats were removed.

There you are, some good news for a change. Now, if we could just get the rats out of the other 33.3442 billion acres (not counting Antarctica) of land on the planet.

Images: thanks to the University of Hawaii’s Project Ant (a whole other story in itself) and the USGS… and in other shearwater news: last week we found out that the sooty shearwater flies 40,000 miles in a lazy figure-8 around the Pacific every year, the longest animal migration yet documented.

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