February 21, 2008—Caught like a convenience-store crook, a wild rat attacks a dummy egg during a surveillance camera-equipped experiment on California's Anacapa Island in 2003.

Alien rats—rodents introduced to places they wouldn't naturally live—are hunting down about 25 percent of all seabird species, a new global analysis says. (Read full story.)

About a third of all seabird species are listed as threatened or endangered by the World Conservation Union—and much of their demise is due to rats.

"Invasive rats are likely the single largest threat to seabirds," said study co-author Bernie Tershy of the University of California, Santa Cruz. The study was published in the February 2008 issue of the journal Conservation Biology.

The biologist is a past grantee of the Conservation Trust of the National Geographic Society (which owns National Geographic News).

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