Birds Return to a Rat-Free Island

A small seabird is rebounding now that the rodents are gone.

Scripps's murrelets are faring much better on California's Anacapa Island now that the black rats are gone, according to a new study in Biological Conservation. The rats, which eat the eggs of these small, crevice-nesting birds, likely arrived on the island in the mid-19th century, and nearly wiped out the murrelets. By 2002 the National Park Service and the nonprofit Island Conservation had eradicated the rats with poison. Thanks to the program, the first of its kind to track long-term murrelet populations in response to an invasive predator, nesting success nearly tripled, from about 30 percent in 2001–2002 to 85 percent in 2003–2010. Using poisons this way is certainly controversial, yet "it's a viable option for this type of bird," says lead author Darrell Whitworth. "Each island is its own special case."