MURRES are ... sensitive. The 20th century has been rough on them, and even the 19th century ended badly. The murres' biggest, bustlingest breeding colony is on the Farallone Islands, just north of San Francisco. As many as six million murres nested there in the early 1800s. In the late 1850s, however, the Farallone Egg Company started harvesting murre eggs. The chicken population couldn't keep up with the burgeoning human population of California, so the murre eggs were gathered to meet the demand. Since the birds do not breed until they are four to six years old, and since each pair produces just one egg per season, egging quickly threatened the colony. The egg company battled over land rights with the federal government, which claimed the Farallones as lighthouse territory. Federal marshals hauled the eggers off the island in 1896.
     Left alone with the lighthouse keeper and a few other human companions, the murres began to mate their way back to a recovering population. Growing technological progress begat pollution, however, when oil tankers started plying the coastal waters between southern California and San Francisco Bay. The ships regularly flushed their tanks at sea, trailing miles-long oil slicks where murres bobbed in the waves.
     Marine birds unlucky enough to be coated with oil meet with a shop-of-horrors variety of gruesome ends. Birds that inhale or swallow toxins from freshly spilled oil suffer pneumonia and kidney and liver damage. Oil on an eggshell poisons the developing embryo inside. Floating oil coats birds' feathers, ruining their insulating effects and weighing the birds down. The birds die from drowning, hypothermia and exhaustion.
     In the 1920s, after documenting oil's threat to marine birds, environmental groups, including the Audubon Society, and the U.S. Biological Survey worked with oil companies to build on-shore tanks to store waste oil. Since then, ever-stricter environmental laws have protected marine life from most intentional oil pollution. Nevertheless, accidental spills threaten wildlife each year.
     Gill nets, the murre's latest foe, snag and drown murres and other diving birds. The wide nets, dragged behind boats, gained popularity in the 1970s, but federal, state and regional restrictions now force gill net fishers far off shore. The past decade has been relatively peaceful for the murres, and their numbers have increased to 50,000-100,000 at the Farallone breeding site.
     The mock murre colony at Devil's Slide Rock, populated by decoys and serenaded by stereo equipment, mimics a real colony so well that several live, randy murres have decided to join the crowd. A few murres settled down at the colony during the project's first year, and some laid eggs. Last year, the third year of the repopulation effort, nine breeding pairs made Devil's Slide Rock their home, and 30 other non-breeding birds hung out at the colony. Some of the murres, who can live more than 20 years, were probably members of the original colony wiped out by the oil spill. Seeing their native breeding grounds once again teeming with life, they may have decided to give Devil's Slide Rock one more chance. Last year's breeders will almost certainly be back this year, since murres return loyally (even romantically) to sites where they have bred successfully.

AFTER SETTING out the first flock of decoys two weeks ago, some of the biologists returned to see what kind of response their faux-murres would elicit. With muscles still aching from the previous day's climb, they trained their binoculars on Devil's Slide Rock from the highway and counted 30 murres.
     "This feels like a colony," says Carter, who has studied murres for 20 years. Murres fly around the cove and swim near Devil's Slide Rock. The birds are waiting for the biologists to leave so they can have a little privacy. As the biologists hover over their wooden chicks and eggs, a California gray whale surfaces 30 feet from the rubber boat. "Holy mackerel!" yells Carter, spinning the Zodiac around for a better look.
     San Pedro Rock, where murres last nested 90 years ago, frames the other end of the cove. The murre biologists decided that since the Devil's Slide Rock colony is attracting murres so successfully, they should try to repopulate San Pedro Rock as well. Once the rock climbers have nestled the last decoy chicks and eggs into place on Devil's Slide Rock, Carter picks them up and ferries them across the cove.
     Boyce leaps into the Zodiac laughing. She says that she still loves the work, even after three seasons of climbing around on the guano-frosted rock. "Maybe after the fourth season I'll get tired of it," she says over the growl of the outboard engine.
     They haul more supplies in from the patiently watching Queen of Hearts. Carter darts the Zodiac up to San Pedro Rock in between crashing waves, and Nothhelfer heaves solar panels, decoys, and 50-pound batteries up to Parker, balanced precariously on the rocks. After all of the supplies and scientists have been delivered, they painstakingly ascend San Pedro Rock and place decoys all around. They anchor the mirrors and position the loudspeakers, preparing to cast another spell.
     Murre populations have plummeted in many of their historic nesting areas, but the birds are wide-ranging. In the Pacific Ocean, they breed from Big Sur up to Alaska and along the Asian coast down to Japan. In the Atlantic, they nest from Maine up through Canada and down through Scandinavia, Britain, France and Portugal. Throughout the range, oil pollution and gill netting have killed the birds or forced them from their historic breeding grounds. Devil's Slide Rock and San Pedro Rock are close enough to an surviving colony, the one in the Farallone Islands, that murres find the decoy colonies and may be persuaded to homestead there.
   Carter doesn't envy the biologists trying to help the California condor recover. In 1987, when the last birds were captured and introduced into a captive breeding program, only 27 condors were alive. "That's why we want to do this now," says Carter of the murre restoration project. "We want to bring them back before it's too late, while we can still make a difference."

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