Like spring, fall in the Bay Area is marked by subtleties. A slight change in the angle of sunlight, a slight chill in the air, a few dry brown leaves skittering around on the ground. It is now officially fall. A seasonal sign I eagerly await is the sound of geese honking their way across the sky toward their winter homes in the Central Valley and coastal bays. It is not unusual in Oakland to wake up on an autumn morning to hear geese in the air. Where do these geese live in the summer? Way up north in Canada and Alaska, and as far north as Wrangel Island in Russia. They breed and molt in and around lakes and ponds, fly to warmer climes before their food is lost to ice, and return to the Arctic in spring to start the cycle over again.

The smallest and fastest of the geese is the Pacific black brant. On its southward migration along the Pacific Flyway it travels up to 3,400 miles nonstop from Alaska to Baja California in just two and a half days.

Each spring and summer, about 30 percent of the world's population of 110,000 Pacific black brant gather around Teshekpuk Lake, a high arctic wetland complex on Alaska's North Slope, within the 23.5-million-acre National Petroleum Reserve–Alaska. Up to 90,000 geese molt in this area and up to 46,000 caribou use it for calving and migration.

Because of its enormous importance to waterfowl, as well as caribou and other wildlife, this area has been accorded special protection. In 1977, the Carter administration designated 1.7 million acres of the wetlands around the lake as the Teshekpuk Lake Special Area. In 1983, the Reagan administration closed 200,000 acres north of the lake because of its value to molting brant and other geese. Since then, human presence has been allowed there only for scientific research and exploration.

In January of this year, the George W. Bush administration approved oil and gas drilling within about 500,000 acres of the Special Area. The Bureau of Land Management (BLM) scheduled a lease sale for September 27. Fortunately for the geese, the U.S. District Court for Alaska stopped the sale two days before bids were to be opened. The court found that the BLM's environmental analysis failed to consider the cumulative impacts of widespread drilling.

This is a welcome reprieve, and we can hope that it's the end of a foolish plan.

Studies have shown that molting brant are highly sensitive to disturbances, especially to aircraft. At the sound of a helicopter, they attempt to escape; being flightless at this stage, they may try to walk overland to other water bodies, leaving their food source behind and exposing themselves to predators.

Oil drilling in the brants' summer home would come as a double whammy for the species, which is already being threatened by global warming. No place on earth is seeing the effects of climate change more dramatically than the high Arctic. According to a report by the U.S. Geological Survey's (USGS) Alaska Science Center, climate change seems to be driving higher rates of coastline erosion and higher storm surges that intrude into arctic lakes and make them salty, robbing geese of freshwater habitat.

"The Pacific Flyway is but a corridor connecting the wetlands of the West," naturalist and author Peter Steinhart has written. In California we have been doing what we can to help the brant and other migrating waterfowl. "What you do in California," said a researcher at the USGS Alaska Science Center, "affects birds up here and has a synergistic effect on the brant population. Many California bays are important to the brant--Humboldt Bay especially so because of its abundant eelgrass beds."

Brant are interdependent with eelgrass. They graze it, fertilize it, and keep it healthy. "When eelgrass is scarce in winter, fewer brant nest and raise young the next summer, and the population declines," said the scientist. Other species that rely on the habitat are also affected, including salmon, crabs, and myriad smaller species. This is one reason among many the Coastal Conservancy has been involved in efforts to restore eelgrass in many of California's coastal bays and estuaries.

The brant population had been declining during three years of El Niño conditions that caused erosion and saltwater intrusion in bays used by brant in Mexico and California. One heavy consequence was damage to eelgrass. Last winter, conditions were favorable to eelgrass and the brant population rose slightly.

The Teshekpuk Lake Special Area is especially vital to molting brant. It has few predators and its shore habitats provide nutrients for feather growth. Some birds fly up to 1,000 miles from southern Alaska, Russia, and Canada to molt there.

If El Niños become more frequent, as is being predicted because of climate change, the birds may breed less often and skip flying to wintering areas in Mexico, wintering in California instead. The importance of the high Arctic lake, and of California bays and eelgrass, will keep rising.

We hope that someday we will have a national government that takes climate change as seriously as California and many other states now do. I worry about the geese's future, and my own. We can ill afford to lose a harbinger of spring and fall.

Sam Schuchat is the executive officer of the Coastal Conservancy.