Long-billed dowitchers like this one have full plumage when they’re breeding, but they lose feathers on their migratory stopovers. Without their flight feathers, they can’t fly long distances or avoid predators. Tim Fitzharris, Minden/National Geographic
Migrating birds are weakened or sickened as they wing their way along the Pacific flyway in search of fresh water.
By Jane Kay, National Geographic PUBLISHED July 16, 2015
Suisun City, California—In years past, long-billed dowitchers flying in from Alaska could count on California stopovers to offer vast stretches of fresh melted snow teeming with plants and insects. But now, as the Sierra Nevada snowpack has vanished and clouds offer little rain, few lush sanctuaries are available to sustain these shorebirds on their journey along the avian highway known as the Pacific flyway. Experts say that once the dowitchers arrive in the Central Valley this month, their prospects look bleak. Along the 4,000-mile-long Pacific flyway—one of four main routes in North America for migrating birds—up to six million ducks, geese, and swans wing south every year to find warmth after raising young in the rich habitats of Alaska, Canada, and Siberia. They are joined by millions of shorebirds, songbirds, and seabirds, including the ultimate endurance winner, the arctic tern. But California’s drought has dried up its wetlands. Many insects, fish, and plants are gone. As a result, some migrating birds have died or been depleted of so much energy that they have trouble reproducing. Thousands of ducks and geese, crowded onto parched rivers and marshes, are felled by botulism and cholera, which race through their feeding grounds. Drought and deluge are part of the natural cycle of life in California. But species that have migrated for thousands of years on the same routes since glacial sheets melted at the end of the Pleistocene now struggle to adapt to human-managed water supplies in the backdrop of a globally changing climate that exacerbates dry spells. “The longer droughts are the worst. At first, the energy deficits from too little food affect the weaker or younger ones. In back-to-back droughts, even the strong birds get pushed to the limit,” says Blake Barbaree, an avian ecologist at Point Blue Conservation Science, a nonprofit research center in Petaluma, California. The Pacific flyway cuts through interior California and along the state’s coast, through habitat that has vastly changed after four years of severe drought and decades of water diversions. Sandhill cranes and greater yellowlegs flying from Anchorage, Alaska, will reach the Kern National Wildlife Refuge near Bakersfield only to find a mere trickle….