MIGRATING BIRDS HIT HARD BY CALIFORNIA’S DROUGHT
It says something about the complexity of California’s water crisis that there are so many actors in the state’s water wars, all clamoring for more. Nature, alone, is silent in this fight, relying on others to speak on behalf of the welfare of wildlife and waterways.
Across the state, biologists, farmers and hunters are lending nature a helping hand. It’s sometimes an extreme intervention: trucking young salmon when drought shrinks rivers.
But this year these lifelines aren’t enough. Migratory birds — protected by state and national laws and an international treaty — are suffering mightily during this drought, even more quickly
than they did during the last major dry spell, which lasted five years and ended in early 2017.
California is the most critical link in the 4,000-milelong Pacific Flyway, a route along the West Coast where millions of birds shuttle between their summer and winter homes. It’s an arduous journey, hopscotching from wetlands and waterways, allowing birds to rest and refuel, shoring up strength for their trip.
Wildlife experts say this year’s severe drought has uncoupled that connectivity. Normal routes — long imprinted in migrating birds’ navigation systems — have gone haywire.
The great dryness has eliminated many of the flyway’s rest stops in California
— particularly in the far north Klamath region — forcing ducks, geese, eagles, herons and other traveling birds to stay aloft and keep looking. Biologists in Northern California and Oregon say they are tracking flocks deviating far off established flight paths, seeking water where there is little.
Experts say evidence is already emerging a year into this drought that their labored journey is weakening and stressing birds that struggle to find wetlands along their journey to rest and feed.
This year is the driest on record in the Lower Klamath Basin, a lush region of marshes and streams that straddles the Oregon-California border. The refuges there are “almost completely dry,” said U.S. Fish and Wildlife Service spokesperson Susan Sawyer.
As a result, nearly all of the ducks have vanished. A recent aerial survey of the vast refuge showed about 34,000 ducks this year compared to 1.5 million in 1948; nearby Tule Lake refuge had only about 30,000 ducks in the survey, down from 3.5 million.
In the span of a few human generations, even in years of plentiful rain, 90% of California’s wetlands have disappeared to development and agriculture, so migrating birds are especially vulnerable to prolonged droughts.
“The journey, from the human perspective, is enormous,” said Andrew Farnsworth, who researches bird
migration at the Cornell Lab of Ornithology. “It requires a lot of energy. Some start in Alaska. Flights of 4,000 miles are absolutely quite common, and they will fly nonstop for a few days. Having the resources they need is critically important.”
Melanie Weaver, waterfowl coordinator for the state Department of Fish and Wildlife, has confidence in the ability of migrating birds to adapt, saying “ducks and geese are wired to go through drought. They don’t fall out of the sky. They have wings, they move where food and water is.”
But the widespread nature of this drought throughout the West, and its severity and potential duration, may challenge even the most resilient wildlife.
“I’m concerned that we are not going to see the populations come back,” Weaver said. “This drought is bad. The odds are against us.”
Even recent winter storms — which dumped rain across the north and central parts of the state and swelled some rivers and streams — made no dent to ease California’s drought, wetlands loss or water shortage.
Resilient but still struggling
Resting and feeding spots at wildlife refuges are overcrowded this year, which can foster spikes in the infectious or waterborne illnesses spread by close quarters. Avian botulism and cholera, present even in wet years, spike in arid times. A botulism outbreak in the lower Klamath Basin last year killed an estimated 60,000 birds, likely many more.
So far the Klamath refuges have not experienced a severe disease outbreak like the one that took place last year. “But the spring could be a different story if birds leave the Central Valley early and return to the Klamath where there is little to no available habitat,” Sawyer said.
Klamath’s marshes, streams and grasslands provide vital stops during birds’ long journeys — more than 80% of migratory birds on the Pacific Flyway use them as a stopover in spring and fall. But the region has been one of the hardest hit in this year’s statewide drought.
Instances of young birds being “stranded” are amplified during drought. Dabbling ducks, which includes mallards and pintails,
nest in upland areas and must walk to water sources. During dry periods those marches can be too long for young birds that have no flight feathers so they can’t survive. Biologists say this happens all over the state, even in normal years, but is more common during drought.
While the Klamath region is the hardest hit, wetlands farther south on the flyway are in bad shape, too. At the Sacramento River National Wildlife Refuge, the October bird count is not encouraging. By the third week in October last year, the rough waterfowl count was nearly 800,000 birds. This year, it was 600,000.
And, to illustrate how the intensity of this drought is coming sooner than the last: The refuge’s geese population today is less than half than it was for the same month in 2015, which was the region’s worst year during the last drought.
Biologists talk about the resilience of birds, hardwired to just keep pushing on, but there is little good news now and even less for the near future. The National Audubon Society estimates that two-thirds of North American birds are at increasing risk of extinction because of climate change.
That vulnerability is repeated around the world: Only 9% of the planet’s migratory birds have protected areas along their routes, and loss of habitat and climate change is “a contributing factor to the decline of more than half of the migratory bird species across all major flyways in the last 30 years.”
Migrating birds, which a century ago filled the sky and blotted out the sun during trips along California’s long spine, need help.
To make the state more hospitable to migrating birds during the drought, state and federal programs are paying farmers to keep water on their fields. The state Department of Water Resources invested $8 million this fall. In the northern end of the Central Valley, agricultural land is flooded and managed as migratory bird habitat for
exhausted annual travelers flapping in from as far away as Alaska and Russia.
But the amount of water from rivers and lakes allocated for wildlife refuges has been cut back substantially this year. The Lower Klamath Refuge has been operating with half its water allocations from rivers and streams since 2006, but this year has been devastating: It received less than 1% of its allocations.
With the loss of more than 99% of its wetlands, few chicks were born in the refuge this year. Most birds didn’t bother stopping there to nest, moving instead to refuges the Sacramento area, which received 75% of their usual water allocation.
“This past summer there was extremely reduced waterfowl reproduction on the (Klamath) refuge due to the very limited available habitat,” Sawyer said.
Diagnosis: drought
The juvenile golden eagle, tagged as No. 2-21-0824, lay splayed on his back on a stainless-steel necropsy table at the state Wildlife Health Laboratory north of Sacramento. He had been discovered dead in Bakersfield, on the ground and emaciated, and taken to a wildlife rescue organization. His carcass was placed in a black trash bag, frozen and sent by FedEx to Krysta Rogers, head of avian investigations for the state fish and wildlife agency.
Rogers’ job is to discover what caused the young bird’s death. She selected large pruning shears, the sort gardeners might use to lop off a large tree branch. With a loud crack, she snapped the bird’s femur, setting aside a section of bone for further analysis.
Methodically examining the carcass, Rogers knew that the bird was not among the uncounted animals to succumb to drought-related causes. Instead, the young bird’s death was a case of bad housekeeping. It’s likely that the eagle’s parents brought home meals of especially fatty squirrels, Rogers said. The fat coated the bird’s wings, rendering it unable to fly. In a final blow, it’s possible that his nest-mate pushed him out of the family home to keep the food to itself.