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Davis, California

Sunday, May 26, 2024

Sandhill cranes are relying on us to provide their wintering habitat

Migrating cranes turn to farmlands and preserves to make up for wetland loss in the Central Valley

The Sandhill cranes start out as black strands on the horizon — just silhouettes against a hazy pink sky. They drift down into the flooded fields at sunset with their feet below them, like parachutists.
They stand in the water the same as they did thousands, even millions, of years ago. Only the vineyards weren’t there, or the houses, the road, the freeway, the cyclists or dairy farms. The water was full of life in their untouched habitat. The sky was clear all the way to Mount Diablo.

Several years ago, I came across a National Geographic social media post, which featured a photo of cranes in an open meadow at twilight. I was surprised to realize that the photo was taken in my hometown of Lodi, Calif.
I followed National Geographic to ogle over places like Holland and landmarks like the Iguaza Falls. Here, I was looking at cutesy “Livable, Loveable Lodi,” a small town known for its wine and unofficially titled “the Zinfandel Capital of the World.”
I grew up seeing the Sandhill cranes represented in regional art and poetry. I would watch them flying over the freeway at dusk on my long commute home from school. But it wasn’t until this year that I finally made it out to see the cranes at the Isenberg Crane Reserve.
They foraged and called out to each other between the reserve and an adjacent field. A lone heron wandered between families of two and three birds. The cranes mate for life and usually travel with their young until they are 10 months old.

“The family unit is very important to Sandhill cranes,” said Jane Adams, a volunteer docent with the California Department of Fish and Wildlife. “They take parenting very seriously. The chicks are born in May or June, and they have to be ready to fly in September. […] Migration isn’t something instinctual. They have to be taught.”

“They’ve been on the earth for a long time, so I treat them kind of like a spiritual totem,” says Colleen Moss, a docent with the California Department of Fish and Wildlife who has lead crane tours for over 20 years.

According to the International Crane Foundation, a crane fossil found in Nebraska dated 2.6 million years old and could “be structurally identical to the modern Sandhill crane, making it one of the oldest known bird species still surviving.”
The Sandhill cranes vary in size, depending on their subspecies, says the International Crane Foundation. Lesser Sandhill cranes weigh 6 to 7 pounds and stand 3 to 3.5 feet tall. Greater Sandhill cranes weigh 10 to 14 pounds and stand 4 to 4.5 feet tall.
They are known for their unique song-and-dance routine, which attracts birdwatchers in droves to the Central Valley. They have a distinct call — kar-r-r-o-o-o — which has been compared to a bugle or a trumpet. Together, their voices form a chorus of prehistoric sounds. Mating pairs of Sandhill cranes sing together in coordinated duets.

“The Sandhill crane’s call is a loud, rolling, trumpeting sound whose unique tone is a product of anatomy,” said All About Birds, The Cornell Lab of Ornithology site. “Sandhill cranes have long tracheas […] that coil into the sternum and help the sound develop a lower pitch and harmonics that add richness.”

“That’s what gives [the call] its trilling sound,” Adams said.

They also perform elaborate dances — running, leaping, bowing and flapping their wings.

“They jump straight up in the air,” Adams said. “They dance a lot. […] They also will throw sticks up in the air.”
“They are large, vocal, spectacular birds with unique breeding displays and have become symbols of international cooperation for bird conservation,” said the U.S. Fish and Wildlife Service site.
Greater Sandhill cranes migrate exclusively to the San Joaquin-Sacramento Delta area, according to Moss.

“In 1940, there was five nesting pairs left — that’s the Greater Sandhill cranes,” Moss said. “By putting the land back in conservation, we’ve put the numbers back to 5,000.”

The Isenberg Crane Reserve land formerly belonged to the El Dorado Duck Club, until the property gained protection as an ecological reserve by the Fish and Game Commission in the 1980s, according to Moss.
“The Sandhill crane population declined sharply in California in Gold Rush days, when the birds were sold like turkeys in San Francisco butcher shops,” said Denis Cuff in the Contra Costa Times. “But in the past two decades, its population here has stabilized, with the help of new, crane-friendly farm practices that have helped preserve its habitat.”
They are threatened by other factors now.

“The once threatened Sandhill crane has made an inspiring comeback throughout much of its range,” said the International Crane Foundation. “However, despite this success, the species continues to be threatened by power line collisions and wetland loss.”
“California has lost approximately 90 percent of its natural wetlands areas,” said Kayla Webster in an article posted to the Natural Resources Conservation Service California site in July 2016. According to Peter Tira, the public information officer for the California Department of Fish and Wildlife, it’s 95 percent.
Areas once composed of wetlands have been converted to orchards and vineyards that disrupt the Sandhill cranes’ ability to land and forage for food.

“The Greater Sandhill cranes have a wingspan over five feet, and they can’t land in the grapes,” Moss said. “If they got scared or spooked, they couldn’t take off from there.”
Due to wetland destruction, “The Greater Sandhill crane population has diminished in California to a point where they were listed as a threatened species in 1983,” said the Woodbridge Ecological Reserve (Isenberg Crane Reserve).
In some ways, agriculture in the Central Valley has helped crane populations by providing residue crops of corn, grain and wheat.
“The farming really hasn’t been bad for them. They will eat the leftover grain,” Moss said. “The birds kind of help out because they are adding fertilizer to the fields and they’re eating pests. They aerate the soil with their beaks.”

In California, The Nature Conservancy works with wildlife preserves, like Cosumnes River Preserve, to provide habitats for wintering birds.
“The Cosumnes River Preserve consists of over 50,000 acres of wildlife habitat and agricultural lands owned by seven land-owning Partners,” said the Cosumnes River Preserve. “The habitat supports wildlife, including birds that migrate throughout the Pacific Flyway.”
“The Nature Conservancy partners with farmers, government and nonprofit groups to manage crops, grasslands and water to provide food and shelter for cranes and other birds on the Pacific Flyway migratory path,” Cuff said.

“They own Staten Island,” Adams said. “They practice farming that continues to provide habitat and water for cranes — as well as other birds.” Staten Island is an island on the Sacramento-San Joaquin River Delta and provides the wintering habitat for 15 percent of the cranes who migrate to the Central Valley.

“For decades, farmers burned their fields after harvest, a cheap way to destroy crop residue and control disease and pests,” said Liza Gross, a science contributor for KQED. “But the practice, which generated hazardous air pollutants such as hydrocarbons and sulfur dioxide, was banned in 1991. Farmers turned to post-harvest flooding to decompose husks and stubble in their fields with the happy albeit unintentional consequence of creating high-quality habitat for water birds like the crane — a result that may explain why millions of water-adapted birds still use the region each year despite the catastrophic loss of wetland habitat.”

“Generally, row and field crops as well as pasture land is good surrogate foraging habitat for cranes,” said Mark Ackerman, a biologist at the Bureau of Land Management Wildlife at the Cosumnes River Preserve.

The cranes typically arrive at Cosumnes River Preserve in early September and return to their breeding grounds in March.
“In general, the Preserve including the conservation easements provide all the necessary sheltering and foraging habitat needs for the cranes,” Ackerman said.

“[The Cosumnes River Preserve is] crucial for cranes. They come to the Central Valley to winter,” Tira said. “They need a place to rest and fuel up for migration. […] We’re lucky in the Central Valley to be able to experience the cranes in fall and winter […] We’re the epicenter of the Pacific Flyway.”
Tira said that most farmers enjoy seeing wildlife on their property. “It’s a win-win if we can all work together.”

Farmers may even be paid incentives for flooding their crops for migrating birds, according to Ker Than, a science journalist.
At the Isenberg Crane Reserve, less than 10 miles from Cosumnes, busloads of tourists visit the cranes annually during Lodi’s Sandhill Crane Festival.
“We’ve seen 3,000 birds come in at sunset,” Moss said.

“Open marsh, flooded pasture and grassland at site support Greater Sandhill cranes,” says Isenberg’s site. “Between late afternoon and early evening the ‘Crane Fly-in’ can often be seen as cranes fly into the surrounding flooded fields to roost for the night. The haunting sounds of the approaching cranes can be heard from miles off.”

“It was the most awe-inspiring animal spectacle of my life,” Adams said in reference to the first time she saw the crane fly-in.

“The Sandhill cranes are just amazing to go and watch,” said Lisa Sears, a Lodi resident who enjoys watching the crane fly-in with its amazing sunsets and views of Mount Diablo. “I look out and see all the birds, the cranes, ducks and egrets. All the birds share this space together without conflict. It’s very peaceful, and it’s a nice way to end the day.”

While farming in California has reduced wetlands and the cranes’ wintering habitat, in the Central Valley, smart farming can reduce the loss of resources by providing suitable surrogate habitat and food sources.
“Cranes and farms can co-exist,” Gross said. “But loss of habitat remains a concern, as the past decade has seen more vineyards and orchards move into grain fields historically used by cranes. With most wintering cranes concentrating on private lands in the valley, the future of this Pleistocene throwback will depend on the willingness of landowners to work with biologists to manage the land with wildlife in mind.”

Conservationists and biologists agree that supplying the Sandhill cranes’ wintering needs will be a cooperative effort.
Since agriculture has vastly changed California’s landscape, it’s important that farmers, scientists and the state government work together to provide for wildlife.
“I see it as beneficial to have the wetlands back,” Moss said. “I think the importance of having a natural space to go to, it benefits both the cranes and people. It’s like taking care of your soul.”

“We have to realize these birds have literally been coming to the Central Valley for thousands of years,” Adams said. “Conservation is so important for this bird species.”

Growing up in the Lodi area, I saw images of Sandhill cranes on local writers’ book jackets and posters for community events. But I never really saw the cranes until this year. They were only a vague concept, one I took for granted.
These ancient birds travel half the world to winter in my hometown, and I hadn’t yet made the 10-minute drive to meet them.
People often look to the distance for wonder and beauty. They scan social media feeds and subscribe to magazines to get away from the banality of everyday life. In the process, they forget to appreciate the value of the nature and history in their own backyards.
At least now I know. Long before “Livable, Lovable Lodi” became “the Zinfandel Capital of the World,” the Sandhill cranes migrated here. It was their home before it was mine.


Written by: Jessica Driver — jmdriver@ucdavis.edu

Disclaimer: The views and opinions expressed by individual columnists belong to the columnists alone and do not necessarily indicate the views and opinions held by The California Aggie.


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