Making a Crane Marsh


In the California delta, sandhill cranes have been losing habitat to agriculture and urban sprawl. Now, they’re finding opportunity on wildlife friendly farms.

A chorus calls out from the water. A rattling, almost gravelly, bugle — what Aldo Leopold called a “trumpet in the orchestra of evolution.” It’s the unmistakable sound of thousands of greater and lesser sandhill cranes chattering in their wetland roost.

The sun starts to rise over the California delta, coloring the water a deep, early-morning purple. The cranes fly to neighboring farmland by tens to spend the day foraging and dancing in pairs. “They’re just fun to watch,” says Emily Wells, a conservation program manager at the Nature Conservancy, from the edge of the wetland. “The way they dance and move. You can start to learn from their movements what they’re going to do next.”

On cue, a crane throws up a tuft of grass. Another hops and spreads its wings, a not-too-flashy display of reddish-gray feathers against the pale morning light. Again from Leopold: “A new day has begun on the crane marsh.”

These sandhill cranes are roosting in fallow farmland that has been purposely flooded for waterbird habitat on Staten Island. Not the New York borough, but a leveed island in the Sacramento-San Joaquin Delta along the western edge of California’s ag-heavy Central Valley. Thirty miles south of Sacramento and surrounded by two forks of the Mokelumne River, Staten Island looks like many other islands in the delta: a checkerboard of farm parcels, with a hard-line leveed boundary separating farmland from the water. In fact the island is more like a large bowl floating in place — beyond the levee, the water’s surface sits 30 feet higher than the land inside.

The Nature Conservancy purchased the 9,000-plus acres of farmland on Staten Island in 2001 with three primary goals in mind. On one hand, it was an act of preservation. The Central Valley serves as the southern terminus for many migratory birds. The greater sandhill cranes breed in northeast California and eastern Oregon, the lesser sandhill cranes as far north as Alaska and even eastern Siberia, before they start showing up in the delta in September for winter roosting and foraging. The Nature Conservancy acquired Staten Island as a key link in that flyway.

The second goal is to continue the agricultural production of the land. On Staten Island, the Nature Conservancy team grows alfalfa, triticale, potatoes, rice, and corn. They also run cattle on irrigated pastures.

In other words, Staten Island is working land, a place to demonstrate how these crops can be grown in a way that doesn’t negate wildlife conservation. Certain fields are left fallow in rotation. They are then flooded to allow for temporary wetlands, adjacent to productive fields. “Corn, triticale, rice. They’ve all been shown to be compatible with wildlife,” says Wells. “We’re an example of how to make it work.”

Lastly, the Nature Conservancy hires avian monitoring technicians to conduct wildlife surveys. As the cranes usher in a new day with their rattling call, Wells, a former technician now managing the team of surveyors, sets up a surveying scope on the edge of a flooded field to make her count. According to Wells, it’s unclear exactly how many cranes make it to the Central Valley each winter, but on this day in late November, when the number of roosting cranes usually peaks for the season, she expects to count close to 5,000. Some years, when drier winters send cranes to Staten Island for the provided wetlands, that number can double.

In the 1940s, there were five breeding pairs of greater sandhill cranes in California, according to the Audubon Society, so these numbers on Staten Island alone show a significant recovery. Still, today’s population is still a fraction of historical numbers. Before the Gold Rush brought its stampede of settlers touting the flag of manifest destiny, the Sacramento-San Joaquin Delta was a 1,100-square-mile salt marsh, abundant in migratory birds and waterfowl, tule elk, salmon, smelt, and marine mammals like beavers and otters. It was also home to an Indigenous population of about 300,000 people.

But in the twentieth century, much of this landscape was drained and diked for agriculture and urban sprawl. Developers replaced dynamic wetlands with the neat geometry of farmland, levees, and aqueducts we see today. The delta also became the heart of California’s water supply as the state population grew. The delta had enough water while much of California had too little, developers decided, so the state and federal governments built pumping stations to deliver delta water to coastal cities like San Francisco and the agricultural industry throughout the rest of the Central Valley. Today, 25 million people get their drinking water from the delta, while industrial-scale agriculture, the state’s economic stronghold, depends on this water to produce two-thirds of the country’s fruits and nuts and a third of its vegetables.

The delta is a prime example of an ecosystem and its wildlife caught in the crosshairs of economic growth. Some say it’s the prime example. Chris Austin, curator behind the extensive California water blog Maven’s Notebook, called California “the most hydrologically-altered landmass on the planet.” In such a human-altered landscape, conservation hinges on how we view the delta as a place: Is it an ecosystem with inherent value or a source of natural resources?

The Nature Conservancy sees it as both. Aligned with the mission of the Nature Conservancy as a whole, which is to promote conservation on both working lands as well as through refuges and protected land, the Staten Island team is working to inject conservation values within the system of cash-crop farming that now defines the region.

A large portion of the nonprofit’s farm is committed to growing corn for animal feed, for instance. And according to Wells, they plant both GMO and non-GMO varieties, despite controversies over the lingering environmental and systemic issues surrounding both genetically modified crops and growing food to feed livestock. Evidently, the Nature Conservancy isn’t using Staten Island to completely disrupt the system of agriculture in place in the Central Valley. The team makes market-based decisions — as any neighboring farmer might — on which corn variety to use based on various factors. Non-GMO corn can be sold for a higher price than genetically modified varieties, for example, but is more susceptible to disease.

Of course, the motive here is economic, to fund the farm and further conservation efforts, but sandhill cranes forage in these fields all the same. They’re opportunistic feeders, scavenging the cornfields for invertebrates and “anything they can get their beaks on,” as Wells puts it, as long as there’s flooded roosting habitat nearby. This year, the Nature Conservancy flooded around 1,500 acres on Staten Island. In the spring, once the birds fly north, much of that land will be put back to agriculture.

The idea is to make this sort of wildlife friendly farm replicable elsewhere in the delta. As part of that vision, the Nature Conservancy has a program called BirdReturns, in which staff identify farmland that would ideally be flooded for migratory birds. The group then “rents” that land from farmers for the duration of the birds’ stay, making it profitable for farmers even when it’s fallow. Audubon California has a similar program called the Working Lands Program, which depends on partnerships with landowners along the cranes’ flyway.

But conservation within a large-scale agriculture system often competes with the market trends. “One of the biggest threats sandhill cranes face here is loss of foraging habitat,” says Wells, who has noticed an increase in vineyards and olive orchards in the delta as market values favor those crops. “These orchards don’t provide good habitat for water birds. There are ways to make them more compatible, but that would affect these farmers’ bottom line.”

Delta agriculture abides by the rules of economics after all. Aldo Leopold lamented these limits to conservation in his crane-inspired essay “Marshland Elegy,” where he wrote that “the ultimate value in these marshes is wildness, and the crane is wildness incarnate.” What the crane really needs, said Leopold, is a wild, roadless marsh. Anything else is mere imitation. This is especially true when considering the role wetlands play in mitigating climate change, from buffering storm surge to sequestering carbon.

But environmental historian William Cronon warns against a dualistic view of wilderness as a place where man does not belong: “The dream of an unworked natural landscape is very much the fantasy of people who have never themselves had to work the land to make a living,” he wrote. Wildlife, especially birds, don’t know the borders between wildlife refuge and working land. They look only for opportunity. And in the absence of wilderness, Staten Island is at least a reminder of what the delta once was, as well as what it could be.

As Wells scans the horizon, she jots the number of cranes she sees for her weekly count. But cranes aren’t the only birds she spots. In the course of a morning survey, Wells also sees a pair of tundra swans, a few sandpipers, black-necked stilts, meadowlarks, red-winged blackbirds, hooded mergansers, canvasback ducks, and thousands of cackling geese. She also points out three coyotes trotting across a cornfield, as well as a sea lion bobbing in the Mokelumne, hunting striped bass.

“We also had a juvenile bald eagle here yesterday,” she says from behind her scope, “so keep your eye out.”

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