"Some farmers, if they had this concentration of geese, will put out the shotguns and use the sound to distract them," said Brent Tadman, who manages the 9,200-acre (3,700-hectare) Conservation Farms and Ranches on the island.
But birds on Staten Island are allowed to forage in peace, because this is no ordinary farm. Located about 80 miles (130 kilometers) northeast of San Francisco in the Sacramento-San Joaquin Delta, Staten Island was purchased by The Nature Conservancy (TNC) in 2002 in order to create a place where agriculture and conservation can coexist. (Related: "'Walking Wetlands' Help Declining Birds, Boost Crops.")
TNC hopes bird-friendly practices developed and tested on Staten Island will set an example for other farmers for how they can keep their land productive and profitable—while creating habitat for birds traveling along the Pacific Flyway, one of four primary migratory routes in North America.
All About the Cranes
Staten Island is a major stopover and wintering ground for a broad suite of migratory bird species—including waterbirds such as ducks, snow geese, herons, and tundra swans—and shorebirds such as plovers and sandpipers. (See National Geographic's backyard bird identifier.)
It's also one of the most important sanctuaries in the state for sandhill cranes, one of the oldest species of living birds.
"There's a very similar species, if not the ancestral version, of these guys that was around in the dinosaur era," said TNC ecologist Greg Golet.
Two subspecies of sandhill cranes—the greater and the lesser—winter on Staten Island and the neighboring Cosumnes River Preserve. Standing up to 4 feet (1.2 meters) tall, the cranes can be spotted probing for food with their long bills or flapping their way across the farm on wings stretching up to seven feet (two meters) in length. (See more bird pictures.)
"We acquired [Staten Island] largely because of the habitat value it provides for the cranes," Golet said. "That's the main conservation target of the island."
Focusing on the cranes makes sense because the birds are an excellent surrogate, or "umbrella," species, explained Gary Ivey, a research associate with the International Crane Foundation.
"Meeting the needs of cranes supports many other species," said Ivey, who is helping monitor the island's crane population.
Staten Island is one of the few remaining refuges for migrating birds in California's Central Valley, which has seen a 95 percent reduction of wetlands since the mid-1800s.
"The farmlands are critical. If we don't have those in the future, the whole Pacific Flyway could collapse ... If we lost the whole Central Valley, I don't think the birds would jump to another flyway," said TNC's migratory-bird program director Sandi Matsumoto.
Allowing birds to forage uninterrupted on the farm is just one of the wildlife-oriented practices being tested on Staten Island. Waste grain is also left behind postharvest to serve as food sources for the birds throughout the winter.
Additionally, some of the unused fields are flooded with water after harvest so birds can use them as roosting and foraging sites. The depth of flooding in the fields is varied to create a mosaic of habitats for bird species that require different depths. (Watch video: "Flooding Farms on Purpose—For the Birds.")
"A cornfield that's deeply flooded is good for certain species, but not [for] shorebirds or cranes," ecologist Golet explained.
Flooding crop fields creates additional expenses for farmers due to pumping costs, but farmer Tadman said the practice has agricultural benefits as well.
"It also ... [flushes] the fields of salts," he said, "and it helps with weed management, because weeds don't grow under water."
In addition to rice and corn, Staten Island also grows wheat, triticale—a wheat-rye cross—and potatoes. Conservancy scientists are experimenting with varying crop rotations so that the harvest and field flooding can be timed to the arrival of different bird species. (See pictures: "Flooded Fields Bring Back Shorebirds.")
For instance, triticale is planted because it can be harvested in late summer, after which the fields are flooded to provide roost habitat for early arriving migrants.
"This habitat type is in really short supply at this time of year," Golet said.
Win-Win for Birds and Farmers
In some of Staten Island's cornfields, the standing stalks are also flattened after harvesting using mechanized rollers in a technique known as chop-and-roll. (Test your knowledge of the ground beneath your feet.)
"What we saw was that the birds prefer this treatment over just leaving the [stalks standing], probably because they can move around in the fields more easily to forage, and better keep an eye out for predators," Golet said.
Stalks that have been chopped and rolled in the fall also decompose more rapidly, according to Tadman, and can thus be worked back into the soil more readily in the spring without the need for heavy tillage equipment.
Helping birds on Staten Island even extends to the farm's power lines, which have reflective strips attached to twirling pieces of plastic strewn along their lengths to help birds see the lines and prevent collisions.
David Wiedenfeld, a senior conservation scientist with the American Bird Conservancy, said the Staten Island experiment is similar to projects being conducted in other states, including Texas and Louisiana.
Such projects "are a win-win for birds and farmers," said Wiedenfeld, who was not involved in the Staten Island project.
Some critics might say "we need to turn the land back into a wetland and make it completely natural," he said.
"But that's not necessarily better for the birds. This way, birds will use these farms, and farmers can use them as well."
There are signs that TNC's living-laboratory experiment is working. On a recent winter's day at Staten Island, migratory birds are plentiful in the flooded cornfields. Staten has a higher density of birds than most of the surrounding farms, and some species, like the sandhill cranes, return to the same site year after year. (See "Best Bird Pictures: Air, Sea, Ice Shots Win New Contest.")
Equally important, the bird-friendly agricultural practices on Staten Island have not negatively impacted the farm's annual crop yields, Tadman said.
"Even though this farm is owned by The Nature Conservancy, it stands on its own legs and it's required to be sustainable, and we're pretty proud of that fact," he said.
TNC said many Central Valley farmers have expressed interest about Staten Island's bird-friendly practices, but convincing them to adopt similar practices on their own farms can be challenging.
For example, "different farmers have different situations," said TNC's Matsumoto. "One guy's soil could be completely different and the flooding regime would not work, or they don't have the infrastructure to support certain practices."
To help farmers reduce their risks, TNC has teamed up with other conservation groups, including Audubon California, PRBO Conservation Science, and the Natural Resources Conservation Service to provide cash incentives for those willing to implement bird-friendly practices on their farms.
New Crops Bad for Birds
But perhaps the biggest obstacle to widespread adoption of the Staten Island model is not farmers but the consumers who buy their crops.
The rising demand for foods such as grapes, almonds, cherries, olives, and pistachios is tempting many farmers in the Central Valley to abandon rice, wheat, and corn in favor of these more profitable vineyard and orchard crops. (Read "Our Good Earth" in National Geographic magazine.)
"Economically, there's a big push for trees and vines, so you see more of it going in," Tadman said.
That could spell trouble for sandhill cranes and the bird species that fall under their umbrella. "Sandhill cranes, especially, have such large wingspans that they have trouble landing in a vineyard or orchard, and doing so makes them very easy prey" for coyotes and other predators, Tadman said.
To see what effect tree crops can have on migratory birds, one need simply to cross a bridge and drive around farms on neighboring Tyler Island: In fields where pear trees or grape vineyards grow, the birds and the avian chorus present on Staten Island are conspicuously absent.
The Environmentalist Farmer?
But TNC is hopeful that incentives, as well as educating farmers about how a few simple steps can benefit both themselves and birds, will be enough to save the birds that depend on the Central Valley.
Tadman said he doesn't believe farmers and environmentalists are naturally at odds with one another. "I would say we have more common goals than we have differences. It's just sometimes the differences get more of the headlines," he said.
"The best environmentalist in my opinion is your farmer and rancher, because this is how we make a living.
"It's a testament to any farmer or rancher when there's wildlife [on their land], because it's a sign that they're doing something that is working for both humans and wildlife."