Environment

Surging numbers of sandhill cranes on Delta island

Video: Sandhill cranes return to Sacramento-San Joaquin Delta

It's time for the annual return of sandhill cranes to the Central Valley.
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It's time for the annual return of sandhill cranes to the Central Valley.

One of the most majestic autumn rituals in the Sacramento Valley comes with a telltale sound: the distant trumpeting call of approaching sandhill cranes. Their annual migration is an elegant pilgrimage that begins thousands of miles north in Canada and Alaska and brings legions of the graceful birds to the region, where they winter in the Sacramento-San Joaquin Delta, on flooded farm fields and in other marshy habitat.

This year, conservationists once again are recording an unusually large number of cranes on Staten Island, a Delta refuge for sandhill cranes and other sensitive wildlife that is operated by the Nature Conservancy. The number of cranes alighting on the island for their winter roost has been increasing steadily in recent years, according to conservancy scientists. They offer several explanations: The drought has reduced wetlands in the Delta, urban expansion has eaten into crane-friendly habitat, and the broad-scale shift from cropland to vineyards has resulted in less foraging land for the cranes.

The gregarious birds have been migrating to the Sacramento Valley for centuries, starting long before the first settlers arrived in California. They mate for life and stay with their mates year-round.

This year, the first cranes were spotted on Sept. 2, and early October counts found 5,609 cranes roosting at the island, said Greg Golet, a researcher with the Nature Conservancy. During the same week last year, 1,360 cranes were counted. The majority of those counted are lesser sandhill cranes, and about a quarter are greater sandhill cranes.

“Those numbers are what we usually see in early December,” Golet said. “And they’re concentrating just at one site.”

The cranes like to return to the same roosting sites year to year, and their concentrations on Staten Island concern Golet because the island is considered at risk. Sea-level rise or a levee failure would result in saltwater intrusion that would make the land unsuitable for crane habitat. The issue is a looming concern, especially for the greater sandhill crane, a species listed as threatened in California.

“There is definitely a serious risk of catastrophic loss of these historical sites the birds use,” Golet said.

In response, the conservancy is initiating a project that over time seeks to wean the birds from Staten Island and onto less-threatened habitat in the Delta, as well as land farther north in the Sacramento Valley, Golet said.

Cranes are famously loyal to their winter roosting sites, so it won’t be easy to coax them from the island. The conservancy plans to use decoys and playback calls to attract the birds, Golet said. The idea is to create roosting complexes adjacent to agricultural land that is suitable for crane foraging.

Golet said the crane program mirrors the conservancy’s year-old Bird Returns program, which so far has established 30,000 acres of wetlands in the Sacramento Valley to benefit migrating birds. In that effort, the conservancy rents acreage from rice farmers to provide habitat for migrating waterfowl.

“We pay them for the pumping costs, and we also pay them for the cost of mulching,” Golet said.

In return, the conservancy dictates how large an area to flood, how much land to keep dry and the timing of the flooding. That same paradigm will be used in its crane habitat program.

There are some signs that the cranes may already be making the move north, said Kurt Richter, who farms rice near Colusa.

“We have seen tons of cranes this year, more than I’ve seen ever,” Richter said. “We usually see two or three sandhill cranes on the farm, but this year there we’re seeing at least 70 cranes in the fields every day.”

Richter has agreed to participate in the conservancy’s crane program, and in early November will flood 55 of his 229 acres to create crane habitat. He plans to use groundwater to flood land that he fallowed this year because of the drought.

Under their agreement, the conservancy will pay Richter to keep the land flooded until late January. It will take at least 4 inches of water to make suitable roosting habitat. The conservancy also will pay Richter to leave 174 acres of rice straw in place so cranes can forage nearby.

Neither the conservancy nor Richter disclosed the payment amount, but the crane program as a whole in the region costs $50,000. “This is not a moneymaker for us,” Richter said. He described his enthusiasm for the project as altruistic in nature.

“Wildlife has used this part of the Valley as habitat and nesting ground for thousands of years. We’ve been farming it for rice for maybe a hundred years,” Richter said. “We’re not so greedy as to think that all the water is here just for us.”

For now, the birds are viewed best at dawn when they take off, or dusk when they return to their roosting sites. Ideal viewing sites can be found on Staten Island and the Cosumnes River Preserve.

Edward Ortiz: 916-321-1071, @edwardortiz

19th Annual Lodi sandhill Crane Festival

What: The annual festival offers speakers, workshops, art shows and more than 50 tours relating to sandhill cranes. Tours range from crane fly-ins to a Delta birding cruise, and can be accessed by foot, kayak, bus, car or canoe.

When: Nov. 6-8

Where: Hutchins Street Square, 125 S. Hutchins St., Lodi

Cost: $5-$45

Information: 800-581-6150, or online at www.cranefestival.org

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