Grains of Change
In California's Central Valley, where a quarter of the food varieties we eat are farmed, a new generation of growers is teaming up with conservationists to make sure that rice and long-billed curlews will always mix.
Herein lies a problem. The estimate of 20,000 curlews in North America was based in part on the annual continent-wide Breeding Bird Survey, a census conducted in June when most species are easily heard or seen as they defend their territories and engage in courtship displays. By then, however, long-billed curlews--courtship and breeding far behind them--are slipping inconspicuously through the grasslands with their chicks.
With this in mind, in 2004 and 2005, several scientists set up surveys across 16 states, looking specifically for curlews in March and April, when the birds would be more visible. Although their sample size was small, through mathematical extrapolation they came up with a new estimate--100,000 to 160,000 long-bills. This, surely, is good news.
Gary Page, director of the Point Reyes Bird Observatory Conservation Science's (PRBO) wetlands ecology division and one of the country's leading shorebird experts, took an interest. "I wanted to see if we could document the importance of the Central Valley to the curlews," he says, "so we needed to know how many curlews depend on the valley and what kind of habitat they are using." The question was whether surveys could be done without having to gain access to private property, so in 2007, 2008, and 2009 Page drove public roads in and around some of the area's agricultural fields and pastures. He discovered that with a spotting scope he could see the big, unmistakable curlews even in the fields' far corners.
Page, David Shuford, a senior biologist with the PRBO, and Langham then coordinated volunteers to conduct daylong surveys that would cover much of the Central Valley and all the interior valleys of California. From September 2007 to August 2009 more than 100 people participated in four surveys. The results suggested that the new estimate of more than 100,000 curlews was likely more accurate than the old one of 20,000 birds. In fact, most of the surveys tallied 18,000 to 20,000 curlews in one day--just in the Central Valley.
Many birds were spotted in the shallow waters of rice fields. In February 2009 Audubon California, the PRBO, The Nature Conservancy, and the California Rice Commission sponsored a workshop for rice growers to discuss ways to make their fields even more hospitable to long-billed curlews and waterbirds in general. "We weren't really sure how it was going to go, but there was an excellent turnout," says Langham. "The rice growers really wanted the science to show how the birds were using their lands. If we could just show them the right things to do, they were very willing to consider them." Don Traynham was among six growers to volunteer for a pilot project. Traynham, outgoing and energetic, works 1,500 acres of rice fields in the northern Sacramento Valley.
In California rice is harvested once a year. Each April the fields are flooded with five inches of water, and the rice seed is planted. During the growing season, May to July or August, more water is added, but before the season's apex, in August and September, the fields are dried out so the heavy harvesters can do their work. The rice stalks that remain after harvest must be worked back into the soil over the winter in order to prepare the fields for replanting the following spring.
For 80 years, since rice farming began in California in 1912, the growers routinely set their fields ablaze, burning off the straw. This was efficient, though unpleasant to anyone who lived nearby. "I grew up in Sacramento," Langham says, "and as a kid you couldn't play outside for two weeks or more. It was hard to see. Ash fell from the sky." In 1991 the Rice Straw Burning Reduction Act mandated that burning be phased out over the next decade. As rice growers tried various mechanical means to get rid of the straw, some realized that keeping water in the fields created anaerobic conditions that would break down the plants naturally. "Lo and behold," says Langham, "this also had the effect of creating a huge amount of waterbird habitat."
Discussions at the workshop focused on finding ways to more closely align farming practices--primarily when and how much water is kept in the fields--with migrating and wintering waterbirds' seasonal cycles. Practices that would provide more water for the curlews and waterfowl ranged from simply holding rainwater in the fields after the summer harvest to extending how long the water was retained during the winter. Traynham, who was already managing land around his rice fields for wildlife, agreed to try one of the more labor-intensive suggestions: create islands in the fields that could serve as nesting areas for black-necked stilts and avocets as well as other birds. Talking about these projects, he acknowledges that historically farmers and conservationists haven't always seen eye to eye. "Yeah, it used to be that way," he says. "But with time you can change anything. Pro-environment is where it's at, and if you're going to survive, you better be part of it. With the political environment we live in today, coalition building is the only way you get anything done."