California’s lingering drought impacts overwintering waterfowlby reducing flooded rice acreage.
By Vicky Boyd
California’s 4-year-old drought not only has meant irrigation curtailments and planting reductions for rice producers, it also has reduced the amount of water available to flood fields after harvest for waterfowl.
Winter-flooded rice fi elds play a signifi cant role in providing habitat for overwintering birds, said Paul Buttner, manager of environmental affairs for the Sacramento-based California Rice Commission. In fact, Northern California rice fi elds provide enough forage for about half of the ducks using the Central Valley during the winter. That doesn’t count the myriad other birds that frequent rice fields.
Food for thought
Depending on the location, rice left after harvest provides up to 60 percent of the food energy for overwintering ducks and geese in the northern Sacramento Valley, said Mark Biddlecomb, director of Ducks Unlimited’s Western Regional Office in Rancho Corcova, Calif. That energy is needed to fuel the long migration north in the spring and to hatch larger egg clutches and tend larger broods.
Although a reduction in winter-flooded acreage won’t cause widespread starvation, it could result in skinnier birds with less energy for the migration north and smaller broods, he said.
“If we continue down this trend of drought after drought after drought, it could become a dire situation,” Biddlecomb said. “We have 4 million to 6 million birds that winter in the Central Valley.”
He said it’s not like the birds can fly to another state for better forage because most of the West also is in a drought.
In 2015, California’s rice producers planted about 410,000 acres, down significantly from the 562,000 acres planted just two seasons before in 2013. During the 2015-16 winter, growers are expected to flood about 100,000 acres, Buttner said. But he stressed those figures are purely an educated guess and are not based on hard data.
The amount of water available for post-harvesting flooding varied by water district. “(The districts) were all affected pretty signifycantly this year, but some more so than others,” Buttner said.
During a normal water year, rice producers in the state typically flood 250,000 to 300,000 acres.
Heading into the 2014-15 winter, waterfowl experts were concerned that the lingering drought would reduce winter-flooded rice fields to about 100,000 acres, concentrating birds and possibly increasing the incidence of diseases, such as avian botulism. But that didn’t happen.
“Certainly, if we didn’t have the wide-scale rain events (in December), the birds would have been more concentrated on fewer acres,” Buttner said. “But the significant rain we had in December kind of bailed us out. It provided large-scale flooding of ground, and the birds were able to expand.”
Those same concerns remain heading into the 2015-16 winter, but the predicted El Niño could change the situation, depending on where in the state heavy rains fall, Biddlecomb said.
“Last year in December, we had some really big storms that helped flood up some fields and alleviate some of the pressure,” he said. “If we don’t get those rains this winter, it’s going to be really tough on the birds.”