Mallards Feel the Heat

Editor's Note: This is the first of three short profiles explaining how the California drought is negatively impacting birds in the area.

The dry, hot summer over in California means bad news for the state's suburbs—the State Water Quality Control Board recently enacted $500 fines for those still watering their lawns. But it's even worse for many water-dwelling bird species. Water levels in local bodies of water have been going down, limiting the birds' habitat, breeding grounds, and food sources. This has resulted in noticeable effects to resident and migratory waterfowl populations, especially the Mallard.

With the males' bright green head feathers and gray flanks, Mallards may be the most familiar duck species in North America. "About 70 percent of the Mallards that winter here are here all year-round," says Greg Yarris from the U.S. Fish and Wildlife Service. As the dominant resident throughout the year, they are the waterfowl species that has been most noticeably affected by the sparse water supply and high temperatures.

"One thing that happened this spring and summer was that [water] deliveries were reduced not just to farmers, but to state and federal refuges," says Yarris. Less water to the refuges means less wetlands and less habitat for waterfowl. "When you have reduced wetland, there is a reduced breeding success," he says. Field researchers have already observed negative effects from the drought for breeding Mallards: Their population has declined 20 percent since 2013, reducing the number of breeding individuals from approximately 298,600 birds down to 238,700.

On top of losing habitat and lower numbers, one of the birds' food sources—rice—is also at risk. In1992, the California government banned the burning of rice stubble and instead recommended that farmers flood their land to let the rice straw decompose. For many years, this was a win-win for waterfowl that could use these artificial wetlands for habitat and for food. But this past fall and winter, less water was sent to flood these dry rice stubble fields, making the space inhospitable to the ducks. It's likely the drought will continue into the upcoming fall, forcing farmers to turn over the soil via plow rather than via flood. This buries the leftover rice grain, creating a two-fold problem—reduced habitat and less food.

This drought has been going on for the past two years already. But this past year has made it clear that conditions are getting noticeably worse for waterfowl in southern California as fall and winter approach. "We just did a modeling exercise on the impacts, on what we anticipate will be available in the wetlands," says Yarris. "We expect at least 25 percent less wetlands."

Experts are especially concerned about what's going to happen when the migratory birds return. "What's going to happen, we fear, is that these [birds] will arrive at these refuges and there will be no water and little food," says Garrison Frost, director of marketing and communications for Audubon California. This could put more stress on resources that are already overwhelmed. Consequently, Audubon California has been lobbying for water deliveries to the refuges this fall.

The group is also doing the best it can to raise awareness for the plight of the waterfowl, lest these Mallards become literal ducks out of water.

Editor's Note: This piece has been modified to emphasize the facts that: Mallards feed on rice grain, not rice stubble; and the rice fields were flooded with less water last year, and are expected to be similarly treated this year.