As we move into March, we will see several changes in the Yolo Bypass Wildlife Area. Spring is the time for seasonal wetlands to be drawn down; so many ponds will become mudflats and then dry up completely. This change promotes the germination of moist-soil plants that produce a high seed load. The seed is an important source of food for fall migratory waterfowl. Some water will be held in a few specific ponds through the spring for our Discover the Flyway school programs as well as for ducklings.
It is likely that the dam at parking lot G, also known as the Los Rios Check Dam, will be put in place early due to expected drought conditions. This dam is removed in the fall to allow water to flow for salmon, but is needed to help store water though the summer for agriculture and flooding of wetlands. In the southern portion of the Wildlife Area, pastures are irrigated with the help of this water. Currently thousands of geese are eating on the greens to gain the needed nutrients for their migration back north.
Last fall, right after the rice harvest, heavy rains came. Because of the sudden flooding of the fields, fall work, such as discing rice stubble, was not completed. Tractors will be working the fields as soon as they are dry, to prepare for spring planting. Watch for shorebirds as the rice fields dry.
California Department of Fish and Wildlife (CDFW) staff are busy mowing roads and trails. They also hope to disc tule from some of the seasonal ponds to open up areas that have grown thick. Since the Wildlife Area is managed and fire no longer naturally occurs in the wetlands, as would have happened historically, the tule and cattail growth can overrun the ponds making areas too thick with plant life. This causes issues for the waterfowl as well as increases potential for mosquitos, since the mosquito fish can’t get in there either.
Over the years, the 25-acre Green’s Lake has filled with sediment. As part of the Yolo Bypass Wildlife Area Habitat & Drainage Improvement Project this summer, Ducks Unlimited will deepen portions of the lake. This work cannot begin until May to prevent disturbance to the Giant Garter Snake, which is a State and Federally listed threatened species. The modifications will help both the farmer and CDFW control water flows. An added benefit is that the road on the east side of Green’s Lake will be raised which will create a better road to the viewing location used for our Bat Talk and Walk programs. For this summer, we will need to use a different route.
Every season brings changes to the wetlands. We hope you visit and enjoy this gem.
March 1, 2022