Ever wonder why you’re seeing more (or fewer) of a certain kind of bird around your neighborhood than you used to? Now you can help scientists figure out what’s going on, as part of the 15th annual Great Backyard Bird Count cosponsored by the Audubon Society (tomorrow through February 20). The public’s participation nationwide in simply counting the kinds of birds we see and submitting the tally helps researchers assess how this year’s winter has affected bird populations, track migratory patterns, and more. This Saturday, there’s a free workshop in Oakland’s Rotary Nature Center (10 a.m., 600 Bellevue Ave., 510-238-3739), on the edge of the Lake Merritt bird sanctuary, as part of the effort, where you’ll learn how to identify birds and more details about the project. After the Great Backyard Bird Count is over, click here to check out the results.