* YARD BIRDS: The sixth annual Great Backyard Bird Count will run from Friday to Feb. 17. Sponsored by the National Audubon Society and Cornell Lab of Ornithology, the nationwide census depends upon information gathered by volunteers (from novice watchers to experts) to better monitor the numbers within and health of bird populations, especially those hit hard by the West Nile virus and loss of habitat through development. To participate, visit www.birdsource.org, which contains information focusing on identification, data entry and conservation topics. It costs nothing to take part in the count, just an awareness of what is going on in your yard and nearby park.

* KEEP ON TURNING: Winter isn't the high season for biking but it is a good time to acquire or sharpen your fix-it skills. Allen Muchnick, a League of American Bicyclists certified instructor, will teach two maintenance classes in the upcoming weeks at Pimmit Hills Center in Fairfax County. The first, starting at 6:30 p.m. on Tuesday, will include a talk on proper fitting, breakdown repairs and inspection; you don't have to bring your bicycle. The second, on Feb. 26, will be a hands-on clinic and bikes and tools are required. Each class is three hours and costs $45 ($35 for Fairfax County residents). Call 703-227-2377 or e-mail muchnick@capaccess.org for more information.

* GET WITH IT: The Northern Virginia Hiking Club and Potomac Appalachian Trail Club will host a 17-mile circuit hike from Woodstock Gap to the Strasburg reservoir on the Massanutten and Tuscorara trails next Saturday. Departure time is 7:30 a.m. at Oakton Shopping Center. Trip is open to the public. Call Jack Thorsen at 703-339-6716 or William Needham at 410-884-9127 for details.

-- John Mullen

mullenj@washpost.com