Notes about your surroundings.

Christmas Bird Count--While most people spend the holiday season in a whirl of shopping, parties and family gatherings, bird-watchers add one more item to their holiday itinerary--the annual Christmas Bird Count.

On count day, bird-watchers throughout the United States and Canada go out and record every different type of bird they spot. The data compiled during the counts--in most cases organized by Audubon Society chapters--is used to decipher population trends among bird species and provide an early warning if a particular species is declining in number.

The Sea & Sage Chapter of the National Audubon Society will conduct counts on two dates--the northeastern count will be Dec. 16 and the coastal count will be Dec. 30.

Last year, 87 birders participated in the northeastern count and 90 in the coastal count. With 166 bird species counted in the northeastern section and 198 in the coastal section, the Sea & Sage chapter tied for fourth place in North America for the largest number of different birds spotted.

Participants can choose the specific area where they would like to spot birds and how long they would like to stay out. (Most spend the whole day watching for different birds, chapter officials said.)

Areas for the northeastern count are Irvine Park, Irvine Lake, Silverado Canyon, Black Star Canyon, Modjeska Canyon, O’Neill Park and Plano Trabuco, the area near the old Lion Country, the San Diego and Santa Ana freeways junction, Mission Viejo, El Toro and nearby foothills, El Toro Marine Base and nearby foothills, Rattlesnake Reservoir, Siphon Reservoir and nearby foothills, and Peter’s Canyon and Lemon Heights.

Areas for the coastal count are Westminster Memorial Park and the Golden West Street corner of the U.S. Naval Weapons Station in Seal Beach, Huntington Central Park, the Bolsa Chica wetlands, Mile Square Park, the mouth of the Santa Ana River to Ellis Street and the Huntington Beach Pier, Old Santa Ana, newer Santa Ana, Costa Mesa and the west side of the Newport Back Bay area, the east side of the Newport Back Bay area, UC Irvine and the San Joaquin Marsh, and the foothills around UC Irvine and Corona del Mar.

The results of the two counts will be known in early February.

Dinosaurs and Space--The Museum of Natural History and Science’s new site in Aliso Viejo opens Saturday with two major exhibits. “Dinosaurs, Dinosaurs” features 15 robotic, computerized dinosaurs, while “Space: the Infinite Frontier” includes large-scale models of several spacecraft.

Both exhibits run through April 30. Special holiday hours are 10 a.m. to 5 p.m. Monday through Saturday, 1 to 5 p.m. Sunday (closed Christmas and New Year’s Day.) Admission to the museum is $6 for adults and $3 for children. The museum is in the Koll Corporate Center, 150 Columbia, Aliso Viejo.