Notes about your surroundings.

Bolsa Bash--The 15th annual Bolsa Bash, sponsored by the Amigos de Bolsa Chica, is planned for Saturday at the Huntington Beach Civic Center. The theme of this year’s event is “Routes,” referring to the migratory routes followed by the many birds that visit the Bolsa Chica wetlands.

The party will feature a buffet of international fare representing the various countries also visited by the wetland’s feathered visitors, as well as a live band, dancing, a silent auction and door prizes. People are asked to come in international costumes to complete the theme.

Reservations are required. Admission is $20 per person.

The event begins at 7:30 p.m. For more information, contact the Amigos de Bolsa Chica office at (714) 897-7003.

Marsh Trip--The Sea & Sage chapter of the National Audubon Society will host a field trip to UC Irvine’s San Joaquin Marsh on Saturday. The 200-acre reserve is not generally open to the public, but gates will be unlocked at 7:30 a.m. for those participating in the field trip, with no admittance after 7:45 a.m. The group will stay at the marsh until noon. Contact trip leader Dick Kust at (714) 896-8878 for more information.

Mountain Lions--”Tracking Mountain Lions in Orange County,” a slide lecture by wildlife biologist Paul Beier, will be presented in Brea on Friday. Sponsored by the Youth Science Center, the 7:30 p.m. program is at the Hartley Auditorium at the Unocal plant, 376 S. Valencia Ave. Admission is $4 for adults and $1 for children. For more information, contact Laura Cohen at (714) 525-0831 or John De Herrera at (714) 773-8338.