Environment : Notes about your surroundings.

SANDERLINGS: County residents who frequent sandy beaches can help out with a research project on sanderlings--a small, plump species of sandpiper that is commonly seen running in and out with the breaking waves.

As part of a research project on shorebird migration and wintering behavior, juvenile sanderlings have been color-banded and released at several sites in the state. Help is needed in keeping track of the whereabouts of these birds.

Each bird carries a green or white band and one other band on the left leg, and from one to three bands on the right leg. Colors include red, white, green, yellow and orange. Should you sight a banded bird, please report the location, date, time and band combination to: Barbara Kus, department of biology, San Diego State University, San Diego, Calif. 92182. The telephone number is (619) 594-4357.

If you are interested in surveying a particular beach on a regular basis (weekly or monthly) or even on an irregular basis, contact Kus for more information. EVENTS: The Los Angeles Mycological Society will hold a wild mushroom fair today at the Museum of Natural History and Science in Newport Beach from 10 a.m. to 5 p.m. The fair features demonstrations, displays and lectures on common Southern California fungi. Admission is $2, free for children 12 and under. Information: (714) 640-7121.

The South Coast YMCA will hold a nature walk at Mason Park in Irvine at 10 a.m. Friday. Call (714) 859-3496 for information. Oak Canyon Nature Center in Anaheim Hills will hold a nature film festival at 10 a.m. Saturday. Information: (714) 998-8380.