Notes about your surroundings.

MERLIN: One rare winter visitor to Orange County is the merlin, a falcon that breeds at high latitudes through the northern hemisphere and usually winters north of Southern California.

Once known as the pigeon hawk, the merlin feeds on small birds. In a typical winter, only two or three merlins are spotted in Orange County. “That’s a pretty rare bird,” said Doug Willick, who compiles a list of rare bird sightings in the county for American Bird magazine. “It’s a fairly rare winter visitor.”

Willick recalled three sightings in the county so far this winter before this week, when one of the birds was found critically injured, victim of a shooting. It is one of a rash of unexplained shootings of birds of prey--30 dead or injured birds have been found so far this year.

Other victims of the shootings have included sharp-shinned hawks, Cooper’s hawks, red-tailed hawks, red-shouldered hawks, American kestrals, barn owls and a great-horned owl. The 30 known shootings in the county matches the total for all of 1988. Many have been found in business or commercial areas, apparently shot from automobiles.

FAREWELL TOURS: Saturday marks the last public walking tours of the season offered by Amigos de Bolsa Chica and Friends of Newport Bay.

At Bolsa Chica and Upper Newport Bay, volunteers will be stationed at various points along the tour to describe the wildlife, geology, human history and current status of the wetland reserves. Both areas are vital wintering grounds for many migratory birds.

At both locations, the free tours leave every 15 to 20 minutes from 9 to 10:30 a.m. Tours last about 1 1/2 hours. Wear comfortable shoes, and a hat if the sun is out. Binoculars and a bird identification guide are recommended.

The Bolsa Chica tours leave from the ecological reserve parking lot on Pacific Coast Highway, across from the entrance to Bolsa Chica State Beach between Warner Avenue and Beach Boulevard.

FAMILY TRIP: The Santa Ana Zoo is offering a family field trip to the Santa Rosa Plateau in Riverside County, an area of wildflowers and oaks, on March 25. Zoo staff will lead participants on an easy-paced, 4-mile hike through the wildlife-rich area. The plateau is home to five endangered species and several rare plant communities, including vernal pools and southern oak savanna.

Tuition per parent/child pair is $25 and includes field instruction, materials and transportation. Space is limited. For reservations, call Jennifer Rigby, (714) 836-4000.