Discovering County’s Nest Worth : * 2 guides outline tours for readers, taking them to both popular and lesser-known sites.

Among bird watchers, Orange County is well known--with justification--for its wetlands. Upper Newport Bay, the largest estuary in Southern California, and Bolsa Chica together offer an irresistible attraction to shore birds, gulls, terns and waterfowl.

By extension, of course, that makes these areas irresistible to birders as well. Beginning birders often start here, where birds and species are high in number and relatively easy to see and identify.

But there are other places in the county to see birds, places that may not offer the sometimes spectacular numbers of birds seen in the wetlands reserves, but still boast strengths of their own.

There are several ways to learn of the best birding spots: talk to other birders, take field trips with the local Sea and Sage chapter of the National Audubon Society, or take a simple trial-and-error tour of local parks and wild areas. To help, there are a couple of newly published sources.

The American Birding Assn. has published “A Birder’s Guide to Southern California,” a complete updating of the guide written by the late Jim Lane. Lane, who was born in Orange County, published a popular national series of birding guides before his death in 1987.

Lane’s longtime collaborator, Harold Holt, wrote the new edition, but he is based in Colorado and relied on local birders for assistance. Sylvia Ranney Gallagher, bird information chairwoman for Sea and Sage, wrote the chapter on south Orange County; her husband, Jim Gallagher, took the book’s cover photo.

A number of other county birders, including Brian Daniels, Doug Willick and Gerald Tolman, contributed to the new edition.

The Los Angeles Audubon Society, meanwhile, has published “Where Birders Go in Southern California.” Henry Childs, the author, is a retired biology professor from Upland and an active birder who leads numerous field trips for Los Angeles Audubon. Willick, one of the best-known local birders, is listed as the “correspondent” for the Orange County chapter.

There are similarities between the two books: They outline tours for readers, taking them through the county with stops at the both popular and lesser-known locations, highlighting some of the birds likely to be seen along the way.

The Childs book is organized more easily for ready reference, and in addition to printing simple locater maps, gives a map reference for each location (keyed to the Auto Club of Southern California map of the county). It includes some spots not covered in the Holt book and gives more specific information on such details as parking and entrance fees.

The Holt book is written in a more narrative fashion, although each location is printed in boldface and is indexed. It gives more descriptive information on the sites and more details on the birds that can be found there than the Childs book. Another plus: The checklist in the back of the book includes a graph for each species, showing when and in which habitat it is most likely to be found.

Both can be useful to both beginning and advanced birders. Even for birders who already know the county well, the books can also be helpful in exploring nearby counties. Both cover all of Southern California, and the Holt book includes a section on seeking pelagic (offshore) birds. Neither book, it should be noted, is a field guide.

Here are some of the county locations cited in the books, and what might be found there:

* Balboa and Newport piers, Newport Beach. In winter, when people are scarce, the birds can be plentiful. Some waterfowl that may be seen from the piers: loons (common, Pacific and red-throated), scoters (mostly surf) and grebes (Western and Clark’s).

* Little Corona City Beach, Corona del Mar. Again, when crowds are down, the beach can attract winged visitors: wandering tattler, spotted sandpiper, ruddy and black turnstones, surfbird and sanderling.

* Western edge of Doheny State Beach, Dana Point. The shrubs here sometimes attract vagrant warblers; the first great-crested flycatcher to be seen in Orange County’s was spotted here in 1985.

* Cliff Drive, Laguna Beach. A small island visible from the view point just beyond the Las Brisas restaurant can sport three species of cormorant: Brandt’s, pelagic and double-crested. Other water birds and rocky shore waders can be seen.

* Tucker Wildlife Sanctuary, Modjeska Canyon. Although it is home to many birds of the coastal sage scrub, the sanctuary is best known for its large numbers of hummingbirds. Anna’s hummingbirds can be seen all year, although the peak of the migration for most other species is July and August.

* Carbon Canyon Regional Park, Carbon Canyon. From a nature trail that follows a stream on the southern edge of the park, the sightings in winter can include rare red-breasted and red-naped sapsuckers. Others include cactus wrens and phainopeplas.

* Yorba Regional Park, Yorba Linda. The wintering ducks making use of the man-made lakes here include common mergansers and ruddy ducks. In spring, as many as five different species of swallows can be seen darting above the ponds.

Sylvia Gallagher, in an interview, called Santiago Oaks Regional Park in Orange the most under-appreciated spot for birding. While it has not attracted as many rare and unusual sightings as the better-known Huntington Central Park, “it’s a great place for the regular birds,” Gallagher said. “I can’t think of a better place for people to go.”

It is not uncommon to spot 10 to 15 species before leaving the parking lot. The diverse habitats, including various riparian areas and coastal sage scrub, draw a wide variety of birds to a relatively small area. Among the park’s many permanent residents are black-shouldered kite, California quail, greater road runner and Western bluebird. Winter visitors include red-breasted sapsucker, blue-gray gnatcatcher, hermit thrush and cedar waxwing.

Meanwhile, a good area to spot shore birds, herons, egrets and terns far from the beach is along the Santa Ana River in Anaheim. The trick is knowing where to go. The birds troll the percolating ponds on the river, but the river bottom is constantly being reshaped by bulldozers.

There are several points at which to access the bike trail that follows the river, from Lincoln Avenue to Imperial Highway.

“Where Birders Go in Southern California” by Henry Childs and “A Birder’s Guide to Southern California” by Harold Holt can be purchased through the bookstore operated by the Los Angeles Audubon Society. Information: (213) 876-0202.