OUTINGS : Canoe Tours Explore Birds’ Coast Habitat : Upper Newport Bay, on the edge of urban development, is home to a wide variety of species.

Explorers have canoed Upper Newport Bay for centuries. It’s not too late to launch your own adventure into the 752-acre coastal wetlands, former home of a Shoshone tribe displaced by Spanish settlers.

The California Wildlife Campaign operates paddle-your-own-canoe tours of the Upper Newport Bay Ecological Reserve three Saturdays each month. Towering bluffs and cliffs wreathe the bay, populated by up to 30,000 birds seeking out the estuary’s habitats--from freshwater marsh areas dense with bulrush to mud flats packed with tasty clams, shrimp and worms.

Although tiny, the reserve is home to one of the largest clusters of shorebirds found along the Southern California coast. Bring binoculars to heighten your experience.

Should you envision a serene wilderness experience, take note that the bluffs are topped by condominiums, hotels and high-rise office buildings. Rampant urban growth spread to the edge of the wetlands but was halted when the state purchased the area for management by the Department of Fish and Game in 1975.

The result, a sort of freeway-close wilderness, is an eerie reminder of what other natural areas outside city centers could resemble decades hence.

The best months for viewing a wide variety of the 165 bird species recorded--including American avocets, plovers, sandpipers, dowitchers, brown pelicans and peregrine falcons--are August through April when birds winter in the bay.

Begin your two-hour tour by carrying canoes, labeled “The Good Tern,” “Ruddy Duck” and “Pelican Flyer,” to the edge of a wooden dock on Shellmaker Island--one of six islands that provide nesting areas for birds. Should you lack experience with a canoe, a quick lesson by your volunteer naturalist should suffice. Children under 12 years can be seated between two adults.

The tour, consisting of 10 canoes, meanders in and out of marsh areas along the one-mile journey, stopping frequently to take note of six habitats found at the reserve--marine, intertidal, brackish water, freshwater marsh, riparian (near rivers) and upland.

The putty-colored bluffs rising 100 feet at the beginning of your trek are composed of millions of decayed diatoms--hard-shelled microscopic organisms deposited when the area was an ocean bottom. Before 1862, the bay was connected directly to the Pacific Ocean but was severed after the formation of a sand pit, now called the Balboa Peninsula. Fresh water flows in from the San Diego Creek and urban runoff seeps down from the bluffs.

“About one-third of Orange County drains into Newport Bay,” volunteer naturalist and tour leader Jim Cokas said. “We’ve got motor oil, pesticides, antifreeze and golf and tennis balls that wind up here--I even saw a sofa floating by last week.”

The trek sounded less and less appealing, but Cokas reminded the group that the habitat is designed to work overtime to absorb the runoff--although sofas may take time to decompose. (The sofa was spotted in the lower bay, among the world’s largest small-craft harbors.)

“Handling that waste is one of the jobs of an estuary,” Cokas said, maneuvering his canoe toward some cattails to spy on a family of terns. “But here’s the point--just because we’ve drawn lines around this area doesn’t mean it’s protected. Lines tend to be arbitrary. They can’t keep out what you dump down your drain 10 miles away.”

Cokas led the group to an island packed with cordgrass, a favorite nesting spot for the endangered light-footed clapper rail. There are 170 breeding pairs of the large, tawny-breasted bird in the bay, representing 70% of the state’s entire population.

The rail has adapted to the bay’s tides by anchoring nests to cordgrass stems, but with enough slack in the line so their homes can rise and fall with tides. It’s nesting architecture at its finest.

Unusual black skimmers can be spotted in summer months. The skimmer has a severe overbite, a red oversized lower bill tipped in black, that helps it catch fish. The bird, white underneath with a black back, skims the bay, flipping startled fish out of the water as it catches them in midair.

Somersaulting brown pelicans (it’s their way of grabbing some dinner while landing) are also amusing. It’s all stiff competition for Shamu, Sea World’s killer whale.

Winter months bring raptors, red-tailed hawks and turkey vultures soaring among the cliffs. Below, great blue herons and egrets lead a more sedate life.

Don’t forget to listen for songbirds during any month. Although an occasional roaring jetliner drowns them out, the area wouldn’t be complete without its symphony of song sparrows, brown towhees and Anna’s hummingbirds.

Licensed fishing is allowed, with the best spots found off Big Canyon and North Star Beach. Small boats can be launched free at Big Canyon and kayaks can be rented in the area. Boats, including motorized craft, must operate at 5 m.p.h. and below.

WHERE and WHEN

Location: Upper Newport Bay Ecological Reserve, 600 Shellmaker Island, Newport Beach.

Getting there: Travel south on the San Diego Freeway to California 73 south. Within one mile, exit at Jamboree Road and take a right for three miles to Back Bay drive. Turn right on Back Bay and drive one-quarter mile to the reserve’s sign, turning left onto the island.

Hours: 9 to 11 a.m. the second, third and fourth Saturday of each month.

Price: $11 for canoe tour, or $11 annual fee to join California Wildlife Campaign, which includes canoe outing.

Call: (714) 640-6746.