PLEASANTON -- Shielding his face from the freezing rain with one hand and pointing excitedly toward the treetops with his other hand, Rich Cimino exclaimed, "That's a merlin!"

A broad smile lit up the face of fellow bird-watcher Eric Nicholas. The two men turned to each other and high-fived, like two schoolboys who had just conquered their favorite video game. Their rush of triumph was contagious.

A sub-arctic bird that preys on other birds, the merlin rarely makes its way down to the Bay Area. Most bypass the coastline altogether, flying from Canada or another northern point and follow the Mississippi Flyway into Mexico, where they hang out for the winter.

"This is one (sighting) we get excited about," Cimino said. "That's a key bird -- a good find."

Theresa McGovern, who had made her own trek Friday from her hometown of San Francisco to take part in the second annual East Alameda County Christmas bird count, dug her gloved hand in her pocket and yanked out her bird book. She turned the pages frantically, eager to locate the description of what she had just seen.

Anyone who pictures bird lovers as dry, impassive types (think Bert's character from "Sesame Street") hasn't spent enough time with them. For the 90 or so volunteers in Livermore, Pleasanton and Sunol who braved the winter weather Friday to survey their feathered friends -- part of a nationwide effort coordinated by the Audubon Society -- birding is more passion than hobby.

Cimino, who serves as the Ohlone Audubon Society's conservation chairman and the Alameda Creek Alliance's events director, organized the eastern Alameda County count -- now in its second year.

While his group kept watch from Pleasanton's Alviso Adobe Community Park, some 30 other groups were stationed throughout the Livermore-Amador Valley.

Nationally, the Christmas count has been in existence for more than 100 years.

Its purpose is to promote bird conservation and assess long-term trends in winter bird populations -- most recently with an emphasis on how climate change might be affecting migration patterns.

One trend that has been widely reported: grassland birds wintering further north.

Manned by tens of thousands of volunteer birders and scientists armed with binoculars, the counts take place around the country from mid-December to early January.

Audubon and other organizations use the data collected in the wildlife census to assess the health of bird populations overall.

Last year's eastern Alameda County count produced a number of surprises, Cimino said.

Among the birds spotted in the count's inaugural year were a Lewis's woodpecker, which is relatively rare in suburban areas, and five bald eagles.

"That really tells (us) that eastern Alameda County habitat for eagles is in pretty good shape," he added.

Just before the group left Alviso Adobe Community Park Friday, they got another treat: perched in the trees about 10 yards from the street was a wild parrot. Though found in San Francisco and parts of Southern California, the emerald-colored birds are less frequently found in the East Bay.

Between the cold-loving merlin and the sun-loving parrot, there would be plenty to report, Cimino said, grinning at Nicholas.

"Yes!" he exclaimed. "We got two good birds to write up."

Contact Jeanine Benca at 925-847-2125.