Birders Take Cause Under Their Wing : Nature: A census of fowl near Sepulveda Dam will be used to help persuade legislators to establish a Los Angeles River park.

The blue grosbeak flew into a willow tree and half a dozen bird watchers were all atwitter.

The violet-blue male grosbeak is only about the size of a fist, but to bird watchers, it was a big deal.

“That’s the bird of the month,” gushed Dan Cooper as he led fellow birders through the Sepulveda Dam Recreation Area early Saturday morning. “They only migrate through for a short time and they’re quite rare.”

As far as Cooper and his companions were concerned, the rarer the better. Cooper was leading a special mission aimed at protecting the Los Angeles River by documenting the fowl that flock to its banks.

The “bird-a-thon,” sponsored by Friends of the Los Angeles River, began promptly at 8 a.m. when eight sleepy-eyed bird-watchers began forging through the thick brush along the river near Burbank Boulevard. It was the group’s first bird census in the Valley. After an hour of counting and faithfully recording their tallies in notebooks, the group visited three other sites downriver, ending the day in Long Beach.

The grosbeak was one of 300 birds representing 45 species spotted in the Sepulveda Dam Recreation Area. Each find was usually accompanied by excited commentary.

“Check out the egrets!” one birder said, pointing at four white birds soaring overhead.

“Yeah, they’re snowies,” Cooper said, jotting down the sighting in a green notebook.

“Is that a heron?” someone asked, pointing at a large bird.

“A green-backed,” Andrew Federonich replied, nodding affirmatively.

Federonich, a 44-year-old veteran birder who lives a 10-minute walk from Sepulveda Dam, regularly counts birds there for the San Fernando Valley chapter of the Audubon Society. He said about 200 species of birds live near or visit the river.

Cooper and his companions plan to use their data to prod legislators into preserving the river and other waterways near Sepulveda Dam. They also would like to see the entire 58-mile river transformed into a park.

Cooper, a birder for 12 of his 17 years, spotted the sparrows and warblers swiftly, pointing and shouting out their names in quick succession. Two novice birders worked hard to keep up.

“When you’re just walking along, they all look like little brown birds, but through binoculars you can see all the markings and you realize their beauty,” said James Howald, 37, of Atwater, who shared a set of binoculars with his wife, Jackie Burhans.

“The funny thing about birding is when you think you see something, and it turns out to be a leaf or a branch,” Burhans, 29, confessed.

In her zeal, Burhans has sometimes sighted strange giant birds which more experienced colleagues dubbed “Piper Cub warblers.” Her giant birds were airplanes.