"This business of owling is done more by ear than by eye. Each species has a distinctive voice. The Western screech owl is a misnomer. It doesn't screech. It has more of a soft whoo whoo whoohoohoohoo hoo, and it can bark like a dog," said Harwood, the director of education at Hidden Villa in Los Altos Hills.
A self-described owl enthusiast, Harwood is one of thousands of people who will flock to field, woods and wetlands Dec. 16 in an annual tradition, the National Audubon Society Christmas Bird Count. Birders brave the sleet, snow, rain and cold to tally birds. The count helps identify trends among the flighty species, so that scientists and ecologists can better understand the state of bird populations and how habitats need to be protected or restored to help species thrive — or even survive.
A 15-mile-diameter Palo Alto "count circle" covers land from roughly Canada College in the northwest to the ponds in Sunnyvale to the southeast, from Ravenswood Point near Dumbarton Bridge in the north to Upper Stevens Creek County Park in the south. The circle is divided into eight separate regions in which birders do their scoping and tallying.
The Christmas Bird Count is in its 114th year. It was born out of a very different American tradition, according to the National Audubon Society. Prior to the turn of the 20th century, hunters participated in the Christmas "Side Hunt." Whoever brought back the biggest pile of feathered and furred quarry won.
But scientists were concerned about declining populations of bird and wildlife. The problem of disappearing species was so noticeable that Stanford University became a California state game refuge by state legislation in 1927, after a university zoologist and the Zoology Club spent the early part of the century pushing to ban hunting and other activities harmful to animals in its open spaces.
On Christmas Day, 1900, ornithologist Frank Chapman, an Audubon Society officer, proposed a new holiday tradition, a "Christmas bird census" that would count birds instead of bagging them. During the first count, 27 participants found about 18,500 individual birds and 89 species in 25 locales from New Brunswick, Canada, to Louisiana. Birders in Pacific Grove, Calif., were the state's only participants that first year, according to Audubon.
Last year, more than 71,500 participants throughout the Western Hemisphere counted more than 64 million birds and tallied 2,296 species in the annual count.
Birds are an attractive hobby, said Mike Rogers, who has been birding for 30 years. He takes part not only in the Palo Alto circle count, but in others in Santa Clara County, including in San Jose and Mt. Hamilton. The counting circles are organized so they don't overlap.
"It's a neat hobby. You can do it anywhere, and it doesn't cost a lot of money," he said.
He paused, revising that last statement. People start out with a pair of binoculars, but they often graduate to bigger and more powerful spotting scopes and cameras.
"You get bitten by the bug," he said.
Photographer Tom Grey, whose bird photos are featured in this article, is a retired Stanford University law professor. Birding has become a bigger and bigger passion, and over time he has bought increasingly sophisticated and costly equipment, he said. Grey has photographed 491 species in North America and 144 elsewhere.
It's not just the thrill of the hunt, birders said. Discovering new species in an area can sometimes portend a trend, and the counts help land managers understand the condition of their habitats from a bird's-eye view.
"In 1967-68, the first Nuttall's woodpecker was found at Foothill College. They were found earlier in the Mt. Hamilton range but not here. Now they are common," said author Ruth Troeschler, who has a master's degree in biological science. She has been part of the bird count since 1967.
The presence of certain bird species in the Bay Area has changed in part because of shifts in the environment.
"Robins were only found in the Sierras in the summer. But as people planted lawns, they stayed here. They like grassy meadows," Troeschler said.
As people have planted conifers in the flatlands, birds that enjoy high perches have made their homes here.
"There didn't used to be conifers here. That's why El Palo Alto is so noteworthy," she said.
The count also keeps track of declining species. In the 1980s, the Christmas bird count found a decline in the American black ducks that wintered locally. Conservation efforts were put in place to reduce hunting of the species, according to the Audubon Society.
In 2007, bird-count information showed that some of the country's best loved birds have taken a nosedive in the past 40 years.
Locally, the burrowing owl used to be found all throughout the flatlands around the San Francisco Bay and to the south in the 1960s, but now it only lives around the edge of the bay and in a few other places, Troeschler said. In some cities, such as Mountain View, open areas such as golf courses and landfills are now being managed to support burrowing owl habitats.
But a more obvious example of how environmental change can help or hinder new species is present in most Bay Area neighborhoods.
Looking out her window, Troeschler watched the crows come to eat the persimmons on a back-yard tree. She always leaves some of the juicy orange fruit at the top for the birds, she said. Crows have become ubiquitous as more people — and landfills — have populated Silicon Valley, she added.
Some municipal changes are helping the birds. Cities are planting more Chinese pistache trees as part of their urban landscaping. It turns out the berries are attractive to birds such as the Western bluebird and some eastern bird species, which last year stayed well into spring, she said.
Troeschler has coordinated the urban bird count in Palo Alto's Region 4, which runs from San Francisquito Creek in Palo Alto to Sunnyvale and from U.S. Highway 101 to Junipero Serra Boulevard/Foothill Expressway. The birders can count and identify species in their own yards with a pair of binoculars.
Trying to note the number of birds in flight in an open field or marshland presents its own special concerns. Jack Cole, Palo Alto count-circle coordinator, said he tallies the number of birds in a 1-foot square and then multiplies that number by the estimated number of square feet of the flock.
An exact number is a guess.
Birds are transitory, and counters record the genus and species of birds, the direction they are flying, time of day, height of the tide, and any distinguishing characteristics of an individual bird that could help weed out double counts as the birds fly through other regions, he said.
On the day of the count, Cole will arrive at Region 1, mostly baylands region where elusive and endangered clapper rails hide in the pickleweed.
Cole looks for rare birds, noting "vagrants" that might have flown off-track during migration.
"We count everything we hear or see. This is such a big migratory area. Hundreds of thousands of birds winter here," he said.
Cole will arrive in the baylands at 8 a.m., one hour after the low tide, and he'll stay throughout the day. Different species ebb and flow with the tide. Sandpipers peck for invertebrates in mud flats; avocets wade in the lagoons for crustaceans and insects; and ducks glide across the deep, cold winter water. Secretive sparrows and rails emerge from the grasses and reeds during high tide, escaping the rising water.
"When I first started birding, I could see a Western tanager," he said, of the strikingly colorful yellow, black and white bird with a scarlet head. It has become rare over the years.
He listens for the shrill call of cedar waxwings.
"I hear them before I see them," he said.
Nearby, a graceful snowy egret stood on a single stilt-like leg in a pond near the Ravenswood Open Space Preserve in East Palo Alto on a sunny afternoon.
Cole pointed to a row of electrical high-voltage towers.
"Peregrine falcons perch up there," he said.
The rarest bird he has seen during the count was an eastern sparrow, the Nelson's sparrow, found at Dumbarton Point near the railroad trestle, he said.
October came in like gangbusters, with nine new species sighted in Santa Clara County instead of the usual four or five, Bill Bousman noted in a blog through the South Bay Birders Unlimited.
That could be promising news for birders during this year's count.
Rogers said the Christmas Bird Count offers new and seasoned birders a chance to see some rare species. He is the Region 2 coordinator, which encompasses the Palo Alto Baylands and Moffett Field in Mountain View.
A bar-tailed godwit — a Siberian species that also breeds in western Alaska — was spotted this year for only the third time in Santa Clara County, he said.
At the "countdown dinner" held at the end of the count day, people "ooh" and "aah" as the rare species found are announced, Rogers said.
Birders will have another chance to glimpse the unusual species and add to their spotting lists during the Jan. 4 "County Chase." The half-day event attempts to track down some of the unusual birds seen on the Christmas Bird Count.
But there are always species that elude the counters, regardless of how carefully they look, Rogers said.
"There is one that still stings. At San Francisquito Creek near Highway 101, there was a Cape May warbler near a eucalyptus tree. It was found three weeks after the count. Undoubtedly, it was probably present at that time, but it was missed," he said.