To most people, a long stretch of fenced-off beach in the Oceano Dunes State Vehicular Recreation Area looks like a windblown, barren desert.
To the trained eye of Cheryl Lish, it's a hive of avian activity.
Today, the least terns are on display. Through a spotting scope, Lish watches as a downy tern chick greets an adult in hopes of being fed a fish. Another tern flits by with a small fish in its beak.
Lish looks up from the scope when she hears a series of high, sharp calls, and she watches a pair of acrobatic terns harass a gull that's gotten too close to the nesting area.
"I do a lot of birding by ear," the 20-year bird watching veteran said.
All of this is happening as dozens of helmeted quad riders zoom by just yards away, some of them giving Lish and her spotting scope quizzical stares.
Lish, an Arroyo Grande resident, is part of a team of a dozen monitors with the state Parks Department who continuously keep watch over a 300-acre seasonal shorebird nesting area within the park. Nearly 100 snowy plovers and about half as many terns annually nest in the park.
Aside from a population in the Point Reyes National Seashore, the plovers and terns at Oceano Dunes are the most monitored and studied in the state, park officials say. Both species are listed as threatened under the Endangered Species Act.
As the name implies, the least tern is the smallest of the tern species and resembles a swallow in flight. It is characterized by a black head and yellow bill.
Snowy plovers are even smaller. They can be seen skittering along the surf line and among kelp strewn on the beach, looking for insects. They are gray and white with small black beaks and have a distinctive black patch on their shoulders.
Federal law requires park managers to do all they can to protect the birds and make sure that the two breeding populations do not die out.
"During all daylight hours, we have someone out here keeping an eye on nests and chicks," said Ronnie Glick, a senior environmental scientist who heads the park's monitoring program.
These rare shorebirds have been a lightning rod for controversy for years. Environmentalists have filed several lawsuits, which have been successful in forcing the park to increase its tern and plover protections.
As a result, the park takes a variety of steps to protect them. The main one is the 300-acre seasonal closure area.
From April 1 until the end of September, a mile-and-a-half-long swath of beach is cordoned off with a 6-foot-tall fence. Park visitors and their vehicles must stay out.
Those six months are the snowy plover's breeding season. The tern nesting season lasts half that time — from mid-May to mid-August.
Snowy plovers and least terns are threatened, in part, because they nest on sandy beaches — real estate coveted by people for everything from walking to all-terrain-vehicle riding.
The main goal of the monitoring is to determine the birds' fledge rate. That's the number of chicks that hatch and reach maturity, thereby helping to ensure the continuation of the species.
Specially trained biologists with the Point Reyes Bird Observatory come down and place leg bands on as many of the chicks as possible. The color-coded bands tell biologists which chicks survive and where they go throughout their lives.
"The banding program really does contribute to the body of science for the two species," Glick said.
Glick's crew members also do what they can to make the nesting area as hospitable to the birds as possible. They scatter pine cones and other objects across the sand so nests won't stand out as much to predators.
They place pieces of plywood, which they call tern shelters, so that chicks can hunker down beneath the wood to escape the winds that howl almost constantly across the nesting area.
"It's a pretty inhospitable place for a little bird that's only two inches off the ground," Glick said.
A variety of wildlife prey on tern and plover nests and chicks, including hawks, gulls, foxes and coyotes. Those animals that make a habit of killing the shorebirds are removed. Gulls, foxes and coyotes are trapped and killed while the hawks are trapped and relocated.
The protected status of the terns and plovers trumps considerations for all other species, even if it means killing other wildlife that are native to the area. Gulls and coyotes are plentiful, and red foxes are an introduced species.
As a result of all of this protection, Oceano Dunes has become one of the most important tern and plover breeding sites on the Central Coast.
The terns have been particularly successful. Over the past four years, Oceano Dunes has produced 150 tern fledglings. This compares to 25 tern fledglings produced over that same period from three other sites in Santa Barbara and Ventura counties.
Glick thinks he knows why the Oceano Dunes terns have done so well: They have two sources of food. They can hunt for small baitfish in the ocean as well as small fish from a series of dune lakes just inland of the park.
Plover nesting has been less consistently successful. In a good year, plovers at the Dunes will produce about 50 chicks.
However, every couple of years, they have a bad year, and no one knows why, Glick said.
For example, only 17 chicks were hatched in 2006.
Park managers say the shorebird monitoring program is important because it allows off-road enthusiasts to continue to use the park while protecting two fragile bird species.
"Most people don't know these birds are being protected," Lish said.
Reach David Sneed at 781-7930.