by Carolyn Jones from "San Francisco Chronicle" [http://www.sfchronicle.com/science/article/California-least-terns-thrive-in-Bay-Area-4608311.php]:
A fluffy California least tern chick. (Ian C. Bates, The Chronicle)
It's party time in Tern Town.
About 150 very elusive, highly endangered California least terns have taken up summer residence on a three-quarter-acre island on the Hayward shoreline, creating a noisy, busy nesting colony that's among the most prosperous tern enclaves on the West Coast.
Dubbed Tern Town by the biologists who monitor it, the island is a flat expanse of oyster shells and sand just north of the San Mateo Bridge toll plaza. Isolated and quiet, it's a perfect habitat for the diminutive, elegant shorebirds.
"I am ecstatic they're doing so well," said David "Doc Quack" Riensche, a wildlife biologist for the East Bay Regional Park District who oversees Tern Town conservation efforts. "It's beautiful to see them hovering in the wind. ... Our world would be much poorer without them."
In the early 1970s, only about 1,000 pairs of California least terns remained along the Pacific Coast, from the southern tip of Baja California to the Bay Area. Mostly, they were victims of habitat loss. Urbanization of the coast, which destroyed nesting areas and ushered in predators like feral cats and raccoons, left the birds with little hope of survival.
Since placement on the state and federal endangered species lists in the early 1970s, the birds have slowly recovered. Their nesting grounds are protected and scientists and volunteers help create shelters for them.
Now California least tern pairs number about 5,000 spread across 33 colonies. Although most are clustered in Southern California, two significant colonies are in the Bay Area: the runway at the former Naval Air Station in Alameda and Tern Town on the Hayward shoreline.
Park district biologists and volunteers built Tern Town in 2001 in hopes of bringing the birds back to the shoreline, where a century ago they were plentiful members of the local bird population. Volunteers and staff built the island by hand, dumping 3 1/2 -gallon buckets of clay, sand and oyster shells in the middle of an old salt pond.
The project took over four years to complete, but then came the hard part: attracting terns. Staff set out solar-powered speakers with amplified sounds of terns mating.
"We tried to make it a tern singles bar," Riensche said. "Like this is where all the terns were coming for a good time. It worked."
The next challenge was fending off critters that snack on tern eggs and chicks. Staff set out several effigies of dead seagulls, and at critical times played audio recordings of seagulls under attack.
"Hear this?" Riensche asked, as he played a horrific screeching recording. "That's the sound of a gull having a very bad hair day. It scares the gulls away but the terns don't seem to mind it. In fact, they get sort of excited."
Volunteers are a critical part of Tern Town. They play the gull-horror tapes and scare away raccoons and red foxes in two daily shifts, morning and dusk. They also help count nests.
Tierra Groff, a former UC Davis biology student who interned at Tern Town, was immediately taken with the graceful birds.
"I didn't know much about terns when I started, but I became obsessed," she said. "They're in the same family as gulls, but are more elegant, more sleek. And they have a really quirky personality."
California least terns are about half the size of seagulls, with striking white bodies, pointy wings and black heads. They flutter and dart over Tern Town, chattering loudly as they deliver anchovies and smelt to their offspring.
The babies are fluffy and mottled, perfectly camouflaged against the oyster shells and sand.
Tern Town is off-limits to the public because of its sensitive ecology, but the public can watch the terns from the nearby Bay Trail and can volunteer.
"That's what I really loved - that with the public's help, how relatively easy it is to turn a species around," Groff said. "It was an amazing experience."
How to help -
To volunteer or donate to help the California least tern colony, call (888) 327-2757 or go to [www.ebparks.org/getinvolved/volunteer/quack]