Visitors Who Are Welcome, Indeed : Graceful Black Skimmers Settle in Bolsa Chica and Upper Bay

When the first black skimmers arrived at the Bolsa Chica Ecological Reserve in late 1983, naturalists thought the striking black-and-white birds with brilliant red beaks were stragglers, soon to be on their way.

But these birds, native to the Gulf Coast, Atlantic Seaboard and Mexico, stayed on and were joined by more the following winter. Bird watchers and biologists alike were thrilled last August when some of the 55 adults began nesting, producing seven fledglings on a reclaimed oil island within the 530-acre wetland reserve north of Huntington Beach.

Now, with 90 adult black skimmers colonizing the area and nesting activity in full swing this summer, wildlife experts hope that the birds, named for their style of fishing with beaks skimming the water’s surface, will remain.

“I think they’re going to make a go of it, the population is on an upswing,” said ornithologist Charles Collins, a professor at California State University, Long Beach.

At a time when many avian species are dwindling in numbers--as habitat is lost to housing, roads, farms or public beaches--experts say these graceful birds are among a minority that appear to be extending their range.

The Bolsa Chica colony is the third to establish itself in California, after those at the Salton Sea and South San Diego Bay, according to ornithologists. This summer, nesting pairs have been sighted for the first time in Upper Newport Bay and near the Kern National Wildlife Refuge in the San Joaquin Valley.

“It certainly represents quite an extensive increase in their range, and they are giving every sign that they won’t stop here,” said Collins, who along with graduate students closely monitors bird populations at Bolsa Chica.

“I would think it very likely they might colonize an area like Pt. Mugu, and we may very well see them filling in the gaps at Camp Pendleton or lagoons to the south in San Diego County.”

But some experts caution that Atlantic and Gulf Coast skimmer colonies are cyclical by nature, wandering in search of a plentiful supply of small fish and secluded sandy beaches free from predators, human intrusion and flooding. Should conditions change at Bolsa Chica, they say that the birds could abandon the island for a safer place.

At the same time, they say the skimmers’ expanding range, probably from coastal Mexico, is largely the result of efforts to protect and upgrade California’s diminishing coastal wetlands. At Bolsa Chica, skimmers are unintended beneficiaries of the state Department of Fish and Game’s efforts to restore tidal flushing and upgrade two former oil islands for the endangered California least tern.

“I don’t think there’s any large scale indication across the country of skimmers expanding their range, but it is probably true in California, because there has been a much more conscientious effort to provide beach habitat that is protected,” said sea and water bird expert Joanna Burger, biology professor at Rutgers University in New Brunswick, N.J.

“Which is what a bird like the skimmers needs,” said Burger, who has studied black skimmers in New Jersey, where they have been on the endangered list for the last 10 years.

“It shows that we can manage coastal wetland habitats for successful breeding of water birds,” said Kimball L. Garrett, ornithology collection manager for the Natural History Museum of Los Angeles County. “We’ve done so much the other direction, destroying coastal habitat, that these kinds of positive signs are very important.”

The global importance of the colony aside, the arrival of resident black skimmers has been one of the biggest events for Orange County birdwatchers since a stray skimmer was sighted Sept. 8, 1962, at the mouth of the Santa Ana River, several miles south of Bolsa Chica.

“It is an important event,” said Sylvia Raney, an amateur field ornithologist with Orange County’s Sea and Sage chapter of the National Audubon Society. “It’s a fascinating bird to watch, flying along feeding with their beaks dangling in the water.

Almost Part ‘Your Hair’

“When they fly in a tight flock, back and forth, they fly low over your head, almost parting your hair,” said Raney, who has been chronicling the growing colony through photographs.

Black skimmers, which are medium-sized water birds closely related to gulls and terns, are found in coastal bays, estuaries, ocean beaches and salt marshes from Massachusetts to Florida and Texas, along the Atlantic and Pacific coasts of Mexico and in parts of South America, according to the National Audubon Society. Occasionally, they seek out inland bodies of fresh water, mainly in Florida.

At Bolsa Chica, skimmers have colonized the northernmost of the two oil islands, which were enlarged and topped with tons of sand to attract the least terns, which, like skimmers, nest on the ground.

Skimmers are easily recognizable by their protruding lower beak, which is uniquely contoured for trolling swiftly through the water. While other nocturnal birds, like some terns, have developed acute eyesight for night-time diving for small fish, skimmers simply fly low over the water’s surface, their wedge-shaped lower beak knifing through the ripples. They skim in one direction, leaving a wake of bubbles that attracts fish. Then, they return in the opposite direction, scooping up dinner.

Normally shy, skimmers become aggressive when humans or predators draw near and will fly together in wedge formation, swooping near intruders to frighten them away from their nests, which are mere scrapes in the sand.

When researchers visited the island recently to survey the colony, some adult birds squawked and dove low overhead from the time the biologists set out in a rowboat for the sandy hillock until they left an hour later. Several birds became more agitated when refuge manager Dan Yparraguirre and Collins picked up a chick to measure and band it.

“Hello squirt, how’re you doing?” Collins asked, ignoring angry adults overhead as he bent down to pick up a dun-colored chick hiding near a bush. The chick was estimated at less than five days old.

Researchers must step carefully because the chicks and eggs, with their brown speckling, become almost invisible against the sand and brush on the island.

Unlike endangered California least terns, which can co-exist on beaches with sunbathers nearby, skimmers require a protective buffer, often a wide body of water.

“With skimmers . . . you really almost need 50 or 100 meters of space separating them from people,” said Rutgers biologist Burger.

The island settled by the skimmers at the ecological reserve is off limits to the general public to avoid disturbing them and nine other species of nesting birds, including more than 100 endangered least terns.

Last August, about 7 to 10 skimmer chicks survived from about 20 eggs. So far this year, 50 chicks have hatched from 176 eggs. Although the season is not yet over, researchers say this year’s survival rate is lower and there are signs of predator disturbance.

“Many of the chicks hatched and died--we don’t know why,” Yparraguirre said.

Several weeks ago on the island, researchers spotted mice, which are capable of eating skimmer and least tern eggs. Tracks from a dog-like animal also have been found. Collins said it was impossible to tell whether they belonged to pets from nearby homes, wild dogs or possibly red foxes, which have been preying on least terns and the endangered light-footed clapper rail at the Seal Beach National Wildlife Refuge a few miles away.

Mouse traps can be set, but Yparraguirre said there is little that can be done to keep out canines that don’t mind getting wet and muddy from fording shallow waters around the island.

After the first California sighting in Orange County in 1962, black skimmers next appeared at the Salton Sea in 1968, and at the salt ponds of South San Diego Bay in 1971.

“They just appeared out of the blue here in California,” Garrett said.

Now, there are about 350 pairs of skimmers nesting at the Salton Sea, according to amateur field ornithologist Guy McCaskie, the Southern California regional editor for the Audubon Society’s quarterly publication, “American Birds.” In San Diego Bay, 290 adult black skimmers and at least 25 chicks were counted in July by amateur field ornithologist Richard Webster, who supplies his data to McCaskie.

In Upper Newport Bay, two skimmer nests were found for the first time this summer on an island in the state wildlife reserve. So far, one chick has been hatched, said Kevin Foerster, a Department of Fish and Game research assistant and graduate student of Collins.

In Kings County, just north of the Kern National Wildlife Refuge, a pair of skimmers wandered far inland to nest alongside seasonal agricultural runoff ponds on Tulare Lake Drainage District land, according to Robert B. Hansen, manager of four wildlife refuges owned by the Nature Conservancy in Tulare and Kern counties. So far, the nest has produced two chicks.

“This is very significant, because as far as I know, this is the first record, period, of skimmers in the San Joaquin Valley,” said Robert Barnes, a field ornithologist in Tulare and Kern counties. “To have them so far inland is unusual, and it’s a big, big range extension from the Salton Sea and Bolsa Chica.”

Garrett said it was difficult to know whether the Kings County sighting is “a fluke or the vanguard of the colonization of the San Joaquin Valley.”

But he said it would appear that the three-year-old Bolsa Chica skimmer colony is here to stay.

Skimmers are not the only new species to colonize Bolsa Chica. A flock of 45 Caspian terns nested there for the first time this summer, producing 17 chicks on the reserve’s southernmost island, Foerster said.

Also new to the reserve is a flock of more than 100 elegant terns, far more rare than the larger Caspian variety common along the Pacific Coast. Collins and reserve managers were hopeful that next year the elegant terns will establish their second U.S. breeding colony, the first being in South San Diego Bay.

Not bad for a former oil well island.

To what does he attribute the sudden increase in new species of birds in the Bolsa Chica reserve? Yparraguirre said with a grin: “They like my management of this preserve.”

In a more serious tone, he added: “It just goes to show how elastic bird species can be if you manage the habitat properly.”