Environment : Notes about your surroundings.

Shore Birds--”Fall migration is in full swing,” reports Sylvia Gallagher, bird information chair for the local Sea and Sage Audubon Society. “The shore birds are back in great number.”

Many of the birds that have arrived in the past month are still in their breeding plumage and some are juveniles, which can provide an extra challenge to birders. “They’re kind of a bewildering crew right now,” Gallagher said. The Upper Newport Bay and Bolsa Chica coastal wetlands areas are the prime local viewing spots.

The land bird migration should begin in late August or early September, Gallagher said. Many land birds that breed in Southern California are off their nests and more active, part of a phenomenon called post-breeding dispersal.

Tern Report--Bolsa Chica’s breeding population of elegant terns continues to explode, according to Esther Burkett of the state Fish and Game department (terns are a family of gull-like birds). Until recently, elegant terns were not known to breed north of San Diego Bay. In 1986 some mating activity was observed at Bolsa Chica but none of the birds nested; the next season, 30 pairs nested in Bolsa Chica.

Last season, 450 pairs nested, most of them on the ecological reserve’s north island. This year, according to Burkett, an astonishing 900 to 1,000 nests were counted, producing about 850 successful chicks.

Numbers for two other recent arrivals at Bolsa Chica--black skimmers and Forster’s terns--seem to be about equal to last season, Burkett said. There seems to be some competition for limited breeding space, as most of the Forster’s terns nested in the high pickleweed rather than on the nesting islands.

Biologists are still tallying exact figures for the endangered California least terns that nest at Bolsa Chica, but Burkett said about 130 nests were counted on the south island, roughly equal to last year. While there were no signs of egg predation by red foxes or other animals, some of the least tern fledglings became meals for American kestrels, a small species of falcon. Seven kestrels were trapped and relocated.

In addition, eight snowy plover nests were counted at Bolsa Chica, five on the north island and three on the south. This small shore bird is listed by the state as a species of special concern and is a candidate for federal endangered species listing.