Conservation is making strides this summer with enhanced protection of the endangered California Least Tern in Ocean Beach. Starting June 3, volunteers from the San Diego Audubon Society will be on hand at the nesting site of the birds on the east end of Dog Beach at the mouth of the San Diego River.
The project, which will run through the end of the terns’ nesting season in mid-September, is spurred on by a recent increase in predation that threatens the recovery of the birds, which have been on the endangered species list since the inception of the Endangered Species Act of 1970. The nesting site, protected by a temporary fence, is one of four in the Mission Bay area and one of nine in San Diego County (others are at the Santa Margarita River mouth, the Batiquitos Lagoon, NAS North Island, Coronado’s Silver Strand and the Tijuana River mouth).
According to Chris Redfern, Audubon volunteer coordinator, Least Terns and their eggs have a number of natural predators, including ravens, crows, kestrels, coyotes, ants, cats and dogs. Last year, a promising popoulation of 130 chicks was decimated by a pair of kestrels living nearby. By monitoring the area and alerting biologists to the situation, volunteers were able to save 10 chicks and it is hoped that a greater presence at the site will provide better results this year.
Volunteers will also have to monitor the fence around the site because it only provides partial protection when the sand beneath it washes away, leaving an opportunity for dogs to wander in and destroy eggs.
The terns moved to the Dog Beach nesting site three years ago to escape increased urban predation at Mariner’s Point in Mission Bay. The San Diego Department of Parks and Recreation, which owns the beach, put up a fence to protect the area, and volunteers from various organizations, including the Audubon Society, helped to weed it to the 10 percent vegetation ratio that the birds prefer.
“The challenge is knowing which predators affect the site in a particular year, since there are differences every year,” Redfern said, noting that the birds are very picky and leave the area when they feel threatened.
This sort of sensitive behavior explains why the birds are still considered endangered. Human encroachment and development led to a total of 500 pairs in San Diego County in the 1970s. Their numbers have increased to approximately 4,000 today due to efforts by park rangers, conservation groups and the military. Nevertheless, only approximately 10 percent of the terns’ habitat is natural “” most is carefully planned and maintained by interested parties. The Mariner’s Point site produced 50 chicks last year.
The Dog Beach nesting site is not without a controversial history. Being a public beach, the creation of a temporary fenced-off area, from April 15 to September 15, did not sit well with many dog owners the first year. However, the past two years have led to greater cooperation and understanding between the users of the beach and the conservation groups.
Redfern emphasizes that the greatest factor has been education of the public. “Once people understood, they were totally cool with it. People have been very respectful. It’s been wonderful,” he said.
Redfern added that one of the main goals of the volunteers will be to make users of the beach aware of the situation, as well as keep people and animals out of the nesting areas. Besides predation, terns have also had to cope with a decline of food due to changing climates and recent congressional efforts designed to weaken the Endangered Species Act.
“It’s a pretty unique opportunity to come and help out an endangered species,” Redfern said.
Since the beach is used lightly during the week, tern monitoring will take place on the weekends through September 15, 8 a.m. “” 5 p.m., with volunteers taking three-hour shifts.
Those interested in volunteering for the program should contact the San Diego Audubon Society at (619) 682-7200.