The endangered California least terns that nest on the old airfield at Alameda Point are well protected during their April to August nesting season. Fencing keeps people away from the 10-acre sandy nesting site, but it won’t stop other birds and mammals from getting to the eggs and the helpless chicks. Only a well-armed and outfitted predator management officer can effectively deter other animals.
Every year, the U.S. Fish and Wildlife Service hires a wildlife biologist from Wildlife Services, a division of the U.S. Department of Agriculture. Typically used for protecting crops and livestock, the agency is also hired to protect dozens of endangered species every year. The most recent field report available for Alameda Point is for 2019, obtained through the Freedom of Information Act.
The report describes a variety of methods used to deter or eliminate threats to the nesting terns. First, loud noises and bright flashes of light are fired from a gun to frighten away an avian predator, called hazing. Second, the wildlife biologist drives a vehicle toward an avian predator, another form of hazing. Third, predators are trapped. And fourth, as a last resort, the biologist is left with no other choice than shooting the predator with a shotgun or rifle or euthanizing.
The annual tours to the least tern colony at Alameda Point were sold out again this year. Three groups totaling about 100 people listened to a presentation about the endangered birds before boarding a bus at the Crab Cove Visitors’ Center.
It is the only time that the general public is permitted to enter the federally owned former aircraft runway area to view the terns nesting. Guests are not allowed to leave the bus.
Least tern tour bus parked next to the nesting area on former Navy airfield. San Francisco is in the background.
This once-a-year glimpse of Alameda’s colony, managed by the U.S. Fish and Wildlife Service (USFWS), is very different from the daily opportunities to view the Huntington State Beach least tern colony near Los Angeles, managed by the California Department of Parks and Recreation.
The 9.6-acre Alameda Point least tern nesting site has a 500-acre buffer zone. During the nesting season, volunteers monitor and record tern behavior and threats from predators, such as hawks and falcons, while sitting in their vehicles.
The 13-acre Huntington State Beach Least Tern Natural Preserve is protected by a 15-foot buffer zone on three sides. The Huntington Beach Bike Trail hugs the fourth side of the colony, with the busy Pacific Coast Highway only 40 feet away.
Huntington Beach Bike Trail. Least tern preserve is on the right. Pacific Coast Highway is about 20 feet to the left and out of view. City of Newport Beach is in the background.
At Huntington State Beach, docents amble around to educate visitors about natural history and conservation while recording observations about predators. Over the recent Memorial Day weekend at Huntington Beach, people casting fishing lines into the ocean, throwing Frisbees, and laying on blankets were often not more than 30 feet from adult least terns loafing and sometimes mating on the beach.
Visitors to Huntington Beach viewing the least tern nesting activity on Memorial Day weekend 2015.
During the non-nesting season in Alameda, volunteers remove weeds by hand, and pick up terracotta tiles, wooden A-frames, and oyster shells used for sheltering the chicks, and then re-distribute them in April before the terns arrive. USFWS sprays an herbicide before the terns arrive to minimize vegetation that sprouts up on the bed of imported sand. This is to help to maintain the look of a beach with good sight lines preferred by terns.
At the Huntington Beach Preserve, the state park department stopped using shelters. They, too, use an herbicide, but only for grasses. The low-growing flowering vegetation on this natural beach is allowed to remain and serves as camouflage for nesting adults and for the chicks when they hatch.
Least tern sitting on eggs at Huntington State Beach. The nest is simply a depression in the sand. The vegetation is not part of the nest.
At Huntington Beach, certified volunteers count the nests, eggs and chicks twice a week. They walk through the site inside of sand-colored canvas blinds held together with PVC pipe that they carry. At Alameda Point, the wildlife biologist does not employ the use of a blind.
The Huntington State Beach Least Tern Natural Preserve was established in 1973 as the first fully protected tern colony in California. This preserve implemented the central tenet of the USFWS-approved recovery plan for the least tern by providing a well-defined nesting site that is secure from casual disturbance, primarily by human recreational activity often accompanied by canine companions. The wisdom of this practice is illustrated at Alameda Point: No least terns have ever nested outside of their fence.
The two other determining factors in the breeding success of the terns are the presence of small fish in nearby waters, which can vary due to climate and current, and the presence of predators, which can vary by location. No scientific formula exists to prescribe how far away human activity must be for successful nesting of the terns.
Least tern diving for fish in Alameda Point’s Seaplane Lagoon on June 7, 2015 during the nesting season. Dragon Boat races were occurring nearby.
This year, as of June 20, there were 500 nests at the Huntington Beach Preserve. Alameda Point had a count of 315. There are 27 sites in California that had 10 or more nesting pairs in 2014. Both Alameda Point and Huntington Beach typically rank in the top five. Huntington Beach least tern nesting news updates are posted on the Sea and Sage Audubon Society website. There are no published news updates or progress reports about Alameda Point least tern nesting activity.
The annual Alameda Point “Return of the Terns” tours happen every June.
Originally published in the Alameda Sun.
Huntington Beach photo gallery
Least Tern Preserve with lifeguard tower in the background on the beach.
Cyclists on Huntington Beach Bike Trail on Memorial Day weekend 2015.
Bike trail.
Huntington Beach Bike Trail at the bridge over the Talbert Channel.
Least tern on nest. Vegetation is not part of the nest.
Recording observations about the number of nests, eggs, and chicks.
Recording data in the nesting area.
Least terns on the beach.
Least tern male with fish in mating posture. On the beach outside of nesting area.
Talbert Channel, with Least Tern Preserve in background.
Huntington Beach, with Least Tern Preserve in background.
Santa Ana River. Newport Beach on the left, Huntington Beach on the right.
Side channel in Santa Ana River where the terns bath and hang ot.
Parking lot next to Least Tern Preserve. Bike trail runs between parking lot and tern preserve. Main beach area is to the right.
Sign on fence at Huntington Beach Least Tern Natural Preserve urging people to stay 15 feet away.
Volunteers at the Alameda Point nesting site of the endangered California Least Tern continued their efforts this fall after a successful 2014 nesting season.
Tau Beta Pi members help out during the November 2014 work party. Port of Oakland in background.
The Alameda Point colony produced over 350 least tern fledglings this year, and a record number of the nests had three eggs, as opposed to the usual two. The 45 nests with three eggs may be due to in part to better than normal availability of small fish in nearby waters. The terns arrive at the airfield site in early April. By mid-August the terns have headed south to Mexico and Central America.
Least Tern adult with two chicks – June 2014. Viewed through chainlink fence.
Volunteers distributing oyster shells on nesting site in April 2012
The California Least Terns are arriving back at Alameda Point’s wildlife refuge to lay their eggs and raise their young. The volunteers, who help maintain the site, and the US Fish & Wildlife Service (USFWS) biologist responsible for the tern colony, have never left. They carry out maintenance tasks during the non-nesting season – September to early April – as well as help monitor bird behavior during the nesting season.
California Least Tern, with chick under tile, at Alameda Point
The California Least Terns return to California every April from Central America. The old Navy runway area at Alameda Point is among the limited number of sites where these endangered birds come to nest. Driven to adapt to a loss of undisturbed beach habitat, they began nesting at Alameda Point decades before the Naval Air Station closed in 1997.
While Navy jets would be disturbing for humans to live next to, for the terns the movement of the jets was predictable and easy to avoid. That’s not the case on an increasing number of beach areas where people and pets can easily trample eggs in the sand and frighten the adult birds.
The Alameda Point colony is considered the most successful for this bird. It is believed that the success at Alameda Point has led to new colonies elsewhere in California.
Looking south on a rainy day in April 2012 on the Alameda Point nesting site for CA Least Terns
Oyster shells on Alameda Point nesting site for CA Least Terns
Volunteers are recruited by the Friends of the Alameda Wildlife Refuge, a committee of the Golden Gate Audubon Society. Activity at the Least Tern nesting site started ramping up in January this year as it always does, with guidance from the USFWS biologist. Volunteers perform tasks such as removing weeds, repairing the mesh barrier that keeps chicks from wandering off or getting injured in the chain link fence around the nesting site, and distributing oyster shells to confuse hawks and other flying predators that often circle overhead during the nesting season.
Every year the US Fish & Wildlife Service re-positions all of the numbered cinder blocks that establish a grid pattern for recording bird behavior. The blocks, along with all the other “tern furniture” – wooden A frames and clay tile that chicks shelter under and in, oyster shells, driftwood – are gathered up and set to the side after the nesting season. This allows for easier weed control and for the sand and gravel surface to be graded.
The grid blocks are placed into position using a global positioning system for complete accuracy. When Tern Watch volunteers or the Fish & Wildlife biologist observe activity, they record the data according to a grid letter/number. Without a grid system, it would be difficult to record accurate data for hundreds of eggs and chicks, i.e., did a predator steal an egg last night, or is that the nest that had only one egg?
The public is invited to take a bus tour to the site on June 16th. The annual event is hosted jointly by USFWS and the East Bay Regional Park District. The bus tours leave from the Crab Cove Visitors Center in Alameda. Advance registration is required and is handled through the park district. (See comment below.)
Alameda Point Environmental Report 