Three thousand tons of sand was added to the nesting grounds for the least terns at Alameda Point in late February and early March. In the weeks that followed, volunteers from St. George Spirits and the Boy Scouts and Cub Scouts came out to help make the site ready for the arrival of the terns in mid-April.
The Water Emergency Transportation Authority (WETA) paid for enough sand to cover half of the 9.6-acre nesting area with three inches of sand, as well as for grading. The weeklong delivery of sand was a conservation mitigation requirement for the impact that WETA’s new ferry maintenance facility will have on the terns’ feeding area. As many as 12 ferries will make up to four passes per weekday through the Alameda Point Channel where the terns frequently dive for small fish.
Wind and water erosion take their toll on the sand substrate lying atop old airfield taxiway pavement, requiring periodic replenishment. This latest delivery of Angel Island coarse sand has built up the sand depth on much of the site to the point that it’s starting to feel like a real beach underfoot. Beaches are the traditional nesting habitat for terns.Continue reading “Ferry agency, volunteers help the least terns”
About 100 California Brown Pelicans made an unusual appearance on the old wooden dock on the south side of Alameda Point near the U.S.S. Hornet on December 23. The visit provided a rare close-up view of this colorful and iconic bird, but also a reminder of their struggle to survive as a species. Only one of the pelicans could be identified as a one- or two-year-old.
During the past four years, the breeding rate for California Brown Pelicans has been dismal. This recent trend has been directly attributable to the dwindling supply of sardines along the California coast, according to a Brown Pelican status report issued in October by the Washington State Department of Fish and Wildlife. The sardine population has dropped so low that in April of 2015, the agency responsible for managing Pacific Coast fisheries banned commercial fishing of sardines until the end of June 2016.
In May, the U.S. Fish and Wildlife Service urged the same agency to consider additional management measures to stave off a decline in northern anchovy, another important food source for pelicans and other marine life.
Brown Pelicans were removed from the federal endangered species list in 2009 with great fanfare after recovering from the devastating effects of the agricultural pesticide DDT on their eggs. But they no sooner recovered from chemical contamination than they fell victim to a plunge in food supply.
“Although most essential nesting and roosting habitat throughout the subspecies’ range is protected, the California Brown Pelican has experienced unusual mortality events and a multi-year decline in breeding success since delisting, both of which appear to be due to the lack of adequate forage,” wrote the U.S. Fish and Wildlife Service to the Pacific Fishery Management Council on May 14, 2015.
About 10 percent of California Brown Pelicans nest on two islands in Channel Islands National Park off the coast of Southern California. The remainder nest and rear their young off the western coast of Mexico.
The University of California at Davis and the Mexican national conservation agency conducted a study of the 2014 nesting season off the coast of Mexico. The U.C. Davis news summary of the study results stated, “The scientists found that this year, areas that typically host hundreds or thousands of nesting pairs held only a few hundred at most, and in some cases zero nesting pairs.” Co-author of the study, U.C. Davis wildlife biologist Dan Anderson, is quoted in the story saying, “That’s what we call a failure, a bust. The bottom dropped out.” Anderson has been monitoring Brown Pelicans for 46 years.
Breeding normally begins in January. Whether the pelicans currently at Alameda Point will make the journey south is yet to be seen.
Breakwater Island along the south side of the Alameda Point Channel serves as the most popular resting site for Brown Pelicans on San Francisco Bay during the warmer months.
Immature Brown Pelicans are distinguishable by being entirely brown, except for their whitish underbelly. By their third year, the neck becomes white and the head yellow. During breeding season, the neck of adults becomes dark chestnut and the pouch under their bill becomes red.
A photo gallery of birds sighted at Alameda Point during the Fall of 2014. They include: Black-necked Stilt, Red-shouldered Hawk, Northern Flicker, White-crowned Sparrow, Cedar Waxwing, Chestnut-backed Chickadee, Northern Shoveler, Black-crowned Night Heron, and Western Bluebird.
Alameda’s nesting colony of endangered California Least Terns has a new government landlord – and a secure home for the future. After years of negotiations, the U.S. Navy transferred 624 acres of its former airfield at Alameda Point to the Department of Veterans Affairs (VA) on Monday, November 3.
The transfer includes the former airstrip that was adopted by Least Terns for nesting in the 1970s and that has become the most productive breeding site in California for that species. More than 500 acres – including the area used by the terns – will be preserved as a wildlife reserve.Continue reading “Endangered Alameda least terns get a secure home”
In early June a pair of returning ospreys looked ready for the day in their newly made nest atop a parking lot light pole at Alameda Point, but they had no chicks to attend to. The pair’s first nest this season — on a nearby ship — had been removed during construction. Their second attempt faced interference from another osprey. By June, hopes for fledglings this year had faded. An ad hoc group of osprey watchers is hoping a dedicated osprey platform can be erected at Alameda Point in a spot where competing interests and annoyances of daily commotion don’t intrude into the reproductive efforts of the ospreys.
In early March the osprey pair began building their first nest this year where they had nested last year — on a kingpost high atop the maritime ship Admiral Callaghan. The ship’s owner, the Maritime Administration (MARAD), had removed last year’s nest. This year MARAD moved quickly to stop the nest building to avoid potential delay to relocate a nest if ordered into service. “The Maritime Administration worked closely with the California Department of Fish and Wildlife on dismantling the nest and installing deterrence devices on March 19 prior to any eggs being laid,” said Alameda resident Harvey Wilson, who has been monitoring the ospreys at Alameda Point.
But that removal didn’t end the ospreys’ interest in the ship, at least not for the male osprey. He soon started bringing sticks to a lower-level hoisting post on the ship. The female, on the other hand, took a liking to a light pole in the parking lot next to the wharf. After weeks of back and forth episodes of mating and nest building at both sites, the female won, and nest building started ramping up on the light pole. At one point, it appeared that the female was hunkering down in the nest, a sign that eggs had been laid and incubation had started. But soon another female osprey appeared, trying to lure the male from his duties and disturbing the composure of the female.
The third osprey now seems to have moved on, and the original pair has continued to visit the nest, but the lateness of the season offers little hope that eggs will be laid again, if they ever were, this year.
The appearance of ospreys at Alameda Point, first documented in 2010, is part of larger Bay Area phenomenon of ospreys beginning to nest on the shores of San Francisco Bay. Osprey first began nesting in the San Francisco Bay Area in the year 2000, having moved their nesting range further south. There are currently 24 active nests on San Francisco Bay. One theory for the ospreys’ Bayside nesting interest is a reduction of silt in the Bay, making it easier for osprey to catch fish, their primary food source. The high silt levels are a legacy of the gold mining era during which streambeds emptying into the Sacramento River were blasted with water canons to expose gold particles.Ospreys normally return to the same nest every year, but the Alameda Point pair has now used three different sites. In 2012 they successfully raised their lone chick on an old light stand on the western jetty of the Seaplane Lagoon, their regular nest for three years. For unknown reasons, they chose the heights of a maritime ship in 2013, and in 2014 a parking lot light pole.
An ad hoc group of osprey watchers that includes members of the Golden Gate Audubon Society have been discussing with the city the possibility of erecting a permanent osprey nesting platform on the western side of the Seaplane Lagoon. “City staff has been and is willing to continue to work with interested members of the local community to potentially establish an osprey platform at Alameda Point,” said Jennifer Ott, Chief Operating Officer for Alameda Point. “The identification of an appropriate location for this platform will depend on a number of factors, including approval by the United States Fish and Wildlife Service.”In March of this year, the city of Richmond’s Public Works Department assisted with the installation of an osprey platform at Pt. Molate, which helped divert nesting efforts from a utility pole with live wires. PG&E, with extensive raptor nesting diversion experience throughout California, has offered to install a pole and nesting tub at Alameda Point for free.
Pt. Molate nest. Photo by Tony Brake.
Pt. Molate nest. Photo by Tony Brake.
Pt. Molate nest. Photo by Tony Brake.
“It is difficult to know what the ospreys feel or how they respond or what their capacity is for all the activity that goes on around them, but this season certainly challenged them,” said Alameda wildlife biologist Leora Feeney. “Providing safe platforms for them out of busy corridors would serve everyone better.”
Osprey with striped bass, maritime ship in background at Alameda Point.
Female osprey after leaving nest and headed to Enterprise Park to gather nesting material.
Female osprey leaving nest to gather nesting material.
Male osprey (right) looking at fish before giving to female.
Male osprey mating with female 2014. Female’s tail feathers visible on left.
Osprey pair deciding on whether to set up nest on light pole in parking lot at Alameda Point 2014.
Frequent roosting area for ospreys in 2014. Female with fish.
The 9.7-acre nesting area for the endangered California least terns at Alameda Point received a new layer of sand this year. Sixty dump truck loads of sand were delivered to the site on the old Navy airfield in March, paid for by the U.S. Fish & Wildlife Service (USFWS).
After the sand was moved into place, USFWS and volunteers set up a numbered cinderblock grid system used for recording behavior and also distributed chick shelters and oyster shells for the chicks to use as protection from the elements and predators.
On Sunday, April 13 a dozen volunteers showed up for the last work party prior to nesting. The task of the day was distributing oyster shells around the site, which provide a nominal amount of sun protection for chicks and, in theory, helps make it more difficult for avian predators like red-tailed hawks and peregrine falcons to spot the chicks amongst all the white shells.
From now until the end of the nesting season in mid-August, volunteers will be participating in another program called the Tern Watch Program. Participants monitor behavior and watch for predators from their vehicles outside the nesting area.
Throughout the nesting season a USFWS biologist makes periodic walks through the site and places numbered plaster markers next to nests so that the number of eggs and success rates can be accurately recorded. If there are three eggs in a nest one week, for example, and one egg the next week with no chicks, it’s an indication that predators have grabbed the eggs.
Each year following the end of the nesting season in August, volunteers at monthly work parties gather up the oyster shells, the wooden A-frames, drain tiles, grid markers, and the hundreds of numbered markers used to identify nests. Clearing the site makes it easier to remove weeds and grade the sand, which can erode during rains. The volunteers pull weeds from inside and around the perimeter of the fenced-in site. The volunteer program during the non-nesting season is organized by the Golden Gate Audubon Society’s Friends of the Alameda Wildlife Reserve committee, in conjunction with the USFWS biologist in charge of the Alameda Point tern colony.
The effort to protect the least terns was begun by the Navy when nesting activities were first noticed in the 1980s. The likely reason for the terns choosing such an unlikely place to nest was the absence of people who might trample on the nests. The nesting site was chosen by the terns, not by the Navy or USFWS, and has been expanded to its current size as the colony expanded. The sandy substrate that approximates the traditional beach nesting habitat for terns is on top of old airfield pavement. Due to erosion caused by wind and rain, the sand has to be periodically replaced, as it was in 2009 and 2011.
Training sessions for this year’s Tern Watch Program will be held at the USFWS office at Alameda Point on April 26, April 30, May 28, and May 31. Volunteers do not have to be a bird expert, just be very interested in observing and reporting about them. Participants are required to attend one training session and commit to signing up for a minimum of three of the 3-hour shifts. Also required are binoculars, cell phone, and personal vehicle. Reservations for the training sessions can be made by calling Susan Euing at 510 521-9717 or by emailing firstname.lastname@example.org. Directions and registration materials will be sent by email.
The annual Return of the Terns bus tour to the nesting area will be held on June 14 this year. The tour departs from the Crab Cove Visitor Center in Alameda. Registration required through the East Bay Regional Park District’s website or at the visitor center.
Featured here is a sampling of the wide variety of birds that enjoy the Alameda Point environment, from the wooded residential neighborhood and wooded parkland, to the shoreline, to the wide open runway area. Most notable of recent sightings is the Golden Eagle, which has been seen off and on for at least a year hunting for rabbits and other prey on the runway area Nature Reserve.