Volunteers Help Terns

Richard Bangert The city of San Francisco provides a backdrop for a road grader smoothing out sand on the least tern nesting site at Alameda Point. The Water Emergency Transportation Authority funded the sand delivery as mitigation for the impacts of ferry traffic at its new maintenance facility planned for Alameda Point.

 

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 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 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.

In March, virtually all the employees of nearby St. George Spirits showed up on a rainy Sunday morning to help distribute cinder block grid markers and clay tile chick shelters throughout the site. The high-spirited and determined crew trudged through puddles of water determined to get the job done regardless of how wet they got. Some volunteers worked in the old Quonset hut repainting and numbering the plaster markers that the Fish and Wildlife Service uses to identify each nest. Others re-stenciled cinder blocks.

The cinder blocks and the plaster markers allow for systematic data collection on nesting success. The blocks and markers were removed prior to the sand delivery and grading work.

In April, Alameda Boy Scouts Troop 73 joined the Cub Scouts from Pack 1015 for the final preparations for the least tern arrival. 

“Overall, 25 youth from the fourth to 12th grade and 15 parents joined this final chilly work day putting out oyster shells, flattening the area after a week of rain and pulling the last of the weeds,” said Dorinda von Stroheim, Webelos Den Leader Pack 1015.  “The kids loved placing the shells and took extra care to make sure all the shells were evenly distributed.” 

The scouts were supposed to get pizza delivered at noon, but they hustled through their assignments so quickly that the pizza parlor was not even open yet. They accepted a rain check from the Audubon Society. 

The least terns, an endangered species, have enjoyed phenomenal success on the old airfield at Alameda Point. Pushed to the brink of extinction by human encroachment on their traditional Southern California coastal nesting areas, the terns began taking up residence on a number of military bases in California during the past four decades. With early and continued stewardship by the Navy through 2014, and the addition of volunteers after the base closed, the Alameda Point colony went from a few nests to more than 300 today. 

During the 2015 nesting season, the Alameda Point terns were the top performers statewide, both in terms of the total number of fledglings produced, and the key data point — ratio of fledglings per nest — according to recently released data. 

The public is invited to see the terns during the annual “Return of the Terns” event on Saturday, June 18. Tours by bus leave from the Crab Cove Visitor Center after an educational presentation. Reservations are required for one of the three tours via the visitor center, or the East Bay Regional Park District’s website https://apm.activecommunities.com/ebparks using the search keyword “terns.”

 

Richard Bangert publishes stories and photos about wildlife on the Alameda Point Environmental Report.