The nesting site was chosen by the terns, not by the Navy or U.S. Fish & Wildlife Service.

The 9.7-acre nesting area for the endangered California least terns at Alameda Point recently received a new layer of sand. On Sunday, April 13, a dozen volunteers showed up for the last work party prior to the nesting season. Sixty dump-truck loads of sand were delivered to the site on the former Alameda Naval Air Station’s runways in March. U.S. Fish & Wildlife Service (USFWS) paid for the project.
Once workers moved the sand into place, USFWS joined volunteers to set up a numbered cinderblock grid system for recording least tern behavior. They also distributed chick shelters and oyster shells for the chicks to use as protection from the elements and predators. The shells make it more difficult for avian predators like red-tailed hawks and peregrine falcons to spot the chicks
The task of the day was distributing oyster shells around the site. The shells provide a nominal amount of sun protection for chicks and, in theory, help the chicks hide.
From now until the end of the nesting season in mid-August, volunteers will participate in another program called “Tern Watch.” Participants monitor behavior and watch for predators from their vehicles outside the nesting area.
Throughout the nesting season a USFWS biologist will take periodic walks through the site and place numbered plaster markers next to nests so that the Wildlife Service can accurately record the number of eggs and success rates. 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 gather up the oyster shells, the wooden A-frames, drain tiles, grid marker and the hundreds of numbered markers used to identify nests. Clearing the site makes it easier to remove weeds and grade the sand, which rain can easily erode.
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 least 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 this Saturday, April 26; Wednesday, April 30; Wednesday, May 28; and Saturday, May 31. 
Volunteers do not have to be bird experts, just be very interested in observing and reporting about the least terns. Participants are required to attend one training session and commit to signing up for a minimum of three of the three-hour shifts. Also required are binoculars, cell phones and personal vehicles. 
Reservations for the training sessions can be made by calling Susan Euing at 521-9717 or by emailing susan_euing@yahoo.com. 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 Saturday, June 14. The tour departs from the Crab Cove Visitor Center. Registration is required through the East Bay Regional Park District’s website or at the visitor center.
Read more Alameda Point news at Richard Bangert’s blog http://alamedapointenvironmentalreport.wordpress.com.