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Returning Least Terns Find Expanded Home at Alameda Wildlife Refuge |
In late April and May, when a colony of California Least Terns completed its arduous, roughly 2,700-mile trip from Latin America to nest at the Alameda Wildlife Refuge, a pleasant surprise awaited them. They found their old nesting site had nearly doubled in size to over nine acres! The birds also found their nesting area lined with a new, oyster shell ground-cover for camouflage and the entire area protected by a specially designed, rabbit-proof fence. Such a welcome home for the endangered terns is due to the dedicated efforts of Golden Gate Audubon’s Friends of Alameda Wildlife Refuge (FAWR) and to U.S. Fish and Wildlife Service (FWS) biologists. The terns also have to thank a class of 50 children from West End Alameda elementary schools, who spent a day in March spreading new oyster shell ground cover for the birds’ benefit.
Successful breeding and higher numbers of terns nesting in Alameda over the last 20 years appeared to be causing density bickering. Chicks would sometimes wander into other terns’ territory and get hammered with a pointy beak. More than 300 nests seemed to be too many in less than six acres.
Led by biologists Chris Bandy and Rachel Hurt, FWS found the means to expand the colony. The U.S. Navy still owns the land that has been proposed for the Alameda Wildlife Refuge, but the tern colony and the area’s wildlife resources are managed by FWS. After initial delays in the project—such as the difficulty in finding contractors willing to install a new fence with recycled materials—the nesting-site expansion was completed just in time, and last-minute details were finished before the terns’ arrival. The new fencing is designed to keep jack rabbits out of the colony. New fence poles are cut lower than the top of the fence to remove larger avian predator perches. The old fence (installed in the 1980s) was not entirely chick-friendly. The new fence offers a gentle barrier between the nest site and the outside world with a smooth plastic mesh border placed along the inside bottom of the chain link fencing.
The new ground substrate is a coarse, heavy sand from Angel Island. A load of oyster shell was brought in and added for chick shelters and predator distraction. And a new cinder-block grid system has been installed for keeping track of nest locations.
While so much habitat has been reduced or lost altogether for so many birds, GoldenGate Audubon and its tireless volunteers are proud to have an enlarged and safer habitat for these remarkable little terns. It will be interesting to see where they settle. Will they use the new area for nesting or prefer their old, familiar grounds? Come and see for yourself on the “Return of the Terns Day” on Sunday, June 13th.
-Leora Feeney, FAWR Chair & biologist
