While we’ve all focused on the drama provided by the bald eagles at Corica Golf Course, other birds have been quietly, or perhaps not too quietly, nested in their usual spots at opposite ends of Alameda.
Great blue herons
On the West End, on the Veterans Affairs’ Reserve but viewable from De-Pave Park, great blue herons continue to nest in two dead trees. Herons nest in colonies, with several nests in one tree, expanding to more trees as the colony grows. Their acidic poop eventually kills the nest tree, which is why the two trees in the Reserve are dead.
To see the great blue herons sitting on their nests, drive to the southwest end of Monarch Street, past the old airplane control tower, through the gates, just past Building 25, where the wine tasting rooms are located. Park along the fence and look toward San Francisco. You will see two dead trees, each with large stick nests with large grayish birds sitting or standing on the nests. The trees held more nests in past years, but as the brittle branches break, the nests fall. I’ve been watching the nests each spring for the last 10 years, but the trees have hosted the herons for even longer. This year, seven nests survived all the wind and rain. We hope these birds will hatch eggs and feed chicks that will fledge and add to the island’s population of Great Blue Herons.
The great blue heron is a large gray bird with a yellow bill and a thick black line behind the eye which, during the spring breeding season, leads to a black plume that flows behind as the bird flies. In the air, the birds look like flying dinosaurs, with large wings beating slowly and long legs trailing behind. great blue herons are mostly silent unless they are disturbed, which happens often in the nesting colony. Their response is a loud squawk, a sound that seems totally wrong for such a stylish bird. They eat fish, crickets, frogs, and other small insects and animals, so they search for food in shallow waters and in fields. They often stand patiently waiting then swiftly seize the fish, swallowing it whole.
Snowy egrets
At the other end of Alameda two other members of the heron family breed in the trees that line the lagoon behind the shopping center on Bay Farm Island. To see them there, walk along the lagoon behind the library and look up in the trees, watch for white poop spots on the ground, or listen for the squawking. Look for large and small white birds, both with long legs. The larger birds, great egrets, are white with a yellow bill and black legs. During the breeding season, great egrets sport a lime-green line between their bill and eye, and long white plumes flowing from their back. They stand about three feet tall and weigh just under two pounds. The females are slightly smaller than the males.
The smaller birds, snowy egrets, are white with a black bill, black legs, and golden yellow feet— “golden slippers.” At about two feet tall, they weigh about 1.5 pounds. Both snowy and great egrets are colony nesters like great blue herons, but the two egrets will share the same nest trees. At the nest colony, great egrets make a squawking sound that can get loud when several birds squawk at once. Snowy egrets also make a harsh call when disturbed, a sound that is also magnified when several birds join in. The Bay Farm Island colony is smaller now than it was a few years ago—at least one tree killed by the birds’ acidic poop was removed after the nesting season because it posed a hazard to people walking around the lagoon.
Egrets nest by the lagoon because they are fish eaters. Snowy egrets also eat snails, crabs, snakes, and various insects. Great egrets also eat fish, crabs, and insects, but being larger, they can and will eat small mammals and small birds, including chicks of other bird species nesting nearby, such as mallards and sparrows.
After the snowy egret chicks fledge, the juvenile birds hang out along the shoreline on Bay Farm Island as well as Elsie Roemer Bird Sanctuary and Crab Cove on Alameda Island. I don’t see nearly as many juvenile great egrets in those spots, so they may travel further from the nesting area after they learn to fly and feed themselves.
Herons and egrets can be seen in Alameda year-round, but it’s possible that some of the birds here in the summer go south for the winter, and that birds that breed further north may come here for the winter. It’s fun to see that their nesting sites look so similar.
Marjorie Powell moved to Alameda from the East Coast in 2014 and first joined the Oakland Christmas Bird Count in 2019. A member of Golden Gate Audubon Society, she serves on its Alameda Conservation Committee, the Friends of the Alameda Wildlife Reserve, and tries to go birding frequently.
