Marjorie Powell is a member of the Golden Gate Audubon Society.
Egrets Thrive in Island City Habitats
Alamedans who have visited Alameda’s shoreline parks, Elsie Roemer Bird Sanctuary, Crown Beach or Seaplane Lagoon have likely seen the elegant snowy egret. The Audubon Society’s Guide to North American Birds describes the snowy egret as, “A beautiful, graceful, small egret, very active in its feeding behavior in shallow waters. Known by its contrasting yellow feet, it could be said to dance in the shallows on golden slippers.”
As the name implies, the snowy egret is pure white, with a long, slender, black bill, a yellow patch at the base of the bill, black legs and distinctive yellow feet. It stands about 2 feet tall with a wing span of about 3 feet — still considered “small to medium” by heron and egret standards.
Its larger, also pure white cousin, the great egret, stands more than 3 feet tall with a wing span of up to 57 inches. The size difference becomes clear when the two birds are seen together, which happens often. Despite their size, however, the snowy egret weighs less than a pound and the great egret just a little more than two pounds.
Its chosen wetland habitats afford the snowy egret a diet of: fish, crabs and crayfish, but also such varied delicacies as frogs, snakes, insects, snails, worms, lizards and even rodents.
The snowy egret breeds in colonies, often mixed with other species of wading birds. The male selects the nest site and displays there to attract his mate. Together they build a platform-style nest of well-arranged sticks, generally about 10 feet off the ground in a tree or large shrub. The female then lays three to five, pale blue-green eggs. Both parents incubate their young over 20 to 24 days. Both also feed the young. Maturing chicks may clamber out of the nest after 20 to 25 days, but are probably unable to fly before 30 days.
Here in Alameda, a mixed colony of snowy and great egrets thrives on Bay Farm Island, near the branch library, in the pine trees across from the day care center, along the edge of the lagoon.
The colony birds generally begin building nests in late February or early March, with the breeding and chick-raising cycle complete by the end of August. At that point the adults and young birds disperse to feeding and roosting locations throughout the area. Individual birds can easily be seen year-round at the locations mentioned above.
It is interesting to note that both the snowy and the great egret were hunted to near extinction for their plumes in the 19th century. The efforts of early Audubon Society conservationists resulted in passage of the Migratory Bird Treaty Act of 1918, which ensured the birds’ protection and a complete recovery of their numbers.
Today, the snowy egret is widespread and common in coastal and wetland areas throughout the country. A silhouette sketch of the great egret by famed artist and ornithologist, David Sibley, became the official logo of the National Audubon Society.
Alameda’s shoreline testifies to Alameda’s clean waters but also highlights the need to avoid toxic spills as well as plastic pollution of the city’s marine habitat. To learn more about efforts to protect and restore bird-safe shoreline through the San Francisco Bay Area or more information about Alameda’s local birds, visit the Golden Gate Audubon website, www.goldengateaudubon.org.