The Graceful Beauty of Egrets and Herons

The brilliant white plumage of the great egret (Ardea alba) gives this bird a grace and beauty that is unparalleled in the natural world. Egrets are a type of heron, members of the Ardeidae family, which has 59 species that range all over the world. The great blue heron (Ardea herodias) is the largest of North American herons and is found throughout the continent. The snowy egret (Egretta thula) is smaller than the great egret and is notable for its wild shaggy plumage during breeding season. It has a slim black bill, which distinguishes it from the yellow-billed great egrets.

Egrets and herons play an important role in the symbolism and mythology of many cultures around the world. The heron is a central figure in the creation myth of the Aztecs, who trace their origins back to Aztlan, "the place of the herons." The Maori of New Zealand refer to the great egret as Kotuku, a spirit messenger who symbolizes that which is rare and beautiful in the world. In ancient Greece, the heron was regarded as a messenger for Athena, the goddess of wisdom. Homer described this role in The Illiad:

Off to the right along their path, Pallas Athena sent a heron gliding down the night. They could not see it passing, but they heard its cry; and heartened by that fisher bird, Odysseus prayed 'O child of Zeus who bears the storm cloud, hear me... tonight, befriend me most, Athena...' These were the prayers, and Pallas Athena, Zeus’ daughter, heard them.

The great egret came close to extinction in the late 19th century, when Victorian era fashion placed a high value on the white feathers for use in the decoration of hats and headdresses. The French word for egret, aigrette, became synonymous with the millinery ornamentation that was crafted from the tufted crests of egrets. Public reaction to the wholesale slaughter of egrets brought an end to this fashion trend, and steps were undertaken to protect the birds. The National Audubon Society was founded in 1905, partly to stop the killing of egrets for their feathers. Later, an image of a great egret in flight became the symbol of the National Audubon Society.

Great egrets are the main players in one of the most fascinating wildlife shows in the Bay Area right now. They have arrived at the Martin Griffin Preserve, in the forested hills above Bolinas Lagoon. They have come to court each other and mate, build their nests, lay their eggs and incubate them, and teach their young brood how to fly. This annual rite of passage begins when the birds arrive in March or April, starting off with elaborate courtship rituals. The male egret postures toward the females, extending the plumes on his back, feathers that are only present during mating season.  When one of the females accepts the invitation, they both posture with extravagant displays of feathers, raised wings, and sometimes a ritual twig presentation.

The egrets then build their nests, high in a grove of old-growth redwoods just inland from Bolinas Lagoon. The nests can be viewed from the Henderson Overlook, which is reached by a short half mile hike from the entrance to the preserve. The trail goes up Picher Canyon, through a tranquil forest of Douglas-fir, coast live oak, and California laurel. The forest floor is deep in shade, permeated with bracken ferns, swordtail ferns, and delicate irises. Slimy banana slugs and meandering newts creep slowly across the trail, making careful footing a necessity.  It is serenely quiet, but for the orchestra of birdsong that rings out from the tree tops.

Looking across the canyon from the Henderson Overlook, the egrets can be observed from a distance safe enough to avoid disturbing them at this sensitive time in their life cycle. On a recent day, there were 17 nests present, with birds coming and going, taking turns to fly down to the lagoon for a quick feeding. To the naked eye, the egrets appear to be a flurry of white patches in the tops of the redwoods. Much more can be observed with binoculars, which allow a direct view into the nests, where the birds stand guard over their eggs. Each nest will generally have from two to five eggs, which will hatch in about 28 days. Both parents take part in incubating the eggs and caring for the hatchlings. The young birds can fly in about two months after hatching.

The Martin Griffin Preserve is located on a former dairy ranch that still has its old farmhouse, milking barn, and various outbuildings. It is part of the Audubon Canyon Ranch, a network of nature preserves in Marin and Sonoma Counties. Founded in 1962, Audubon Canyon Ranch was established to preserve the stand of old-growth redwoods that now serve as the heronry for the Martin Griffin Preserve. The 503 acre ranch has been expanded over the years and now totals more than 1,000 acres.

The preserve has eight miles of trails that traverse the slopes of Bolinas Ridge and up to the forests of Mount Tamalpais. For first time visitors, an easy one-mile loop route goes up the Kent Trail to the Henderson Overlook, then back down on the Griffin Loop Trail to the Clem Miller Lookout. From here, the view takes in the rich habitats of Bolinas Lagoon. At the entrance to the preserve is the Aileen Pierson Marsh, a serene buffer from the traffic of Highway 1. A short drive into the preserve is the main visitor area. There is a bookstore, where visitors can register, as well as a picnic area, restrooms, and interpretive exhibits in the Display Hall. Educational programs are conducted on weekends, about the heronry and other natural history topics.

The Martin Griffin Preserve is open to the public each year in the spring, from mid-March until mid-July. This year it will be open until July 14. The preserve can be visited on weekends and holidays, 10:00 AM to 4:00 PM, without an appointment. Appointments are necessary for weekday visits, Tuesday through Friday, 10:00 AM to 4:00 PM, and can be obtained by calling (415) 868-9244. Admission is free, and donations are welcome.