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As part of the Centennial Park Restoration Project, the Napa-Solano Audubon Society conducted a series of bird surveys here in the Park and created a species list - click here for the Centennial Park Bird List.

Although there are almost 100 species of birds documented in the park, some of the easiest to see are those belonging to the Ardeidae family –the herons and egrets.  These beautiful birds are quite large and colorful and are often found standing still on the edges of wetlands.  Five species of Ardeids have been observed in Centennial Park, including great blue heron, great egret, snowy egret, cattle egret, and green heron.

Herons and egrets are all strictly carnivorous and most eat a variety of fish, frogs and other aquatic creatures.  Their long legs, necks and bills are all specially-adapted to allow them to hunt effectively in wetlands.  Their long legs allow them to easily wade in shallow water.  The vertebrae in their long necks are modified, allowing the birds to draw their necks back into a tight S shape and then shoot forward with great speed like a harpoon.  Finally, their long sharp-pointed beaks are perfect for spearing prey.

_{Great blue herons are often seen hunting in wetlands for fish and frogs.  Photo credit: David Davies}

Different species of Ardeids utilize different hunting strategies. Great blue herons and great egrets practice what is known as “standing in wait” and “peering” - they will hold perfectly still looking intently in the water, occasionally shifting their head to enhance their binocular vision, until an unsuspecting fish swims up to them.  Other Ardeids, such as the snowy egret, forage actively, stirring up the mud with their bright yellow feet and flushing small prey which they then chase down and capture.  In addition to hunting in wetlands, cattle egrets are also known to gather in large flocks around cattle in pastures or behind tractors in agricultural fields, catching any insects flushed by disturbance.  Most impressive of all are the hunting strategies of green herons, which utilize “bait fishing”.  Ecologists have observed these intelligent birds placing insects and seeds on water surfaces to attract fish upwards so that they are easier to catch.

_{Green herons utilize “bait fishing” to catch fish.  Photo credit: David Davies}

During mating season, the exposed skin on most Ardeids’ legs and bills becomes brightly-colored and they grow special plumage (feathers) that drape gracefully from their head and neck.  To attract mates, males will curve their long neck over their back so that their plumes are emphasized, all the while uttering loud calls and snapping their bills.  Once paired, male and female work together to build their nest, incubate their eggs, and feed their young. Of the five species of Ardeids found in Centennial Park, only the green herons build isolated nests; all of these others often nest near each other in noisy, mixed-species colonies high up in groves of trees on the edges of wetlands or rivers. 

It was the combination of colonial nesting and beautiful breeding plumage that almost drove several species of egret to extinction.  Starting in the late 1800s, it became fashionable for women to sport elaborate hats decorated with the breeding plumes of both great and snowy egrets, as well as other birds.  Feather hunters would raid egret nesting colonies, killing parent birds for their plumes and orphaning the young, who, without parental care, quickly perished.  In 1902, one feather supply company alone was estimated to have killed 192,960 egrets at their nests (plus 2-3 times that of their young) in a single breeding season.  Feather hunting was extremely lucrative.  In 1903 egret plumes sold for $32/ounce, making the plumes worth more than twice their weight in gold!

_{Great egrets were hunted almost to the point of extinction in the late 1800s for their beautiful feathers.  Photo credit: David Davies}

Today great egrets and snowy egrets, along with their heron relatives, are once more widespread and common.  Although Centennial Park does not host a nesting colony, you can often see herons and egrets stalking through the shallow wetlands in the Park searching for their prey.

This information has been provided by the City of Vacaville in partnership with the Solano Resource Conservation District.  It was last updated on May 26, 2020.