Herons and Egrets in the Silicon Valley

Caitlin Dempsey

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Walk along any lake or pond at any of the many open space areas found in the Silicon Valley and you are bound to see a variety of shorebirds. Despite being a hub for the technological space, open space is widespread in the greater San Francisco Bay Area. County parks as well as local agencies like Midpeninsula Regional Open Space District (70,000 acres) and Santa Clara Valley Open Space Authority (28,000 acres) protected natural land while offering recreational areas across the Silicon Valley area.

The many lakes, ponds, and creeks in these parks and preserves host a wide range of waterfowl. Ducks, geese, cormorants, and scoters are common birds you might expect to see during a visit.

Common herons and egrets in the Silicon Valley

Herons and egrets, with their graceful silhouettes and poised hunting stances, often stand out among these water birds. The diverse habitats of Silicon Valley, including its wetlands, rivers, and estuaries, provide ideal environments for these birds.

Locations such as Don Edwards San Francisco Bay National Wildlife Refuge, Alviso Marina County Park, and the Palo Alto Baylands Nature Preserve are well-known locations for birders to observe herons and egrets in their natural habitat in the Silicon Valley area. Vasona Lake County Park in Santa Clara County is another location with an ample presence of herons and egrets.

Herons and egrets play a significant role in the ecosystem as both predators and indicators of environmental health. As top predators in their food chain, these birds help to control the population of fish and insects. The presence and health of these birds are often are indicators of the quality of the water and the overall health of the ecosystem.

Great Blue Heron (Ardea herodias)

The Great Blue Heron is one of the tallest easily recognizable water birds in Silicon Valley. Standing up to four feet tall, with a wingspan of nearly six feet, these birds are known for their blue-gray plumage, slim build, long legs, and sinuous necks.

Great Blue Herons frequent both freshwater and saltwater habitats, often seen standing motionless in shallow waters waiting to spear fish with their sharp beaks. Great Blue Herons will also prowl in grassy areas to hunt. In addtion to fish, blue herons have a diverse diet which includes amphibians, reptiles, invertebrates, and small mammals, as well as occasionally preying on small birds.

Great Blue Herons nest in tall trees and form breeding colonies known as heronries.

A tall blue and white water bird stands in the water.
Blue heron are among the tallest birds seen at water bodies in the Silicon Valley. Photo: Caitlin Dempsey.

Great Egret (Ardea alba)

Similar in size to the Great Blue Heron, the Great Egret is distinguished by its all-white plumage and yellow bill. During breeding season, they develop long, ornate feathers known as aigrettes. These birds are often spotted along the marshes and riverbanks of Silicon Valley, hunting for fish, frogs, and insects.

A large white water bird hunting in the grass.
A great egret hunting in the grass at Martial Cottle Park in San Jose. Photo: Caitlin Dempsey.

Historically, the Great Egret faced significant threats due to the demand for their aigrettes in the fashion industry, leading to their near extinction. Conservation efforts in the early 20th century helped recover their populations.

Snowy Egret (Egretta thula)

Smaller than its great counterparts, the Snowy Egret is a delicate bird with pure white feathers, black legs, and distinctive yellow feet, often described as “golden slippers.” They are a common sight in the shallow waters and mudflats of the Bay Area.

Agile hunters, they use their feet to stir up prey before swiftly catching it. The Snowy Egret, like the Great Egret, also faced a decline due to the plume trade but has since rebounded.

Green Heron (Butorides virescens)

The Green Heron is a small, stocky bird with a richly colored plumage of green and chestnut. Unlike its larger relatives, the Green Heron is more secretive, often hidden among vegetation near water bodies. Green are known for their remarkable fishing technique, using bait such as insects or small objects to lure fish.

Black-crowned Night Heron (Nycticorax nycticorax)

The Black-crowned Night Heron is in size than a Green Heron but smaller and more robust in build compared to a Great Egret. This heron has a stocky build with a short neck and legs, which gives it a somewhat stout appearance compared to the more slender profile of other herons and egrets.

While most herons and egrets are active during the day, Black-crowned Night Herons forage primarily at night or during the early evening and morning hours. Their diet is varied, including fish, crustaceans, insects, small mammals, amphibians, and occasionally other birds.

A blue and white water bird with large yellow feet among the reeds.
A black-crowned night heron hunts in the reeds at Vasona Lake. Photo: Caitlin Dempsey.

Black-crowned Night Herons are commonly found in a variety of wetland environments including marshes, riversides, lakes, and estuaries in Silicon Valley. These heron are adaptable and can even be found in urban parks like Vasona Lake in Los Gatos and in residential areas near water bodies.

References

Egrets and Herons of Shorebird way. (n.d.). Santa Clara Valley Audubon Society. https://scvas.org/shorebird-way

Heron and egret atlas for the Bay Area. (2012, July 20). Bay Nature. https://baynature.org/article/heron-and-egret-atlas-for-the-bay-area/

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About the author
Caitlin Dempsey
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.

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