Herons and egrets are medium to large wading birds, with very long legs and s-shaped necks adapted to their hunting methods.  These tall water birds can be found in almost any wetland habitat.  The Black-crowned Night-Heron forages at night.

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Shorebird trends

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Great Blue Heron
Great Egret
Snowy Egret
Black-crowned Night-Heron


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Great Blue Heron
Ardea herodias


 
Description
One of the most widespread and adaptable herons, the Great Blue Heron is the largest heron in North America.  It has grey upperparts and a grey, black, and white streaked neck.  Legs are brownish or green and bill is yellow.  While flying, neck is curled into an “S” shape. 

Range
Great Blue Herons live year round throughout most of the United States.

Diet
Eats mostly fish, but occasionally rodents, other small mammals, nestlings, and human food scraps.

Natural History Facts
The Great Blue Heron is fairly common year round in Point Reyes.  Throughout the year, the heron makes local movements throughout the area, but does not migrate away from coastal California.  Variations of numbers on Bolinas Lagoon correspond with breeding at Audubon Canyon Ranch. Birds begin breeding in the rookery in late January and the first nestlings are born in mid-March.  Almost half the herons departing the colony have been observed foraging in Bolinas Lagoon.  Fledglings and adults usually leave the rookery around late June and mid-July.  At this time there is a drop in the number of herons on Bolinas Lagoon.  During the summer and fall, herons spend more time in estuaries and lagoons as freshwater habitats dry up.  Great Blue Herons forage in the shallow waters of estuaries, freshwater ponds, marshes, flooded fields, open stream edges, and tidal reefs.  They are also seen feeding in fields on rodents.  

Bolinas Lagoon Population Trends
The number of  wintering Great Blue Herons on Bolinas Lagoon peaked at 15 birds in 1975, then dropped to 6 birds in 1996.  In the past ten years, the population has remained relatively stable, at around 6-8 birds in the lagoon. 

Great Egret
Ardea alba


 
Description
This elegant egret has bright white plumage, long black legs, and a long yellow bill.  During the breeding season, these egrets grow long plumes, which are erected like a fan during courtship displays. 

Range
Lives in freshwater, estuarine, and marine wetlands.  During the winter, the Great Egret can be found throughout the west coast and California to Mexico and Central America.  Great Egrets live year round in the Bay Area, the Central Valley, along the Mexican coasts, and in the southern United States.

Diet
Eats fish, insects, aquatic invertebrates, and small vertebrates including small birds. 

Natural History Facts
Populations were decimated in the 1960s from DDT.  Since the ban of DDT in 1972, clutch and brood sizes have increased. 

Bolinas Lagoon Populations Trends
The number of Great Egrets on Bolinas lagoon during winter increased from only 2 in 1974 to over 10 birds in 1987.  Since 1987, the winter population has decreased and currently there are about 7 Great Egrets on Bolinas Lagoon. 

Snowy Egret
Egretta thula

Description
A slender, medium-sized heron with entirely white plumage, long, slender black bill, black legs, and bright yellow feet.  During the breeding season, the Snowy Egret has long lacy plumes on its head, neck, and back. Young Snowy Egrets are similar to adults, but lack plumes and have yellow stripes up the back of the leg.

Range
Breeds mainly along the coasts south from Oregon and New England, but also at scattered inland areas. Also breeds in the Caribbean into South America.  Winters along the southern coasts of the United States to the West Indies and South America.

Diet
The Snowy Egret has a varied diet including worms, aquatic and terrestrial insects, crabs, shrimp, prawns, crayfish, other crustaceans, snails, freshwater and marine fish, and snakes and lizards.

Natural History Notes
This species uses a greater range of foraging behaviors than any other heron and can be distinguished from Great Egrets by their foraging behavior.  Unlike Great Egrets who stand still waiting to ambush their prey, Snowies can be seen moving quickly through shallow water, using their bright yellow feet to “stir up” or move prey, making them easier to capture.

Bolinas Lagoon Population Trends
Winter numbers on Bolinas Lagoon have increased five-fold from 10 birds in 1972 to over 50 in 2004. 

Black-crowned Night-Heron
Nycticorax nycticorax


 
Description
Usually seen sleeping in bushes or trees during the day, the nocturnal Black-crowned Night-Heron is a stocky short necked bird with a black head and back, gray wings and white underparts.  The bill is black, legs are yellowish or pinkish, and during the breeding season, night-herons have two white plumes on their head. 

Range
Breeds throughout most of the United States and South America and winters along the coast in the southern United States. 

Diet
Black-crowned Night-Herons eat mostly fish but also insects, small mammals, and amphibians.  These herons are also nest predators, feasting on eggs or chicks of other herons, terns and Franklin’s Gulls during the night.  Night-herons are slow, purposeful hunters and can be seen standing motionless for long periods of time before striking a fish or rodent. 

Natural History Notes
Black-crowned Night-Herons are commonly found in the winter and rarely found in the summer on Bolinas Lagoon.  Night-herons roost communally during the day near estuaries, ponds, and marshes, where they feed at night. 

Bolinas Lagoon Population Trends
Black-crowned Night-Heron populations have decreased on Bolinas Lagoon.  In 1976, there was a peak of 24 birds.  From 1986 to 2003, only a few night herons were seen on the lagoon.  In 2004, this number decreased to only one bird.