Bryan Brillhart Photography Presents Dig Imperial Beach "Bird of the Week", the "Great Blue Heron"
Jun 17, 2016 03:09AM
By Paul Spear
Bryan Brillhart of Bryan Brillhart Photography presents us with the Dig Imperial Beach “Bird of the Week”. This week’s bird is the "Great Blue Heron (Ardea herodias)"The column will provide a picture of a bird(s) locally photographed and we will have background on the bird.
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Great Blue Heron (Ardea herodias)
This week’s “Bird of the Week” is the Great Blue Heron (Ardea herodias), a large wading bird in the heron family Ardeidae. Formerly, they were often shot, simply because it made a conspicuous and easy target, but this rarely occurs today. Colonies may be disrupted by human disturbance, especially early in the season, but they are still common and widespread, and their numbers are probably stable. Northern populations east of the Rockies are migratory, with some going to the Caribbean, Central America, or northern South America. They migrate by day or night, alone or in flocks. Some wander well to the north in late summer. Populations along the Pacific Coast may be permanent residents, even as far north as southeastern Alaska.
Widespread and familiar (though often called a "crane"), they are the largest heron in North America, often seen standing silently along inland rivers or lakeshores, or flying high overhead, with slow wingbeats, its head hunched back onto its shoulders. They are highly adaptable, and thrive around all kinds of waters from subtropical mangrove swamps, to desert rivers, and to the coastline of southern Alaska. With its variable diet it is able to spend the winter farther north than most herons, even in areas where most waters freeze. A form in southern Florida (called "Great White Heron") is slightly larger and entirely white.
Habitat is in marshes, swamps, shores, and tideflats. They are very adaptable, and forage in any kind of calm fresh waters or slow-moving rivers, and also in shallow coastal bays.
Nesting is in trees or shrubs near water, and sometimes on ground in areas free of predators. The "Great White" form is mostly in salt water habitats.
They forage mostly by standing still or walking very slowly in shallow water, waiting for fish to swim near, then striking with rapid thrust of bill. They also forage on shore, from floating objects, and in grassland. They may hunt by day or night.
Diet is highly variable and adaptable, eating mostly fish, but also frogs, salamanders, turtles, snakes, insects, rodents, and birds. They have been seen stalking voles and gophers in fields, capturing rails at the edge of marshes, and eating many species of small waterbirds.
Great blue herons breed in colonies, often of this species alone, but sometimes mixed with other wading birds; and rarely in isolated pairs. Males choose nest sites and display there to attract mates. Displays include stretching their neck up with bill pointing skyward, flying in circles above the colony with neck extended, stretching their neck forward with head and neck feathers erected and then snapping bill shut. Nest sites are highly variable, usually in trees 20-60' above ground or water; sometimes in low shrubs, sometimes on ground (on predator-free islands), or sometimes well above 100' in tree. Nests (built mostly by females, with material gathered mostly by males) are a platform of sticks, sometimes quite large.
After mating, females lay 3-5, sometimes 2-7, pale blue eggs. Incubation is by both sexes, in
about 25-30 days. Both parents feed their young, by regurgitation. Young are capable of flight at about 60 days, and depart their nest at about 65-90 days. Females yield 1 brood per year in the north, and sometimes 2 in the south.
This very large bird is easy to spot. I captured one last week in our own Tijuana Estuary with a crab. While preparing to eat this catch, three black-necked stilts attacked the great blue in an attempt to dislodge the crab for their own devouring (Pictures are attached). Look for these beautiful species and the many others who reside in our Tijuana Estuary while enjoying a leisurely walk on the many trails there. Until next week, Happy birding!