It's approaching four months since my body was wrapped in black neoprene, and I'm getting itchy to descend once more into the magnificent kelp forests of Catalina Island. I may even need a refresher course if I don't remember how to use my SCUBA gear. At least while here in Florida I've kept my video camera running by filming birds and other topside critters near the shores of the Gulf of Mexico. As Steinbeck and Ricketts said, one needs to look from the tidepool to the stars and back to the tidepool again to really understand ecological systems. I've only been looking up during daylight hours as the stars do not provide enough illumination to film!
With all the footage I've captured here of shorebirds, I will be well prepared to edit several episodes about them for my cable TV show. My subject this week will be an albino version of Big Bird... the great egret, known scientifically as Ardea alba (but no relation to that lovely "chick" known as Jessica Alba). This member of the heron and egret family is also known as the common egret, the great white egret or the great white heron (but is no relation to the great white in our waters, respectfully referred to by divers as "the landlord"). My Spanish speaking friends refer to this bird as Garza blanca.
Great egrets tower over most other members in their family at just over three feet. Only the great blue heron is taller. Their wingspan may extend five to seven feet to provide the lift for their "massive" two pound bodies. The long, straight, yellow bill and black legs and feet distinguish them from other related species. Telling the males from the females is difficult since they look alike to untrained eyes like mine, although males are slightly larger.
This species is nearly ubiquitous (scientists refer to them as cosmopolitan, no relation to the magazine) as they are found on every continent except Antarctica. Their distribution is mostly in the tropical and warmer temperate regions of the world. There are different subspecies in Europe, the Americas, Africa and India-SE Asia-Oceana. Here on the U.S. West Coast they are found from southern Canada to Mexico. Like Dr. Bill, this fine feathered friend likes to be near water, although it doesn't care whether it is salt or fresh. They will inhabit swamps, marshes, lagoons, mudflats, lakes, rivers and coastal areas such as beaches, estuaries and tidal flats whereas I prefer to live only on the shores of an ocean... since I am a discriminating marine biologist!
Munching is an important function if an individual critter is going to survive. The great egret feeds primarily in shallow water, but may also gather tasty tidbits from dry land. They are strictly carnivorous (never understood the "moral superiority" displayed by some strict vegetarians). I've observed them diminishing the numbers of my fine finned friends (aka fish) as well as taking small crustaceans such as crabs and fiddler crabs, not to mention frogs in fresh water. They may stand motionless in the water and wait for prey to approach too close, or they may actively stalk it. When in range, they either stab or grab it with their sharp beak.
I've also filmed them wandering through grasslands, alongside shrubbery and even in Mom's garden where they will take small mammals or reptiles, other birds or insects. It is somewhat strange to see these aquatic birds staring up at the leaves of plants instead of down into the water. Dining is usually a solitary activity, usually in early morning or evening... kind of like some of the folks I remember back in my college dining hall (but not Al Gore or Tommy Lee Jones)!
The "other" M word, mating, is critical if the species is to continue. Birds reach sexual maturity at two or three years. As breeding season approaches (spring or summer in temperate regions), these birds develop long ornamental plumes known as "aigrettes" along their back. The male chooses the site and builds a bulky nest of sticks and twigs usually in a tree within a colony of other birds. The male and female are "seasonally monogamous," remaining paired up to raise the kids with both parents sharing child-rearing duties including incubation, feeding and aggressively defending the nest. Clutch size varies from one to six pale blue-green eggs which hatch in three to four weeks. We hear of sibling rivalry among humans, but the stronger, more aggressive young egrets often kill their weaker nest mates. Sheez! The chicks fledge in two to three weeks and can fly in six to seven.
Individuals may Munch all they want and populations Mate all they will, but the individual, the population and the species itself will not survive if faced with unusual mortality. Near the end of the 19th century, large numbers of great egrets were killed for their breeding feathers which then adorned ladies hats. National Geographic reports that the population may have plunged by 95% due to this. The Audubon Society was first established to protect birds like these from such "plume hunters." Thanks to conservation measures implemented over 100 years ago, these majestic birds did not follow the same path as the Dodo bird, passenger pigeon or my love life!
© 2011 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!
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Great egret in creek and waiting on pier for fish to approach; stabbing at fish in creek
and the long white breeding plumes or aigrettes.
This document maintained by
Dr. Bill Bushing.
Material and images © 2011 Star Thrower Educational Multimedia