Monday, January 12, 2015

Interesting Details on Sanibel's Wading Birds

Though Sanibel is the ultimate destination for shell collectors, it is a highly favored destination for bird watchers as well.

In fact, the island was just recognized as one of the 10 best bird watching sites in the USA.

The number of birds and the variety of birds are easily observed.  Unlike some destinations where binoculars are a necessity to bird sightings so many of our birds, particularly the wading birds,  are large enough to observe with the naked eye and from fairly close ranges.

What is less obvious is the special features that our birds have and use.

The Roseate Spoonbill , possibly the most iconic of all Sanibel feathered residents, is not naturally pink.  It's beautiful pink plumage depends on the Spoonbill's diet.  Shrimp consumption is the primary cause for the pink feathers.  Spoonbills forage by wading in shallow water, swinging their bills from side to side as they wade.  The spoon-shaped bill allows them to easily sift through mud, capturing small fish, crustaceans, and other aquatic animals that are often ignored by larger waders.

Looking at the larger birds like the Spoonbills, Great Blue Herons, Woodstork and other waders one is sometimes surprised to seem them fly off.  They simply look too big to lift up on their own.  But , as they say, looks are deceptive.  All birds have hollow bones, making them much lighter than you would imagine by visual appraisal.  A Great Blue Heron, which can stand 4 feet tall, and catch and eat a fish 15 inches in length,  weighs only five pounds.  Despite its height and girth, the Great Blue is light as a feather....or five pounds worth of feathers.

Another seeming enigma is the habit many waders have of spreading out their wings as they meander through the water.  This is not a show of vanity but a necessity in feeding.  The ability to spread their wings over the water and create a shade enables the waders to see directly into the water and spy their prey.  Similarly, the elaborate neck arching and feather displays made by little  Snowy Egrets and Great Egrets---  also known as common egret, large egret or great white heron----is not to ward off other egrets but rather to attract them.  During the breeding season both males and females develop a delicate cloak of long white feathers that extend over their backs. Courtship displays include erecting their spectacular lacy breeding plumes some raising their wings or arching their necks.

When successful, both parents take turns to incubate the eggs and to feed the chicks. While most birds do not start incubating their eggs until the full clutch is laid, Great Egrets start incubating as soon as the first egg is laid. Thus Great Egret eggs hatch at different times about 25 days later. Great Egret parents also allow their chicks to squabble over food. Chicks often kill each other. Thus, if there is insufficient food, the strongest (usually the one that hatched first) stands a better chance of surviving. Great Egret chicks also have an unfortunate tendency of climbing out of their nests. They then often fall prey to predators. Few chicks therefore survive to fledge, in 6-7 weeks. Great Egrets reach maturity at 2 years and can live for 22 years.

A vacationer interested in birds will have a wonderful time observing our Sanibel flocks and reading more about them!



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