Approximately every thirteen hours, low tide turns the marsh on Wilmington Island, Georgia, into a vast expanse of what first looks like nothing but mud and grass. On closer inspection, the mud is riddled with holes and crawling with tiny crabs the exact color of the mud. The crabs are many, well-camouflaged, and in such constant motion on the surface of the mud, it looks like it's boiling. They're all over the boardwalk, too---on it, under it, and between the slats. At first it seems impossible to avoid stepping on them, but they scurry fast at the last second before footfall. No wonder the green herons and the egrets, both great and snowy, hang around at low tide. And no wonder they wait so still and long. It requires a swift silent stab to surprise a crab. (No rhyme intended, but I'll take it :-) These crabs are about the size of a nickel, gifted at eluding shoe or camera, and don't stand a chance against beak of egret.
(See comment from Mike B. on my last post re: the blood vessels in the egret's neck when it so stabs---and while you're at it, check out Mike's blog---some amazing nature photography. You can get to it by clicking on his name in the comment box.)
High tide comes about six and a half hours later, when the marsh fills with water deep enough for kids and dogs to splash in. It was about waist high the day I saw two young brothers having high adventure hiding from each other in the tall grass. I kept thinking about the crabs under their feet, and had to ask their father. They wore special shoes, he said, and the "mud" is not actually mud. It's fairly solid clay which explains why the water was remarkably unmuddy, even where the boys stirred it up.
Ordinary high tide on Wilmington Island looks like this from the boardwalk:
Enter Hurricane Irene---well, more like pass at a safe distance--- but close enough to make herself known. Nobody played in the high tide that came with Irene. The storm was intense, if short-lived. The trees whirled. Massive sheets of rain whipped over the marsh. The lights went out. It came and went in less than an hour, followed by the proverbial calm after the storm. But the power stayed off and the water crept higher, until the marsh looked more like a lake.
Here's Irene's high tide, taken from about the same spot on the boardwalk:
By the time the water got to within ten yards of the house, I became a bit concerned, but like the crabs, it reversed its direction in the nick of time. This shot is from the deck on the back of the house:
Unlike the crabs, it retreated slowly. Within another six hours came the mysterious hollow popping sounds I've heard before at low tide. I think it's the crab holes opening up as the water drains back to the ocean. I'll ask three locals and let you know what I find out. dkm
Tomorrow: John Muir, on the eternal grand show of nature.