Diamondback terrapins at home in brackish water

While I was reading a newspaper in a mainland airport several weeks ago, a two-sentence news story caught my eye. Flights had been delayed at JFK the previous day, the report said, because turtles were crossing a runway in search of a sandy beach to lay eggs.

Since I was pretty sure that JFK does not host sea turtles, and I didn’t know any other turtles that lay eggs on sand beaches, I thought the reporter got it wrong. But it was I who was wrong.

JFK is located on the edge of a large wildlife refuge called Jamaica Bay, a mixture of salt and fresh water from the Atlantic Ocean and surrounding rivers. The bay is part open water and part intertidal salt marshes that together support 330 species, including birds, fish, insects and a type of turtle called the diamondback terrapin.

This one-of-a-kind turtle is neither a sea turtle nor a land turtle. The diamondback terrapin has the distinction of being the only turtle in North America that lives in brackish waters.

Like many of the world’s estuaries, Jamaica Bay is close to an urban area and, therefore, catches runoff from yards and streets. Fortunately, the bay’s hardy terrapins can tolerate some pollution.

Terrapins are strong swimmers with webbed feet, and the turtles’ shells are so lovely they look like paintings. My favorite photo is on a state of Connecticut environmental protection site: www.ct.gov/dep/cwp/view.asp?A=2723&Q=326000.

Besides being able to live in mildly polluted waters, these turtles also have adaptive appetites. Their strong jaws can crunch up just about anything they come across in the water including fish, worms, snails, clams and crabs. They also eat plants and carrion.

During the winter, diamondback terrapins dig into the mud and hibernate until the weather gets warm. Come spring the turtles emerge, and in June and July they head for sandy beaches to dig holes and lay eight to 12 eggs each.

The incubation period is about the same as that of our green sea turtles. In about 60 days, out pop some of the cutest baby turtles in the world. Hatchlings are about an inch long and patterned like their parents but in brighter colors.

The diamondback terrapin is a small species with females growing to 9 inches long. Males are only 5 inches long.

Their beauty and tasty meat make diamondback terrapins desirable as food sources and as pets. But like most wild animals in the world, these turtles, around the turn of the 20th century, were nearly wiped out by overcollecting. It’s now illegal to take a diamondback from the wild in states along the terrapin’s range, from Massachusetts to Florida and along the Gulf Coast. Still, poaching occurs for the gourmet food and pet trades, and the reptile’s habitat is dwindling.

And then there are the hazards the turtles must face when crossing roads or runways to get to a preferred beach.

At JFK the little turtles get a break. In 2009, after pilots reported turtle traffic on the runway, airport officials shut it down to give wildlife officials time to collect 78 little terrapins slowly making their way across.

On June 29 the runway again closed until about 150 of the determined little nesters got a lift in a pickup truck to the beach of their dreams.

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Reach Susan Scott at www.susanscott.net.