So what was special yesterday about the runways of New York City's John F. Kennedy airport that drew over 150 diamondback terrapin turtles to cross its dangerous runways to lay their eggs, delaying flights for hours while wildlife workers took them home? It wasn't the moonlit night or "slow, sweet love," as a spokesperson for the Port Authority of New York and New Jersey told the press. In fact, there was nothing very special going on at all, except that a few JFK pilots happened to be paying attention yesterday, according to conservation biologist Russell Burke of Hofstra University in New York, who studies terrapins in the Jamaica Bay between Brooklyn and Queens. Every mating season, he says, the turtles leave their home and breeding ground in the salt marshes near JFK and take to the nearby sandy, open areas to lay their eggs and bury them in the ground. To a turtle, a runway is just another hurdle on the way to its nursery.
And the invasion isn't over. "They're going to have a trickle of turtles all throughout these next months," says Burke. About 1000 turtles live in the region that he studies; the population near JFK is 10 times that.
Diamondback terrapins, which were overharvested for turtle soup in the early 19th century, have been protected in New York on and off over the past decades. They had been making a comeback for a while, Burke says, but their numbers are now declining again, partly due to the disappearance of salt marsh in the area. The cause is unclear, but rising ocean levels and nitrogen dumped from the New York City sewer system are likely culprits. Another problem is that the terrapin population is very old—and not being replaced. The turtles on the runway yesterday could still be the same individuals that were reported lazing on runways when the airport first opened in the 1940s. "I think of them like the walking dead. There are practically no youngsters," says Burke. The main reason for this: urban raccoons, which also snap up 90% to 100% of the eggs laid by Jamaica Bay terrapins during breeding season.
It's hard to know where turtles fit into the ecosystem of a place like New York City, rife with pollution and a mélange of invasive species. Burke says the importance of turtles is that they serve as a barometer of a wetland's health so many conservation biologists watch their numbers closely.
So what's an airport to do about these slow-moving speed bumps? Burke says that the Port Authority, seeking to avoid more flight delays, has been exploring ideas with his group and others to prevent turtles from crossing the runways. They've discussed building plastic barriers that won't impede planes and can be removed after breeding season. Providing artificial breeding areas closer to the ocean to tempt the turtles away is another option, but the problem, Burke says, is that turtles are creatures of habit and it's really hard to change their minds. "How many neurons does a turtle even have?" he wonders.