It might be time to erect a “Turtles Xing” sign on the runways of JFK Airport in New York. About 100 diamondback terrapins crawled out of the marshes Wednesday morning and started crossing Runway 4 Left, prompting a shutdown for more than an hour. Port Authority specialists had to pick them up and relocate them out of harm’s way. Delays were minor because the runway isn’t used much right now. Why did the turtle cross the road? It’s breeding time, and the reptiles were heading to a sandy spot on the other side of the runway to lay their eggs. A similar thing happened in 2009.