Airline passengers flying from and to JFK Airport faced some delays when dozens of turtles decided to leave Jamaica Bay and take to the runways. Why? To lay eggs on the other side.

On Friday afternoon, flights had to wait for the diamondback terrapins to do their thing. One person Tweeted, "Im taxiing in my plane because there are turtles on the runway. Perhaps the only excuse I have ever found endearing," while another described, "My @AmericanAir flight into JFK is apparently delayed due to dozens of turtles crawling out of the bay onto the airfield."

A Port Authority spokesperson told the Daily News, "There were planes briefly stuck in queue,. It is turtle season here, but it was a little unusual to get the turtles at this time."

This part of the turtles' mating ritual has been happening for years. "Rather than lay their eggs in peace on a quiet beach as the hard-shelled creatures in other parts of the world do, these New York turtles opt for the sand that lines the airport perimeter," DNAinfo explained last year. The Jamaica Bay Terrapin Research group tried to get down to the bottom of the phenomenon:

Where did all these terrapins come from? Like many major airports, JFK has a full-time team of wildlife biologists who have traditionally focused their attention on bird and mammal hazards to aircraft safety. Trained people were in the right place at the right time to have seen terrapins on land in large numbers in the years before the 2009 eruption, and their failure to see many terrapins probably means the number of terrapins in those days was small. JFK wildlife biologists have marked 2,426 terrapins so far, scanned each one first for our microchips and have found none. We have not detected a decline in the Rulers Bar population. Also, the airport is about 2.8 miles east of Rulers Bar, which is farther than terrapins normally roam.

Finally, the airport terrapin population might have grown tremendously in the last 10 years, perhaps due to a drop in egg predation by their main nest predator, raccoons. This is the most likely explanation, although we do not know why the raccoon population would have decreased then.

In 2013, the Port Authority installed plastic tubing to act as a barrier, leading to a nearly 50% drop in turtles on the airfield. But it turns out those barriers are underwater during high tide...