Aside from weather disturbances and runway traffic, New York's JFK Airport has found a rather uncommon reason for flight delays: Turtles.

About 400 diamondback terrapin turtles have been spotted in the airport property this year. These slow-moving animals wander from their Jamaica Bay swampland home to the sandy area near the airport runways, where they build their nests and lay eggs.

The Associated Press reported that while there is no information yet whether an airplane has ever hit a turtle, there were still delays of several minutes as the Port Authority of New York and New Jersey struggled to remove the turtles from harm's way.

After being brought to safety, these turtles were measured, tagged and returned to a safe habitat. But that does not really stop them from coming back.

Usual July hike

This incident is not the first as groups of diamondback terrapin turtles usually make their way from Jamaica Bay to the airport in mid-July after their monthlong mating season.

The airport area has a lot of sandy nesting soil, which is an ideal habitat for the turtles, as per ABC New York.

For several years, it has been a natural behavior for the turtles to lay their eggs near and on the runways, but of course, it seems quite unnatural for the people in the fifth busiest airport in the United States.

In 2014, the airport installed plastic tubings to keep out the turtles, but that did not stop the more adventurous ones to still get in.

And it seems that adventure runs in the blood of these turtles, as the baby turtles--whose nests are placed in cages by terrapin researchers to keep safe from predators--find their own way back to the marsh after they hatch from their eggs.

Why the airport?

But while it is an interesting incident to witness, many people--scientists and researchers included--wonder what lures the diamondback terrapins to the JFK Airport.

A New York Times report in 2014 described a team of scientists who looked into the matter. They discovered that many of the terrapins are young, and in the age where they usually return to the beaches where they were born in order to nest.

The turtle population around Jamaica Bay had also been kept in check by raccoons, which are natural predators of the newborn terrapins. Dr. Russell Burke, a biologist at Hofstra University, hypothesized that something must have happened to the raccoons at JFK several years ago that led to the survival of those eggs that were laid in the area.

In fact, turtle population have increased since 2008, when several raccoons in the Jamaica Bay Wildlife Refuge died due to a distemper outbreak.

Diamondback terrapins (Malaclemys terrapin) are named for the diamond-shaped growth rings on their shell, according to Defenders of Wildlife. They are native to eastern and southern United States.

It is believed to be the only turtle in the world that lives exclusively in brackish water and in habitats like tidal marshes, estuaries and lagoons. However, their preferred nesting sites are sandy beaches.

They are currently listed in the International Union for the Conservation of Nature's Red List in near threatened status, with climate change and habitat destruction as their threats.