In June 2009 Diamondback Terrapins at John F. Kennedy Airport made the local, national and international news when they swarmed out of Jamaica Bay and blocked runways for hours. Newscasters loved the cute story of slow-moving turtles bringing the airport to a halt. Newswriters scrambled for information about what was going on, and their reports got pretty ridiculous. We were caught by surprise because even though we have been studying terrapins in Jamaica Bay since 1998, we have always focused our work on Rulers Bar, Jamaica Bay’s largest island. We had felt comfortable mostly ignoring terrapin nesting on the shorelines (like JFK) and the other islands because our surveys showed that there was much less nesting there. In fact, 98 percent of the Jamaica Bay terrapin nesting occurred on Rulers Bar. The east side of the Jamaica Bay shoreline is dominated by JFK Airport, but we mostly ignored it because access was difficult, and we were told there were few terrapins over there anyway.

Some background on the airport might help. JFK Airport construction was started in 1942, on the site of an old golf course and a lot of salt marsh. Eventually, 5,000 acres of Jamaica Bay salt marsh was covered with solid fill. Runway 4 (originally 7,900 feet long) opened June 1949, and was extended (to 11,500) out into Jamaica Bay in the late 1960s. The runway ends on Jo Co Marsh, which is the largest and healthiest salt marsh island remaining in Jamaica Bay.

The first question was whether there really were a lot of terrapins at JFK, or whether a small number were having a big impact. We still don’t have an estimate of the size of the JFK population; however, in 2011 during a three-hour period, 198 terrapins were captured on land at the airport. In comparison, at our Rulers Bar study site where we estimate 1,000 female terrapins nest annually, we encounter 45 terrapins on a peak nesting day. This implies that the JFK Airport population is larger, maybe much larger.

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.

JFK wildlife biologists brought in Dr.Roger Wood and tapped his knowledge on the latest techniques for keeping terrapins off roadways in southern New Jersey. In 2012 airport personnel experimented with corrugated plastic pipe to make flexible temporary barriers to keep terrapins off runways, and in 2013 they expanded these barriers along much of Runway 4L, the most problematic site. This barrier has been pretty successful in keeping the troublesome terrapins out of the news.

An article from The New York Times:

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