Remember when dozens of mating turtles shut down a whole runaway at JFK International Airport in 2009? It was only the start of a turtle invasion that has vexed travellers and perplexed biologists for years. But we may have figured out why turtles are all over the tarmac, and it has to do with raccoons.
Turtles can be a major hazard on the runway, and they have been responsible for many a delayed flight. Diamondback terrapins crawl into JFK from nearby Jamaica Bay Wildlife Refuge, but they didn't start causing major problems until a few years ago. Airport has since removed hundreds of the turtles and laid down miles of black tubing under the airport's perimeter fence.
Russell Burke of Hofstra University has been working with Port Authority's chief wildlife biologist Laura Francoeur to study the turtle problem since it started. (Yes, airports often have wildlife biologists, but they're usually most occupied with birds.) Their work involves making casts of the shells of turtles they find in JFK. Turtles shells have rings like trees that give away their age. That's when Burke noticed a pattern: the turtles were mostly seven to nine years old. Did something happen seven to nine years ago?
Indeed, in 2008, an outbreak of distemper killed many of the raccoons in the safe wildlife refuge. Raccoons are voracious eaters of turtles -- they usually wipe out 95 per cent of newborn turtle hatchlings. Without raccoons, hypothesizes Burke, the lucky turtles survived to spill out into the airport. An unlucky few, however, have been hit by aeroplanes instead.
Raccoon populations have since recovered, and turtle incidents at JFK have also gone down accordingly. Ultimately, there might not be much to do other than wait. The whole episode reveals how small disturbances in the natural ecology can affect our infrastructures made of concrete and steel -- how a virus in raccoons one year can lead to your delayed flight years later. [New York Times]
Picture: Diamondback terrapin, BS Thurner Hof/Wikimedia Commons