You often hear about how bright artificial lights can affect fledgling seabirds, but did you know they can also disorient newly hatched sea turtles?
Since birds usually navigate to the sea by following the glow of the moon, they can get confused by bright artificial lights at night. They end up circling the light for long periods of time, becoming exhausted and falling to the ground.
"Once they are grounded, they're usually too weak to fly back so it takes them a while, but that's when the threat from dogs or cats and other rodent species can depredate seabird species... or they can get run over by vehicles or never fly back out to the ocean to feed. So they can die from starvation," said U.S. Fish and Wildlife Service biologist Jiny Kim.
Bright lights from houses, streets and stadiums can also disorient baby sea turtles trying to move from the sand to the sea, said Sheldon Plentovich, coordinator for the Pacific Island's Coastal Program for the FWS.
"Sea turtle hatchlings will instinctively move towards the ocean when they emerge from their nest, and the ocean is usually lighted naturally by the stars and the moon. But if hatchlings emerge and they see artificial light sources, like floodlights or housing lights, they'll crawl inland towards those lights where they will die of dehydration — or they will be preyed upon by cat, mongooses, or even invasive ants," Plentovich told Hawaiʻi Public Radio.
"One source of light that people just don't really consider is bonfires — and most often, fires on our beaches are illegal," she said. "We had an incident at Ke Iki Beach Park on the North Shore where hatchling sea turtles were emerging from their nest, and they were crawling straight towards an illegal bonfire."
Sea turtles can even be disoriented by lights miles away, Plentovich said. At James Campbell National Wildlife Refuge in Kahuku, hundreds of newly hatched sea turtles that emerged on a dune died because they went toward a bright white light shining from an inland ridgeline.
The season for both hatchling turtles and fledgling seabirds runs from about July 1 to Dec. 15, so please kōkua and watch out for your lights.
This interview aired on The Conversation on Dec. 14, 2021. The Conversation airs weekdays at 11 a.m. on HPR-1.