Turning out lights keeps seabirds safe from invasive predators
“A t one time there were so many seabirds in Hawaii they blackened the sky,” says Jay Penniman, manager of the Maui Nui Seabird Recovery Project.
Seabirds have been in Hawaii for a long time, first arriving around 70 million years ago. The earliest colonists nested on what’s now known as the Emperor Seamount, the northwestern point of the archipelago that has since eroded below sea level. These ancestral residents mated and reared their young, leaving behind nutrient-rich guano — seabird poop — that helped create soils. Guano nourished and promoted the growth of coral reefs, helping to develop a healthy marine ecosystem. Seeds of flowering plants arrived, sometimes carried in the feathers of the seabirds themselves, and the life on the Hawaiian Islands continued to develop.
As new islands emerged, seabirds continued to colonize them. Some species burrowed into cinder atop Haleakala, others into dunes and the sandy soil along the coastline, still others in the dense tangle of uluhe fern in the rainforest. Isolation led to the evolution of unique species found nowhere else in the world. Clouds of seabirds helped lead Polynesian navigators to Hawaii.
Once numbering in the millions, seabird populations today are a mere fraction of that. Seabirds nest in burrows, on the ground or in the branches of low shrubs. After invasive predators — cats, rats and dogs — began to roam the islands, the adults, young and eggs too often became lunch or worse — killed for play. Young birds that survive to leave their nest face a different threat: artificial lighting.
For millennia, the night sky was lit only by the moon and stars. Fledgling seabirds would leave their burrows after sunset and navigate to sea using the reflection of the moon and starlight on water. Young birds remain at sea for four to five years until they return home to mate and raise their young.
Now, every fall, young seabirds fledge into an illuminated world. Man-made lighting shines into the night from street lamps, porches and stadiums, confusing the inexperienced birds. They may circle for hours until they fall from the sky exhausted. Blueish-hued lights are particularly disorientating. For millennia, the light in the cooler blue wavelength meant schools of myctophids (lantern fish), the bioluminescent prey for the fledgling birds.
Penniman and his team work to tell local residents about the seabirds and respond to reports of downed birds during the fall-out season. One year he was at the Maui Raceway, picking up a petrel that had crash-landed in the back of a pickup truck. As he gathered up the first bird, bystanders saw another one circling lower and lower.
“It fell right at my feet,” says Penniman. “The bird was panting and its heart was racing.”
Although able to wing across thousand of miles of ocean, the fledglings are exhausted and unable to move, making them easy prey for predators and at risk from passing cars.
Recovered birds typically spend the night in a pet carrier, then researchers weigh the bird and place a numbered metal band on its leg. In the light of day, they release the birds at the shore, where they fly out over the ocean to safety. Penniman has been working with these birds for 15 years. Those bands can help tell a happy ending: he’s seen rescued fledglings return as adults, wise now to the distraction of man-made lights.
You can help. If you find a seabird, call 573-BIRD (2473) and someone from the Maui Nui Seabird Recovery Project will come to pick it up. Always keep pets contained and away from seabird colonies. Also, check your lighting. Penniman recommends the following to prevent outside lights from distracting fledgling seabirds:
≤ Lessen the intensity — use the minimum brightness necessary, measured in lumens.
≤ Turn it off — use lights only when needed and consider installing a motion detector.
≤ Point light down, away from the sky. Shields can direct light towards the ground where it’s needed most.
≤ Use warmer temperature, long-wavelength light, above 550 nanometers.
Learn more about seabirds and the Maui Nui Seabird Recovery Project at mauinuisea birds.org.
■ Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. “Kia’i Moku,” “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy and quality of life.