Now that rats are eradicated at Palmyra Atoll, seabird ‘discotheques,’ decoys result in chick

A tiny grey-backed tern chick has been observed at Palmyra Atoll, validating that seabird attraction efforts are working, according to The Nature Conservancy of Hawai‘i and Palmyra.

This bird is one of eight seabird species known to the region, but it has been conspicuously absent from the atoll, likely due to invasive rats that were introduced during the World War II era.

In 2011, rats were successfully eradicated from Palmyra Atoll and in 2020 scientists began deploying social attraction techniques including wooden seabird decoys mimicking colonies and “seabird discotheques” that play the calls 24/7 of the eight absent seabirds.

“It is very exciting to observe this grey-backed tern chick at Palmyra,” said Hannah Martin, The Nature Conservancy Palmyra Conservation Science Volunteer. “An important part of our work as science volunteers at Palmyra is to maintain the social attraction sites and record observations or indications of the seabirds we’re trying to attract back to Palmyra. It’s very rewarding to see a first indicator of success.”

Grey-backed terns, or Pākalakala in Hawaiian, are found in Hawai‘i and other remote islands across the Pacific. While they are not endangered, they are especially vulnerable to invasive predators bacause they lay a single egg per season. They feed on small fish and squid.

“The discovery of this chick is very exciting because it signals we are moving in the right direction with our seabird restoration efforts at Palmyra,” said Katie Franklin, Palmyra Island Conservation Strategy Lead. “We are collaborating with the U.S. Fish and Wildlife Service to enhance Palmyra’s seabird habitat and maintain social attraction sites across the atoll to encourage seabirds extirpated from the atoll to come home and settle down.”

Approximately 30% of seabirds are endangered, making them one of the most threatened bird groups on the planet. They play a vital role in island ecosystems — their guano provides nutrients for plants and trees on land and directly increases the health and resilience of coral reefs and fish.