HONOLULU — The Manu-o-Kū, or white tern, a seabird native to Hawaii, is flourishing in the heart of Honolulu’s bustling cityscape. This remarkable success story contrasts sharply with the struggles faced by many other native bird species in the Hawaiian Islands.

A Growing Population

New data reveals a significant increase in the white tern population, jumping more than 50% in the past decade. As of this week, 691 eggs and chicks were observed in Honolulu trees, marking the highest number recorded in modern history. The breeding adult population on Oahu has risen to 3,600, a 1.5-fold increase since 2016.

A Sign of Land for Navigators

Kaʻiulani Murphy, a traditional navigator and Honolulu Community College professor, notes the significance of the white terns. Like other Polynesian voyagers who rely on natural cues, she views the birds’ presence as an indicator of nearby land. “This is our big city,” Murphy said, expressing her surprise at the species’ ability to thrive within Honolulu’s urban environment.

Unique Breeding Habits

The Manu-o-Kū exhibit unique breeding behaviors. Unlike most seabirds, they do not build nests, instead laying their eggs directly on bare tree branches, cliff ledges, or even window sills. Hatchlings cling to branches with strong claws until they are ready to fly. They are found in warm waters around the world, but in Hawaii, they primarily inhabit remote atolls, with Oahu being the only major island where they breed.

Why Honolulu?

Scientists are still investigating the reasons behind the white terns’ success in Honolulu. Possible factors include reduced predator populations – like rats and cats – near human activity, and the deterrent effect of busy roads. Well-maintained trees with trimmed branches also provide ideal egg-laying spots.

Eric VanderWerf, executive director of Pacific Rim Conservation, notes, “All the lights and the noise, the commotion of people and traffic, and things like that, doesn’t seem to bother them.”

A Contrast to Other Hawaiian Birds

The white tern’s thriving population stands in stark contrast to the fate of many other native Hawaiian birds. Since human arrival, 71 of 113 bird species unique to the islands have gone extinct. Remaining species are often threatened or endangered, found in small numbers in higher elevation forests.

Community Support

The Manu-o-Kū was officially named Honolulu’s bird in 2007, and is celebrated through songs and an annual festival. The volunteer organization Hui Manu-o-Kū, whose name comes from the Hawaiian name for the white tern, ties blue ribbons around trees hosting eggs and chicks to alert tree trimmers. Birdwatchers also use the ribbons to track the population.

For eight years, Joyce Hsieh has documented the birds’ life cycle through photography, even finding vantage points in parking garages to observe nesting sites.

Murphy, a Native Hawaiian, draws parallels between the resilience of the Manu-o-Kū and her own people, both having overcome significant challenges to survive and thrive.