HONOLULU (AP) — Kaʻiulani Murphy, a traditional Polynesian navigator, readily identifies white terns during her voyages across the Pacific Ocean. For navigators like her, the presence of these birds—which forage at sea and nest on land—signals proximity to land.

Urban Adaptation: A Growing Population

Recently, voyagers returning to Honolulu have observed more white terns than ever before in modern history. New data reveals a population increase of over 50% in the past decade, demonstrating the seabirds’ ability to flourish amidst the city’s infrastructure.

A Resilient Species

This success story contrasts sharply with the fate of many other native Hawaiian birds, which have suffered population collapses due to introduced diseases and predators. “This is our big city,” said Murphy, who has navigated canoes to destinations like Tahiti, Japan, and Rapa Nui. “It’s crazy to me that they’re getting to such a big population within Honolulu.”

Monitoring and Conservation Efforts

As of this week, 691 eggs and chicks were recorded in Honolulu trees, according to Rich Downs, coordinator of Hui Manu-o-Kū, a volunteer organization named after the Hawaiian name for the white tern, meaning “bird of Kū,” the god of war. The birds breed year-round, with peak activity from winter into early spring.

Unlike most seabirds, manu-o-Kū do not build nests, instead laying their eggs directly on bare tree branches, cliff ledges, or even window sills. Their strong claws allow hatchlings to cling to branches, even during storms.

Unique Habitat Preferences

While found near islands in warm waters globally, in Hawaii, they primarily inhabit remote atolls. Surprisingly, they’ve established a breeding population on Oahu, home to 1 million people.

Reasons for Success Remain a Mystery

Scientists are still investigating why the birds are thriving in Honolulu. The urban environment may be beneficial due to reduced predator populations—rats and cats are less common near restaurants and buildings—and busy roads deter predators like barn owls and mongoose.

“All the lights and the noise, the commotion of people and traffic, and things like that, doesn’t seem to bother them,” said Eric VanderWerf, executive director of Pacific Rim Conservation. Well-maintained trees, with scar tissue creating cup-like formations, provide ideal nesting spots.

A Stark Contrast to Other Hawaiian Birds

A 2023 population survey by Hui Manu-o-Kū, recently published, showed Oahu’s breeding adult population increased 1.5 times to 3,600 compared to 2016. This contrasts with the broader trend in Hawaii, where 71 of 113 native bird species have gone extinct since human arrival. Remaining species are often threatened or endangered.

While native to the islands, manu-o-Kū were first observed breeding on Oahu in 1961. Honolulu officially named the bird its official bird in 2007, and it is now celebrated through songs and an annual festival. Volunteers mark trees with ribbons to protect nests during trimming. Photographers like Joyce Hsieh document the birds’ life cycle.

Kaʻiulani Murphy, the Native Hawaiian voyager, draws parallels between the resilience of the manu-o-Kū and her own people, both having overcome challenges to thrive.