Hawaii's White Terns Thrive in Honolulu's Urban Jungle, Defying Native Bird Decline
In a remarkable display of urban adaptation, a seabird native to Hawaii is flourishing amidst the concrete towers, traffic-clogged roads, and bustling hotels of Honolulu. The white tern, known locally as manu-o-Kū, has seen its population jump more than 50% over the past decade, according to new data, offering a rare conservation success story in a state where many native birds face extinction.
Navigators' Guide and Urban Survivor
For traditional Polynesian navigators like Kaʻiulani Murphy, who guides voyaging canoes across the Pacific using stars, waves, and natural signs, the white tern has long been an indicator of nearby land. These birds hunt at sea and lay eggs on land, making their presence a welcome sight for ocean travelers. "This is our big city," said Murphy, who has navigated to Tahiti, Japan, and Rapa Nui. "It's crazy to me that they're getting to such a big population within Honolulu."
Today, voyagers returning to Honolulu encounter more white terns than at any other time in modern history. The birds are defying the fate of many other native Hawaiian species, which have collapsed due to introduced diseases and predators. As of this week, there are 691 eggs and chicks in Honolulu trees, according to Rich Downs, coordinator of the volunteer organization Hui Manu-o-Kū, named after the Hawaiian term for the bird, meaning "bird of Kū," the god of war.
Urban Habitat and Population Surge
Scientists are intrigued by the white tern's success in an urban environment. Honolulu may be hospitable because human activity has reduced predators like rats and cats around restaurants and buildings, while busy roads deter others. Barn owls and mongoose, which prey on terns, are rare in the urban core. "All the lights and the noise, the commotion of people and traffic, and things like that, doesn't seem to bother them," noted Eric VanderWerf, executive director of Pacific Rim Conservation.
Downtown trees provide favorable habitat, with cup-like scars from trimmed branches offering ideal egg-laying spots. Well-maintained trees thus create plentiful homes. A 2023 survey by Hui Manu-o-Kū, unpublished until now, shows Oahu's breeding adult population has jumped 1.5 times to 3,600 compared to 2016. This growth starkly contrasts with Hawaii's other native birds; since human arrival, 71 of 113 endemic species have gone extinct, with many remaining listed as threatened or endangered.
Unique Breeding and Cultural Significance
White terns are unique seabirds that breed year-round, with peaks from winter into early spring. They do not build nests, instead laying eggs on bare tree branches, cliff ledges, or window sills. After hatching, chicks sit on branches until they can fly, using strong claws to hold on even in storms. Found near islands in warm waters globally, in Hawaii they primarily inhabit remote, uninhabited atolls in the northwest, with Oahu being the only larger island where they've settled.
Not observed breeding on Oahu until 1961, the white tern's population soared in subsequent decades, leading Honolulu to name it the official city bird in 2007. School children now sing songs about the species, and an annual festival celebrates them every May. Volunteers tie blue plastic ribbons around trees hosting eggs to alert trimmers and help bird-watchers track the terns, supported by an online map.
Observation and Symbolism
For eight years, Joyce Hsieh has photographed the birds incubating eggs, feeding young, and raising hatchlings. One of her preferred spots is a Target parking garage, where she drives to the third floor to reach bird-level in nearby trees. White terns, about the same body length as pigeons but with a larger wingspan, fly up to 120 miles from land, feasting on small fish and squid chased to the surface by larger species like tuna.
Murphy, a Native Hawaiian, sees parallels between the birds and her people. Diseases introduced by Europeans in the 1800s killed many Native Hawaiians, but like the resilient white terns, they have adapted and their population is growing. "It's just a special feeling," she said of encountering the birds offshore, likening it to seeing old friends.
This urban success story highlights how some species can thrive in human-altered environments, offering hope for conservation efforts in an era of widespread biodiversity loss.
