While the Hawaiian islands are home to all kinds of life today, that wasn’t always the case. Apparently, not a single land-dwelling called the islands home 1,500 years ago—only winged insects, one variety of bat, and a vast array of birds had the honor of living on the archipelago.
Many of those endemic birds—roughly 67 percent—have been wiped out of existence since humans first arrived on the islands. Although habitat loss – and more recently, climate change – have played a role in that decline, one especially persistent threat to these native birds have been predatory invasive species, which were introduced – inadvertently or otherwise – to the islands by humans. For example, feral rats stowed away on canoes used by early Polynesian settlers.
In order to protect Hawaii’s native birds from these and other four-legged predators, conservationists at the Kīlauea Point national wildlife refuge on the island of Kauai are trying something new: building a sprawling wall around the birds’ nesting ground.
The state-of-the-art fence stands two meters tall and spans 624 meters (2,050ft) across, creating a physical barrier that blocks invasive predators from accessing nesting seabirds and their young. The fence is capped with a rolled hood to stop attempts of climbing over, and an underground extension of its base wards off predators who can burrow and dig. The fence – with its very fine mesh – can prevent anything “larger than a one-day-old mouse” from getting through, according to the US Fish and Wildlife Service. The fence is also composed of marine-grade stainless steel to withstand natural disasters.
While the barrier is designed to protect the seabirds from bodily harm, the wildlife refuge ultimately wants the birds to thrive – which necessitates a large number of ongoing side projects. One is habitat restoration – just as predatory mammals are catastrophic to Hawaii’s birds, invasive plants have crowded the islands, choking out native flora that can be used as a food source for Kauai’s birds.
Each year, the Nihoku project transforms one acre of the wilderness refuge, uprooting all introduced vegetation and replacing it with native species. Volunteers also build artificial burrows, which provide the birds with reliable shelter. The Nihoku project is also working to attract animals to Kīlauea Point. Seabird calls are broadcast from a large speaker to attract the attention of adult birds, while volunteers search for hatchlings.
Although Hawaii’s gradual loss of biodiversity is tragic, initiatives like this one give hope of a brighter future for these beautiful islands.