The once-endangered Hawaiian nene has grown in population due to successful breeding efforts and protection measures, but the pedestrian geese remain highly vulnerable to the hazard of vehicle traffic.

Along with other endemic Hawaiian species, the flightless nene, the only surviving Hawaiian goose, thrived until their natural habitats were destroyed and invasive species such as rats and mongoose preyed upon the geese and their eggs.

The ongoing traffic threat was underscored shortly after midnight Jan. 7 at Maui’s Haleakala National Park when a female nene was discovered killed by a vehicle near the park’s summit entrance station.

Visitors flock to the park’s 10,000-foot crater summit to view spectacular sunrises, but that entails driving up the mountain in darkness. Sunrise reservations for park entry between 3 to 7 a.m. must be made online.

The National Park Service notes that drivers should be aware that wind, rain and poor visibility at the summit can make it hard to spot the brown-and-black geese.

In a press release about the latest nene death, the park service said wildlife biologists observed a lone male goose calling out — believing it to be the dead female’s mate. Nene are currently in the middle of their nesting season, which runs from October to May.

It was the second traffic death of the federally threatened species at Haleakala this nesting season, leading the park service to warn drivers to be careful. The first goose was killed Dec. 23 near the visitor center, just below a flashing nene crossing sign that tells motorists to slowdown and look out for wildlife.

The male was part of one of the park’s first reported nesting pair with goslings in the 2021–2022 nesting season, and the goslings have since died, the park service said. Such ripple effects typically follow the death of a nene parent, Joy Tamayose, NPS wildlife biologist, said in the statement.

“During nesting season, when a nene loses its mate it usually results in total failure for that nene family,” she said, noting, “any goslings that need rearing are likely to perish without both of its nene parents.”

The nene was near extinction and federally classified as endangered after its numbers were reduced to fewer than 30 birds in the wild 50 years ago. It was downlisted to threatened in 2019, after its population had grown to more than 3,000 birds statewide, due to successful breeding and reintroduction efforts, and Endangered Species Act protections.

The birds mate for life, Tamayose said, and “we have observed that nene usually do not find another mate for the remainder of the nesting season.”

To report injured nene or other wildlife in Haleakala National Park, call 808-985-6170.