Fast-growing plant threat to habitat of Lanai petrels

LANAIHALE – For decades, researchers thought the last major colony of Hawaiian petrels in the islands nested on the slopes of Haleakala.

Then about a decade ago, wildlife biologist Fern Duvall was working on Lanai when he noticed a petrel burrow. He kept the discovery in the back of his mind for six years, until he was able to return to the island to follow up.

“We just went to see if we could detect any birds at all,” Duvall said. “It turned out that not only could we find birds – there were thousands of them. We think it’s the second-largest known concentration of Hawaiian petrels.”

Duvall suspects that the birds have thrived on the slopes of Lanaihale – Lanai’s only large mountain – because the island has so little development and few urban lights.

The night-flying birds depend on starlight to navigate and often become disoriented and crash in urbanized areas.

“Lanai disappears after dark,” Duvall said. “We think the birds cue in on this absolute darkness.”

The qualities that attracted the birds to Lanai also helped them go unnoticed for decades – and still makes it tough to get an accurate estimate of the population, said researcher Jay Penniman.