The path in the photo on the right is a sidewalk, leading to the Kilauea Lighthouse on Kauai. It is also a runway for coming and going wedge-tailed shearwater seabirds. When the white markings start appearing in early spring, we know the wedge-tailed shearwater have returned from their wintering grounds of Central America.
Wedge-tailed shearwater breed and nest on the main Hawaiian Islands and the Northwestern Hawaiian Islands, now known as Papahanaumokuakea Marine National Monument. Because the refuge opens at 10:00 and closes at 4:00, we rarely see the adult birds when they’re here. They come and go at dawn and dusk, spending their days fishing at sea. What’s amazing is these moderately-sized seabirds, with a three-foot swingspan, will plunge deep into the ocean for food and even swim after their prey. Their feet are set far back on the body, making them adept swimmers but not so agile walkers. That’s why they like to nest on cliffsides.
Speaking of their nestsites, wedge-tailed shearwater dig burrows as deep at seven feet for the one egg they will lay. While we rarely see them during the day, sometimes we hear them. Their courtship include lots of moaning and groaning. They sound just like an injured hiker would if they’d fallen over the side of a cliff.
After 52 days of constant incubation by both parents, the tan-colored egg hatches. These fuzzy balls started appearing on the refuge in August. Usually grey, we have one near the entrance of the visitor center that is pure white. It’ll be fun to watch this one grow. I’ll try to get a picture for you.
One of the more interesting facts about these birds–as well as all the marine birds at the refuge–is that they act like they’re tame. They nest a few feet off the edge of the sidewalk and don’t mind our presence one bit. The reason, I’m told, is they evolved in predator-free zones. Take Hawaii. The island state boasts only two native mammals: The Hawaiian monk seal and the hoary bat. Neither feasts on seabirds. Sure, there is a rare chance an opportunistic shark may snare a wedge-tailed shearwater if the shark just happens to be cruising by when the bird dives into the water to fetch its dinner. That’s probably more rare even than our own chance of a shark encounter. Certainly more rare than our chance of getting struck by lightening. These days, however, the biggest threat to Hawaii’s seabirds on land are rats, cats and dogs. At sea, marine debris and longline fishing drown birds every year. All of these are real threats. In May, almost 90 wedge-tailed shearwater were slaughtered, most likely by a pack of dogs, at Kahuku Golf Course on Oahu.
The chicks will spend the first 90 to 100 days of their lives with us at the refuge before they fledge, flying out to sea. I’ll keep you posted with photo updates for the next couple months.