Looking Back by Looking Down
Ancient sinkholes formed over millennia hold the secrets to the islands’ earliest residents.
Wrapped around by a rusty chain link fence, flown over by a coal conveyor and wedged amongst the engines of our economic future in the Campbell Industrial Complex may be the most important link to our evolutionary past: THE ALAN ZIEGLER PRESERVE.
Never heard of it? Few have, but this six-acre lot was set aside by the Kapolei Property Development in August of 2008 to maintain some of the last remaining sinkholes that once covered the ‘Ewa Plain.
In general, sinkholes are created over centuries as the acidity of rainwater eats away at the limestone, causing underground caverns to form and eventually give way to the weight of the earth above them.
Here in Kapolei, anyone who has ever put a shovel in the ground knows that the entire plain is made up of an ancient reef that dried up as ocean waters receded 120,000 years ago. This weathered karst, as it is known, is a limestone substrate that through the centuries was eaten away by the rains creating thousands of vertical bell-shaped caves or sinkholes.
While they are—geologically speaking—of some interest, their true value comes from their unintended ability to serve as a trap for animals. Due to their vertical nature, once a creature found itself in such a place, there was little chance of escape as scaling the walls was impossible and rare is the bird that can hover straight up like a helicopter to escape these narrow confines.
So what we had was a perfect repository to collect fossils of the wildlife that occupied these islands long before the Polynesians ever set foot on this volcanic chain.
Unfortunately, 99 percent of these “fossil tombs” have either been bulldozed for agricultural lands, lain over with concrete for development or simply lost to the ever-shifting sands of time, which brings us back to our little six-acre plot in Kapolei.
They were first discovered in the 1970s by Jennie Peterson, an archaeologist with Bishop Museum, as she was doing an environmental impact study on the once-proposed Deep Draft Harbor, but the history of the sinkholes would be written by local zoologist Dr.
Alan Ziegler who spent decades exploring, documenting and teaching others about the wonders to be found out here on the Plain.
Eventually, the Smithsonian got involved with the project and the preeminent avian paleontologists Storrs Olson and Helen James came in to examine the remains.
What they found was astounding. More than 40 extinct species were interned in the sinkholes and of whose existence no one had known until they were discovered here.
There were remains of sea eagles and hawks, flightless rails and finches, and most shocking of all the moa nalo, which in Hawaiian means “lost fowl.” It was a three-foot tall flightless goose-like duck with a head like a tortoise. Many of the remains were in articulated form, as they had most likely died in the sinkhole after having fallen in, giving scientists an unadulterated look into our distant past.
“Back in the day, with all these birds, it must have been quite a raucous place!” says Marjorie Ziegler, daughter of Alan and executive director for the Conservation Council for Hawai‘i who hopes to oversee the care of the preserve one day.
Many of these remains now reside in Washington, D.C. at the Smithsonian and while the important artifacts have been removed, there is still much for future generations to learn at this holdover from pre-human contact Hawai‘i.
For years the CCH and Hawai‘i Nature Center led tours to the sinkholes, allowing children a chance to play archaeologists for a day. Ladders would be set up, many of the holes are 8-feet deep, and the kids would descend into the depths to use trawls, scoop sand and bring buckets of it to the surface.
Here they would use screens to discover the bones of Hawaiian petryls, the ‘ua‘u, that is only found on neighbor islands now and the beaks of long-gone crows who used to call O‘ahu home. They would always return the remains to the sinkhole to allow the next group to discover them.
But in recent years, invasive species of plants have overgrown the property, the holes are obscured by weeds making it difficult to find them or, even worse, hard to see their openings until you are falling into one.
The sea air and vandals have ravaged the fencing; and while still protected on paper, Ziegler is concerned about what could happen to this valuable natural resource.
“I worry less about homeless people setting up camp in there than about the accidental bulldozer collapsing them,” says Ziegler.
The holdup on the turnover of the land to the DLNR is a modern-world one.
The property cannot be conveyed until the surrounding land is subdivided and the subdivision cannot happen until there is improved road access to the surrounding industrial park development. This development, named Kapolei Harborside is planned to happen over the next decade, so while the plan is still to turn the land over to the DLNR, it may be some time before the public gets to visit this important bit of our area’s history.
When this lot at the corner of Malakole and Hanua streets is officially turned over, Ziegler and her team at CCH have big plans for the sinkholes starting with clearing the land of all the invasive species, including many large kiawe trees, and marking the sinks so that the visitors can be safe when visiting.
Next will be to build an educational area where kupuna can talk about these extinct species before kids go visit the sinkholes. And here, Ziegler’s visions can finally be realized, as amongst the remains our ancient past, the minds of our future can grow.
For more on the Conservation Council for Hawai‘i, log on to www.conservehi.org