Drawing a Seabird Map

Molokai’s high elevation forests are full of secrets, surprises and rare, native species. Thought to be extinct on Molokai until recently, the endangered Newell’s shearwater, or ‘A’o, is a seabird that may also nest deep in the shelter of Molokai’s forest.

Right now, though, no one knows for sure.

Molokai is home to many native and endangered seabird species but biologists aren’t sure how many or where many of them are nesting. A new mapping project seeks to shed light on the state’s seabird population and represents the first comprehensive survey of Hawaii seabirds to date. Anticipated to last three years, the project is kicking off on Molokai this summer. Scientists from the U.S. Geological Survey (USGS) and the Maui Nui Seabird Recovery Project will be working on the island next week, July 17-21.

The ‘A’o hadn’t been seen on Molokai since 1908, said Molokai biologist Arleone Dibben-Young, and was thought to have died out here. That is, until a few years ago, when one landed several times at One Ali’i Park and Dibben-Young was able to tag it to keep track of the bird.

“To find this bird after so many years [was] really phenomenal,” she said. “That reveals to us that they are nesting in some secret spot on Molokai… Because they nest up in the Forest Reserve in super dense vegetation, you could have a lot and not know it…. We could have way more seabirds here than we thought we have because they’re in places we just can’t get to.”

Hawaiian Petrol. Photo courtesy of Maui Nui Seabird Recovery Project

Seabirds spend most of their lives at sea, usually coming ashore only to breed. Most species return to nest at the same location they were born, according to Jay Penniman, project manager of the Maui Nui Seabird Recovery Project. To figure out whether the ‘A’o and other rare seabirds are nesting in Molokai’s forest, the team of scientists working on the Atlas of Breeding Seabirds of the Main Hawaiian Islands is using acoustic monitors to listen for the presence of seabirds in remote areas.

In early June, they placed automated sound recorders at 11 sites that include known seabird habitats on the islets of Molokai’s north coastline and high in the Forest Reserve, said Jay Penniman, project manager of the Maui Nui Seabird Recovery Project. Using a helicopter to drop the monitors in place, the devices will stay there until August. Once they’re retrieved, again by helicopter, the data on the monitors may give some additional clues into seabird populations and lifestyles.

Penniman said the scientists will listen to the frequency and number of calls on the audio recordings.

“We can’t make direct correlation between number of calls and number of birds but you can pretty obviously tell between a couple birds or a lot,” he explained. Once the team can identify areas with high populations by audio, they can go back and count the number of nests in those areas to come up with more exact numbers.

The acoustic monitors could yield some particularly interesting results.

“Molokai is home to likely a small unknown number of endangered seabirds including the Hawaiian Petrel, Newel’s Shearwater, and Band-rumped Storm Petrel – the first two species likely confined to the most remote portions of the high cloud forest and the storm petrel, if present, in remote cliff areas or on offshore islets along the north and east coast,” said USGS biologist Dr. Josh Adams, one of the Atlas project’s leaders.

The Hawaiian Petrol, or ‛Ua‛u, used to be the most numerous bird in the islands, according to fossil records. They were so many, in fact, that it is said they would darken the sky, said Penniman. But the arrival of humans to Hawaii brought pigs and other animals that destroyed their habitat and preyed on the birds. Like the ‘A’o, the ‘Ua’u were pushed to the mountaintops to nest and are now highly endangered.

Some conversation organizations on the island are working to restore the seabird populations by controlling predators like cats and mongoose and removing invasive species that threaten seabird nesting habitats.

“It’s so appropriate to do seabird restoration on Molokai because fishermen rely on seabird groups to locate schools of fish,” said Dibben-Young. “Different seabirds have different diving styles so you can look at the seabirds and know what kind of fish [are there]…. It’s good for the lifestyle of the island. If we have the seabirds here it’s going to help us find the food to feed our families and the birds will do most of the work for the fishermen.  It ties in so much to subsistence fishing.”

The Bureau of Oceans Energy Management (BOEM) is funding the Atlas project with the goal of understanding more about bird populations in Hawaii and how they would affect potential wind energy projects, particularly offshore.

“Seabirds are one of the major victims of energy development and they want to try to minimize that,” said Penniman. “To do that, we need to learn more about where they forage, where they’re nesting…. [BOEM] is trying to be proactive and having this information before development projects are proposed.”

The Atlas will also provide a valuable tool for continued conservation efforts.

“This work will provide a reference against which to measure future changes in seabird populations and breeding distribution,” stated a USGS press release. “By combining mapped colony locations with recent information about ranging behaviors among birds tracked at sea, we can better evaluate threats to seabirds not only at their colonies, but also far offshore where they fish for food.”

Along with being used to help Polynesian sailors navigate and by fishermen to locate fish, the presence of seabirds historically helped form the Hawaiian Islands themselves, said Penniman, calling them “the original ecological engineers.” Long before vegetation even grew on the islands, seabirds lived here 70 million years ago. They brought marine nutrients to the land, forming the basis of soil. Today, they still perform that function of providing important food to help native plants and ecosystems flourish — a job scientists say could use improvement through the restoration of seabird populations.

When they come to Molokai next week, the team of scientists will be looking for colonies of seabirds of a variety of species on land as well as by boat. They’ll be traveling by boat to survey the island’s northern coastline for nesting areas, spending a night in Kalaupapa and covering Molokai by foot.

The Atlas team will also be collaborating with local organizations that already track seabird populations in specific areas of Molokai.

Dibben-Young has been working with the Molokai Land Trust (MLT) at its Mokio Preserve to monitor seabirds for the last year, establishing baseline numbers based on visual counts. There have been some exciting results following the organization’s removal of kiawe and invasive predators.

Butch Haase, MLT executive director, said for example they have documented return of the kioea, or bristle thighed curlew, for the “first time in modern record” in that area. Haase said fossil records show the species used to be so plentiful on the northwest coastline of Molokai that it was suspected to be the largest concentration of kioea in the Main Hawaiian Islands. Though the kioea is not a seabird, seabird species have also been making Mokio home. Haase said they have roosting sites for ‛Iwa or great frigatebird, and ‘Ā or brown booby. It’s also a document nesting area for Noio, or black noddy, among others.

At The Nature Conservancy’s Mo’omomi Preserve, biologists and volunteers have been monitoring an ever-increasing population of Wedge-tailed Shearwater, or `Ua`u kani, since Dibben-Young discovered the first two nests there in 1999.

But there’s still a lot to learn, and the Atlas project will bring us closer to learning more about Molokai’s seabirds.

“Gathering new information, even basic information about numbers and distribution, will help us make good, informed decisions about land use and ocean activities that can minimize the potential for harm to our shared seabirds,” said Adams. “If cared for, seabirds will always be a part of Molokai.”