Shearwaters are flocking to Molokai’s Mo‘omomi Preserve
Area has become ‘last stronghold of a coastal dune ecosystem’
The Maui News
The Nature Conservancy’s Mo’omomi Preserve on Molokai is nearing 1,500 active bird nests and more than 3,200 birds — boasting one of the largest and best protected shearwater colonies in the state, according to an announcement Monday.
The 923-acre preserve is the “last stronghold of a coastal dune ecosystem” that has almost disappeared from the main Hawaiian Islands, the Nature Conservancy said. The preserve protects nearly two dozen native plant species, serves as an important nesting site for green sea turtles and was once home to at least 30 bird species — about one-third of which are now extinct.
“Mo’omomi is a very significant colony for the state — it’s now among the largest populations,” said Jay Penniman, project manager of the Maui Nui Seabird Recovery Project. “It’s a shining example of what you can do by just changing the habitat and removing predators. It’s a jewel.”
Efforts began in 1999 after workers discovered two wedge-tailed shearwater nests. The coastal preserve grew as workers cleared acres of invasive weeds and controlled predators.
“The fact that the wedgetails are returning to Mo’omomi tells us that the area is really healthy,” said Wailana Moses, the conservancy shearwater coordinator. “Because the ecosystem is healthy, the species that are supposed to be there are returning.”
Although wedge-tailed shearwaters are not endangered, they have disappeared from many locations in the main islands, the conservancy reported. Shoreline development and predation have driven them from their coastal homes to the safety of offshore islets.
When the two shearwater nests were found in Mo’omomi, it marked the first time in decades.
“We were excited, of course, and the following year we went out there and found 20 nests,” said Ed Misaki, the conservancy’s Molokai program director. “That’s when we decided we should start managing for the shearwaters because they were trying to establish a colony.”
The conservancy faced several challenges in setting up the preserve.
A dense Axis deer population trampled nests and ate the coastal vegetation with roots that supported burrows in the sand, the conservancy said. Loose dogs killed shearwaters in massive numbers, including one night when a single dog killed 70 birds.
Cats were using kiawe thickets as refuges where they brought dead birds to eat them. Mongooses and rats also posed threats.
Workers responded through predator-control programs that pushed back kiawe to create 19 acres of new habitat and built a 1.5-mile coastal fence to keep the animals from returning, the conservancy reported.
The colony’s growth has been tracked annually since 2000, with banding of nesting adults and their chicks starting in 2005.
Banding of adults takes place one night every spring, when the shearwaters return to prepare for the nesting season and to look for or reunite with a mate. Each band is numbered and data are entered into an international database to track species demographics.
In the fall, volunteers return to monitor nesting activity. Then, in late October, they go back to band the shearwater chicks. This October, volunteers banded 239 new chicks.
Wedge-tailed shearwaters, or ‘ua’u kani, are large, dark-brown migratory birds with a black-tipped dark-gray bill, the conservancy said. The birds live most of all their lives at sea and come ashore only to breed, returning to the same nest site each year.
Their return benefits the preserve because their droppings return important marine nutrients to the soil. Plants become far more vigorous, reinstating ecosystem function that has been lost.
Local fishermen know wedgetail shearwaters as the “aku” bird, the conservancy said. Out at sea, schools of akule feed on large schools of bait fish, driving them to the surface. When fishermen see the wedgetails feeding on the bait fish, they know akule are below.
For more information on the Mo’omomi Preserve, visit www.nature.org/ourinitiatives/regions/northamerica/unitedstates/hawaii/placesweprotect/moomomi.xml.