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Kahuli at Poamoho
Posted: May 16, 2008
I lead a small group on the Poamoho Trail to look for Kahuli or Oahu Tree Snails. Hawaiian tradition says that kahuli “sing” or “whistle”, but snail biologists say they are unable to make such sounds. The goal of the group was to check out the kahuli’s surroundings for a future trip to record the snails.Â
Kahuli, also known as Pupu Kani Oe (Achatinella sowerbyana) are an endangered species endemic to the island of Oahu with only a few isolated populations left in the wild. Kahuli are active mostly at night. During the day they usually sleep on the underside of leaves. As with our previous hike to see the kahuli at Honouliuli Preserve, we started our adventure in the dark well before daylight so we could reach the snails at first light.Â
Since it rained the night before, the vegetation on Poamoho Ridge was lush, green, and wet — perfect conditions for seeing active snails. A number of ohia lehua trees were blooming with bright red flowers in the stream valley below.Â
Much of the Poamoho Stream Valley is dominated by ohia and koa trees with uluhe ferns growing on the steep slopes of the valley which hold back the forces of erosion.Â
When we reached the section of the trail where the snails live, we were enthralled to see an active kahuli on a rosette of ohia leaves. The shell of the snail was yellow at the base and white at the top with a prominent black stripe that spiraled up the shell to the tip of the cone. Â
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The shell of the snail was about half-an-inch long making this snail a young adult. Full grown adults grow to three-quarters of an inch long. It has been my observation that the shells of full grown adults of this kahuli species (Achatinella sowerbyana) have an additional green section at the base of their shells.Â
During our encounter with this active kahuli, the snail did not sing, whistle, or make any other audible sound. So we continued further up the trail in an attempt to find other active snails.Â
Unfortunately, the sun had risen higher and inched its way over a ridge that once blocked the sun. With sunlight illuminating the landscape, the snails retreated to the underside of leaves to hide and sleep. As a result, none the other snails we saw for the day were active.  Â
Now that we’re familiar with the kahuli’s surroundings, the next step is to return at night in an attempt to record the sounds oral tradition says they make.  Many thanks to the State of Hawaii’s Na Ala Hele program for issuing a permit for us to visit these rare and endangered creatures.