Home > Islets > Niihau > Lehua ISLETS: NIIHAU > LEHUA Lehua   Lehua - Photo: E VanderWerf Lehua - Photo: C Swenson   Lehua - Photo: D Boynton Lehua - Photo: K Wood   Lehua - Photo: K Wood Physical Features Lehua is a tuff crater located 1/2 mile north of Niihau and roughly 18 miles west of Kauai. The underwater volcanic eruption that formed Lehua is similar to the one that created Kaula, accounting for their similar appearance. Subsequent erosion by waves, wind and rain shaped its current crescent-shaped appearance, wave-cut benches, and numerous eroded valleys. The largest of Hawaii’s offshore islets, Lehua is 290 acres in size and 702 feet at the highest point. It is more than twice the size of Kaula. Several sea caves are present on Lehua, including Anakukaiaiki which is home to Kukaiaiki, son of the shark god Kuhaimoana. Regulations Landing requires permission from the U.S. Coast Guard. Activities on Lehua are also subject to Hawaii Department of Land and Natural Resources regulations for State Seabird Sanctuaries. Disturbance of seabirds and other wildlife within the sanctuary is forbidden. Federal law also protects seabirds, shorebirds, and threatened or endangered species. Birds Lehua stands out for the number and diversity of its breeding seabirds, as well as the presence of rare seabird species found few other places in Hawaii. Recent surveys documented over 25,000 breeding pairs of seabirds and up to 11 species nesting or attempting to nest on Lehua. Wedge-tailed shearwaters are the most numerous species on the island, but Lehua has the largest Brown booby (Sula leucogaster) colony and one of the two largest Red-footed booby (Sula sula) colonies in Hawaii (including the Northwestern Hawaiian Islands). Lehua and nearby Kaula are the only two nesting locations in the Main Hawaiian Islands for rare Black-footed albatross, which were first documented nesting on Lehua in 2001. Laysan albatross, another species rarely seen in the main Hawaiian Islands, also nest on Lehua. Another exciting discovery was the presence of rare Band-rumped storm petrels (Oceanodroma castro) and Newell’s shearwater (Puffinus auricularis newelli). The latter, listed as threatened under the U.S. Endangered Species Act, was recently seen circling Lehua in the evening. Biologists also found the body of a juvenile too young to fly, demonstrating that this rare and declining species is attempting to nest on Lehua. The presence of rats makes it difficult for this and other small seabird species to nest successfully. Plants Like its sister islet Kaula, Lehua often goes for long periods without rainfall, causing much of the vegetation to dry out. During the rainy winter months, the vegetation reappears. Rabbits and rats introduced over 70 years ago severely altered the islet's ecosystem. The activity of these introduced species decimated native plant populations and allowed alien species to dominate. Even so, twenty-two species of native plants (13 indigenous, 9 endemic) persist on the islet today, mostly in small numbers. However, a native morning glory vine is one of the most common plants, likely because rabbits found it unpalatable. The eradication of rabbits in 2005 could cause major shifts in vegetation patterns and a monitoring program is in place to track these changes. Insects The first recorded insect collections on Lehua were made between 2001 and 2006. Over 60 insect species were collected, including 11 native endemic species found only in Hawaii. However, most species collected were aliens. Because Lehua is fairly large, additional insect collections using a wider variety of collecting techniques would certainly expand the species list. One of the most potentially harmful alien insects on Lehua is the Big-headed ant (Pheidole megacephala). These occur in large numbers and are suspected to prey upon native insects, plant seeds, and potentially seabird chicks. Another potentially harmful alien on Lehua is the grasshopper species (Schistocerca nitens) which recently ate much of the native vegetation on Nihoa Island. Marine Organisms The waters surrounding Lehua support a diverse marine biota, including a healthy shark population. Researchers have documented great white sharks from California in waters around Lehua and Niihau. Dolphins, whales, sea turtles, and manta rays are often seen swimming through the channel between Lehua and Niihau. Hawaiian monk seals commonly haul out to rest on the rocky ledges around Lehua. Bishop Museum, NOAA and the State of Hawaii conducted a joint marine survey in July 2006. Survey results are not yet available. Human Uses The frequent mention of Lehua in Hawaiian oral traditions shows that they were well aware of its existence. Although there is no evidence of any permanent settlements, stone structures are present on Lehua and Hawaiians likely visited to fish and to harvest seabirds, feathers and eggs. The federal government built a lighthouse on Lehua in 1932 that was replaced by a solar powered light in 1989. The waters around Lehua are visited regularly by a small number of fishermen, dive boats, bird watchers and other sightseers. Threats When the first biologists visited Lehua in 1931, Polynesian rats and Rabbits (Oryctolagus cuniculus) had already been introduced. Rats eat many native species of plants, insect, seabirds, and intertidal invertebrates. They are a major threat to island ecosystems and plans are currently underway to eradicate them from Lehua. Rabbits were extirpated in 2005 in order to allow native vegetation to grow back. The resulting increase in plant cover is expected to stabilize soils and reduce runoff of sediments into the ocean. Other threats include a variety of invasive weeds and insects, including four species of alien ants. Seabirds are also vulnerable to being eaten by introduced Barn owls (Tyto alba) that regularly visit Lehua. > Back to top of page Home  Islets  Species  Projects  Outreach  Links  About Us