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Location USA, Hawaii
Central coordinates 160o 0.08' West  22o 0.02' North
IBA criteria A1, A4ii, A4iii
Area 117 ha
Altitude 0 - 213m
Year of IBA assessment 2009

Audubon



Site description Lehua Islet is a small, rocky, volcanic island 1.2 kilometers north of Niihau and 31 kilometers west of Kauai. The volcanic tuff crater that formed Lehua 4.9 million years ago is now highly eroded and nearly half submerged, forming a steep, crescent-shaped island with an area of 117 hectares, a length of 2 kilometers, and a maximum elevation of 213 meters. The upper slopes of the inner crescent are composed of parallel strata that have eroded at different rates, producing a series of weathered ledges 1-2 meters wide and 1-2 meters high. The lower slopes of the inner crescent are eroded into chasms and fissures. The outer slopes are smoother, but have several eroded gullies that widen near the shore. Cliffs up to 55 meters high occur on the eastern and western points. The shoreline is rocky and often washed by large waves, especially in the winter. Lehua is in the rain shadow of Kauai and is very dry, especially during the heat of summer. Much of the island is bare rock, eroded sediment has collected only in gully bottoms, ledges, and small caves. Vegetation is sparse but many plants have a growth spurt after winter rains. Rabbits and rats introduced over 70 years ago severely altered the islet's ecosystem by decimating native plants, allowing alien plants to dominate, and impacting smaller seabird species. The eradication of feral rabbits in 2005 has allowed recovery of some native plants but also the proliferation of several invasive weeds. An attempt to eradicate Pacific rats (Rattus exulans) in 2009 failed and rats are still present on the island. Lehua is owned by the U.S. Coast Guard and managed by the State of Hawaii as a seabird sanctuary. There is no evidence of permanent human habitation, but several stone structures built by ancient Hawaiians are present, and Hawaiians probably visited Lehua 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, which is maintained by the Coast Guard.

Key Biodiversity Lehua Islet is important for the number and diversity of breeding seabirds it supports and for the presence of several seabird species that are rare or have restricted breeding ranges. Recent surveys documented over 25,000 pairs of 11 seabird species nesting or attempting to nest on Lehua. Wedge-tailed shearwaters are the most numerous species on the island, with an estimated 23,000 pairs. The Brown Booby colony on Lehua is the largest in the Hawaiian Islands with 521 breeding pairs, and the Red-footed Booby colony is one of the two largest in the Hawaiian Islands, with 1294 pairs and approximately 4288 total individuals. The colonies of Laysan Albatross (28 pairs, 93 total individuals) and Black-footed Albatross (16 pairs, 53 total individuals) are small but appear to be growing and are important because these species have restricted breeding distributions and Lehua is one of the few high islands where they nest. Other species nesting on the islet include Christmas Shearwater, Bulwer's Petrel, Red-tailed Tropicbird, and Black Noddy. Newell's Shearwater, which is listed as threatened under the U.S. Endangered Species Act, and Band-rumped Storm-Petrel, a candidate for listing, attempt to nest on Lehua in small numbers, but predation by alien rats makes it difficult for these small seabirds to nest successfully. These species appear to be declining in Hawaii and may be difficult to manage on the larger Hawaiian Islands. Offshore islets such as Lehua may become increasingly important in the conservation of these species because their small size makes it more feasible to eradicate predators and manage other threats.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Black-footed Albatross Phoebastria nigripes breeding  2005  16 nests  good  A1  Near Threatened 
Laysan Albatross Phoebastria immutabilis breeding  2003  28 nests  good  A1  Near Threatened 
Wedge-tailed Shearwater Ardenna pacifica breeding  2002  23,000 nests  good  A4ii  Least Concern 
Newell's Shearwater Puffinus newelli breeding  2002-2004  present  poor  A1  Endangered 
Red-tailed Tropicbird Phaethon rubricauda breeding  2002  200 nests  good  A4ii  Least Concern 
Brown Booby Sula leucogaster breeding  2003  521 nests  good  A4ii  Least Concern 
A4iii Species group - seabirds breeding  2002-2005  25,500 nests  A4iii   

IBA Monitoring

2009 high not assessed low
unset
Medium - based upon reliable but incomplete / partially representative data

Human intrusions and disturbance recreational activities happening now small area/few individuals (<10%) no or imperceptible deterioration low
Human intrusions and disturbance work and other activities happening now small area/few individuals (<10%) no or imperceptible deterioration low

Whole area of site (>90%) covered by appropriate conservation designation  Unknown  Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity  low 

Habitats

IUCN habitat Habitat detail Extent (% of site)
Rocky areas Rocky flats & barrens  50%
Shrubland Arid lowland scrub  20%
Grassland   30%

Land ownership Lehua Islet is completely owned by the U.S. Coast Guard, but it is managed by the State of Hawaii as a seabird sanctuary.

Land use

Land-use Extent (% of site)
nature conservation and research 100%
Notes: All of Lehua Islet is managed as a seabird sanctuary by the State of Hawaii. Conservation efforts are underway to restore populations of native plants and animals and remove alien species. Several tour companies on Kauai offer day trips that visit offshore waters of Lehua for snorkeling, whale-watching, and sight-seeing. Landing is allowed on the shoreline, but access to the rest of the island is prohibited without a permit. The Coast Guard maintains a solar-powered, lighted navigational aid at the summit of the island, which is serviced occasionally by helicopter.

Access/Land-Owner requests Permission to land on the island must be obtained from both the Coast Guard and the State of Hawaii

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Lehua Islet. Downloaded from http://www.birdlife.org on 24/11/2014

To provide new information to update this factsheet or to correct any errors, please email BirdLife