Nazca Booby (Sula granti) and Brewster's Brown Booby (S. leucogaster brewsteri) are tropical sulids that normally occur only in the eastern Pacific Ocean. In this paper, we report on recent observations of Nazca Booby and Brewster's Brown Booby in the Hawaiian Islands, including the first apparent nesting records, and we summarize other occurrences of these taxa in the Hawaiian Islands and Johnston and Palmyra Atolls. Genetic research has shown significant population structure between Brown Boobies in the eastern and central Pacific, but little population structure in Masked Boobies (S. dactylatra), indicating that the Eastern Pacific Basin has served as a dispersal barrier in Brown Boobies but not in Masked Boobies. Recent observations of brown-headed male Brown Boobies from the central Pacific nesting on Isla San Benedicto near Mexico indicate that some eastward dispersal is now occurring. The observations of Nazca and Brewster's Brown Boobies nesting in the Hawaiian Islands and on Johnston Atoll indicate that dispersal across the Eastern Pacific Basin is occurring in both directions.

ABSTRACT We conducted surveys from 2002 to 2005 and compiled historical information on the avifauna of Lehua Islet, Hawai‘i, to assess its conservation status and management needs. Thirty-five bird species have been observed on Lehua since 1931, including 18 seabirds endemic or indigenous to the Hawaiian Islands, one resident indigenous waterbird, six migratory waterbirds, and 10 alien land birds. We observed 29 of these species during surveys from 2002 to 2005, 13 of which had not been recorded on the islet previously. Over 25,000 pairs of eight seabird species were documented to breed on Lehua, including previously unknown breeding colonies of Black-footed Albatross (Phoebastria nigripes) and Laysan Albatross (P. immutabilis), and the largest breeding colonies of Brown Booby (Sula leucogaster) and Red-footed Booby (S. sula) in the Hawaiian Islands. Remains of a Newell's Shearwater (Puffinus auricularis newelli) chick and a Band-rumped Storm-Petrel (Oceanodroma castro) chick were found, demonstrating that those species have nested on the islet and probably still do. The nesting season varied among species, with most species breeding from March to August, and at least one species breeding in every month. Predation by alien Polynesian rats (Rattus exulans) and Barn Owls (Tyto alba) is the most serious threat to nesting seabirds on Lehua. Sediment beneath a Barn Owl roost contained hundreds of bones from a variety of bird species, including Brown Noddy (Anous stolidus), which has been extirpated from the islet. Feral rabbits (Oryctolagus cuniculus) are suppressing vegetation that could provide additional nest sites for Red-footed Boobies and help prevent erosion and burying of sea-bird burrows. The most urgent management needs on Lehua are eradication of alien Polynesian rats, alien Barn Owls, and feral rabbits. Rocky offshore islets like Lehua may become increasingly important in seabird conservation because their small size makes it more feasible to manage threats, and because they are less likely to be affected by increases in sea level associated with climate change.

Abstract.The U.S. Fish and Wildlife Service funded field surveys between 2001—2004 in order to research and evaluate the biological diversity of Lehua, a small off-shore islet to the north of Ni‘ihau and west of Kaua‘i, Hawai‘i. These surveys focused on the conservation status of Lehua’s biota with a special focus on botany, ornithology, entomology, and alien species management. In this report, we present the results of that research and make management,recommendations,for,the,long-term,protection,and enhancement,of,Lehua’s indigenous,and,endemic,biotic diversity. Significant discoveries include previously undocumented,breeding colonies of Black-footed Albatross (Phoebastria nigripes) and Laysan Albatross (P. immutabilis); the largest breeding,colony,of Brown,Boobies,(Sula leucogaster) in the Hawaiian Islands (521 pairs); the presence of Newell’s Shearwater (Puffinus auricularis newelli), a threatened species, and Band- rumped Storm-petrel (Oceanodroma castro), a candidate for listing; the

2 Abstract. The U.S. Fish and Wildlife Service funded field surveys between 2001—2004 in order to research and evaluate the biological diversity of Lehua, a small off-shore islet to the north of Ni'ihau and west of Kaua'i, Hawai'i. These surveys focused on the conservation status of Lehua's biota with a special focus on botany, ornithology, entomology, and alien species management. In this report, we present the results of that research and make management recommendations for the long-term protection and enhancement of Lehua's indigenous and endemic biotic diversity. Significant discoveries include previously undocumented breeding colonies of Black-footed Albatross (Phoebastria nigripes) and Laysan Albatross (P. immutabilis); the largest breeding colony of Brown Boobies (Sula leucogaster) in the Hawaiian Islands (521 pairs); the presence of Newell's Shearwater (Puffinus auricularis newelli), a threatened species, and Band- rumped Storm-petrel (Oceanodroma castro), a candidate for listing; the presence of endemic and indigenous insects as well as alien ants; the presence of 22 species of native plants persisting despite the effects of rabbits; confirmation of the continued presence of alien rabbits (Oryctolagus cuniculus); documentation on the presence of Polynesian rats (Rattus exulans); general observations on geology and ecology, in addition to biotic checklists which includes discussions and historical accounts of all 31 bird and 55 plant species that have been observed on the island; a comparative checklist of vascular plants for all three of Kaua'i's offshore islets including Lehua, Ka'ula, and Moku'ae'ae; a preliminary checklist of macro-algae; a preliminary checklist of arthropods; and a discussion on future biological restorations. The most urgent management needs on Lehua are eradication of alien rats and rabbits, control of alien Barn Owls and Cattle Egrets, and establishment of a trail system and standard survey protocols to minimize the extent of human disturbance to nesting birds.