Laysan (Hawaiian: Kauō), located northwest of Honolulu at N25° 42' 14" W171° 44' 04", is one of the Northwestern Hawaiian Islands. It comprises one land mass of 1,016 acres (4.114 km²), about 1 by 1.5 miles in size (1.6 by 2.4 km). It is an atoll of sorts, although the land completely surrounds a shallow central lake some eight feet (2.4 m) above sea level that has a salinity approximately three times greater than the ocean. Laysan's Hawaiian name of Kauō means egg, referring to its shape and how much life springs from the island.
Laysan is the second largest single landmass in the Northwestern Hawaiian Islands, after Sand Island at Midway Atoll. Laysan was created by coral growth and geologic upshift. The fringing reefs surrounding the island cover about 735 acres. Lake Laysan, the 100 acre, brown, hypersaline lake in the island's interior, has varied in depth over the decades. In the 1860s, the lake was at most 30 feet deep, but by the 1920s it averaged three to five feet deep, because of the buildup of sand that had been blown away in sandstorms. The best way to find fresh water on Laysan is to observe where the finches are drinking; the fresh water floats on the saltier water and accumulates around the shore. The tallest point on the island is at fifty feet above sea level, on a large dune that covers much of the northern portion of the island.
In 1890, the Kingdom of Hawaii granted George D. Freeth and Charles N. Spencer permission to mine the guano on Laysan anyway, as long as they paid a royalty. This newfound attention to Laysan attracted scientists, and in the next decade, many of Laysan's unique species were scientifically examined for the first time. The working conditions at the guano mines were grueling, but there seemed to be more guano than Capt. Brooks had thought. Around 100 tons were extracted per day. In August of 1900, a fight broke out between the Japanese workers and the management when the workers refused to work anymore; this ended in two deaths and two injuries because of the language barrier.
Guano digging affected the island’s ecosystem dramatically. Professor William Alanson Byron of the Bishop Museum estimated that there were 10 million seabirds on Laysan in 1903, but eight years later the estimation was at little more than a million. In those eight years, the Pritchardia palms that were unique to Laysan, and the island’s sandalwood trees both became extinct.
1894 marked the arrival of Laysan’s most notorious inhabitant, German immigrant Max Schlemmer. Schlemmer introduced Belgium and European Hares as well as Guinea pigs on the island so as to prepare for a future meat canning business. This innocent move would prove to be crucial in the decline of Laysan.
In 1923, the Tanager Expedition arrived, and the rabbits were exterminated at long last. The bird population had been reduced to about a tenth of its former size, and three endemic taxa had become extinct, plus numerous other plant species. Two other endemic species, the Laysan Duck and the Laysan Finch, survive to this day, but are endangered.
All sorts of garbage that is thrown off of ships ends up floating to shore on Laysan. This poses a great danger to the birds, because they swallow the plastic, which remains undigested and crowds the stomach, leaving no room for actual food. Curiously, most of the plastic found is Japanese in origin. Additionally, in the 1990s, biologists found that a container of poisonous carbofuran had floated to shore and burst open above the high tide line, creating a "dead zone" which killed anything alive that went near it. This area is still off-limits.
Recently, an archaeologist examining sediment cores found pollen from coconut trees deep below the bottom of the central lagoon. This unexpected find raises several issues. Heretofore, no evidence existed that the coconut ever reached any of the Hawaiian Islands before the arrival of the Polynesian voyagers. Further, there has never been any physical evidence that the ancient Hawaiians extended their explorations of the Hawaiian chain beyond Nihoa and Mokumanamana (Necker). Dating the sediment containing the Cocos pollen is imprecise, but appears to be somewhere between 5,500 years ago, and the arrival of Europeans in Hawaiian waters in the late 1700s. The full length of the core was 70 feet and is thought to represent a record spanning 7,000 years. Coconut pollen was not found in the deeper (older) part of the core. However, cores from Guam in the western Pacific show the presence of coconut trees there as early as 9,000 years ago, well before human habitation. Hawaiian traditions suggest that the Hawaiians were aware that islands existed to the northwest, and the pollen evidence could be interpreted as proof of early Hawaiian visitation to Laysan. Clearly, more precise dating of the sediment layers will be crucial to better interpreting this find.
Laysan is generally regarded as the "gem" of the NWHI, with the most biodiversity. It is home to the Laysan Duck, the rarest duck in the world. The other native land bird of Laysan is the Laysan Finch, an opportunistic hunter. Eighteen other bird species nest here and use Lake Laysan, the only lake in the NWHI, as a rest stop or breeding ground. Laysan also has its share of native plants, many of which, such as Eragrostis variabilis, were extirpated from Laysan during its extinction period and then reintroduced by scientists afterwards, from other Leeward islands. Like most other of the NWHI, Laysan is home to Hawaiian Monk Seals and Green Sea Turtles.
- Laysan Finch, Telespiza cantans - endemic
- Laysan Duck, Anas laysanensis - endemic
- Laysan Albatross, Phoebastria immutabilis
- Black-footed Albatross, Phoebastria nigripes
- Short-tailed Albatross, Diomedia albatrus
- Great Frigatebird, Fregata minor
- Lesser Frigatebird, Fregata ariel
- White Tern (or "Fairy Tern"), Gygia alba
- Sooty Tern, Onychoprion fuscatus
- Gray-backed Tern, Sterna lunata
- Bristle-thighed Curlew, Numenius tahitiensis
- Pacific Golden Plover, Pluvialis fulva
- Christmas Shearwater, Puffinus nativitatis
- Red-tailed Tropicbird, ''Phaethon rubricauda rothschildi
- Brown Noddy, Anous stolidus
- Black Noddy, Anous minitus melangogenys
- Masked Booby, Sula dactylatra
- Brown Booby, Sula leucogaster
- Red-footed Booby, Sula sula rubripes
- Bonin Petrel, Pterodroma hypoleuca
- Laysan Rail (or "Laysan Crake"): Porzana palmeri -extinct
- Laysan ʻApapane - extinct
- Laysan Millerbird - extinct