Alau is a fairly large islet, approximately 5 acres in size and 148 ft. in height. It is located a short distance offshore south of Hāna. The islet is a cinder cone and has a central sloped section, with sheer cliffs on the south and west side, a few ridges on the east side which protrude from the central cindery section toward the sea, and a small cinder and boulder beach between the two ridges. Vegetation on Alau is made up primarily of coastal plants dominated by naupaka (Scaevola taccada) and ‘ākulikuli (Sesuvium portulacastrum) with patches of nanea (Vigna marina), alena (Boerhavia repens), ‘īhi (Portulaca lutea), and schiedea (Schiedea globosa). There is a grove of about a dozen niu (coconuts or Cocos nucifera) on it’s summit. The west tip has some lantana (Lantana camara) with nanea and love-in-a-mist (Passiflora foetida) sprawling over the area. Just below, on the sheer west cliffs, a few rare native plants exist, including numerous schiedea and several maia pilo (Capparis sandwichiana). The slopes are predominantly naupaka and grasses including Henry's crabgrass (Digitaria ciliaris) and wiregrass (Eleusine indica), with scattered pōpolo (Solanum americanum), pigweed (Portulaca oleracea), sow thistle (Sonchus oleraceus) and pualele (Emilia fosbergii).
The near ocean areas are blanketed with ākulikuli, alena, and ‘īhi. The rare ‘īhi (Portulaca villosa) has been found on the windswept cinder ledges on the east side along with the native sedge (Cyperus phleoides). Most of the islet is heavily burrowed by ‘ua‘u kani (wedge-tailed shearwaters or Puffinus pacificus), especially near the top of the islet. Koa‘e kea white tailed tropic birds (Phaeton lepturus dorotheae) and ‘iwa (frigatebirds or Fregata minor palmerstoni) may nest there. Many noio (black noddies or Anous minutus melanogenys) and‘akekeke (ruddy turnstones or Arenaria interpres) can be seen.
As with all state Seabird Islet Sanctuaries, visiting Alau is prohibited. They are rare places where seabirds can nest with few or no predators and no large mammals (including humans) trampling and crushing the burrow where they raise their young. Turtles and seals can rest on their tiny shores without harassment and they are havens for native insects and plants without people constantly inadvertently bringing in weed seeds and other alien pests. Respect and admire these places through binoculars, peacefully, from shore.
