The Laysan rail, scientifically known as Zapornia palmeri, was a diminutive, flightless bird that once graced the Northwestern Hawaiian Island of Laysan. With a length of a mere 15 centimeters from beak to tail tip, this rail had evolved with significantly reduced wings and tail, measuring just 5.4 centimeters and 2.5 centimeters respectively. It possessed a mere eight primary feathers, fewer than its volant relatives. The bird's bill was strong and straight, spanning 1.8 centimeters, and it boasted well-developed legs. Its overall proportions bore resemblance to the small rails of the genus Laterallus, such as the black rail.
The Laysan rail's plumage was a paler echo of the Baillon's crake, to which it was closely related. Its face, throat, breast, and supercilium were a dull medium gray, while the back, wings, and crown were pale brown with pronounced feather shafts, save for the wings. The scapular and flank feathers were tinged with sandy brown. Unlike many in the genera Porzana and Rallus, the characteristic black-and-white barring of the lower belly and undertail coverts was notably subdued. The bird's feet and bill were a yellowish-olive green, and it had a striking ruby red iris. Both sexes appeared similar, with downy young presenting a stark black coloration, long dark legs, and a yellow bill. Immature birds displayed a pale brown underside.
The Laysan rail was exclusively found on Laysan Island, with an introduced population briefly existing on Midway Atoll. The bird's habitat was closely tied to the island's unique ecosystem.
Endemic to Laysan, the rail was also introduced to Midway Atoll. There were unconfirmed reports of similar flightless rails on other Hawaiian islands, but these were likely distinct species that had gone extinct prior to Western contact.
This rail was an opportunistic feeder, primarily consuming invertebrates and occasionally plant matter, seeds, and seabird eggs and carcasses. It was known for its aggressive nature, particularly towards the Laysan finch, often stealing eggs cracked open by the finches. The Laysan rail was a nimble creature, using its wings for balance when running or jumping. It was most active during cooler parts of the day and was known to be fearless, often approaching humans if they remained still.
The Laysan rail was a vocal bird, emitting soft warbling chirps when active. During courtship or territorial disputes, it produced rattling, scolding calls reminiscent of a mechanical alarm clock. At dusk, the entire population would engage in a brief vocalization session, described as sounding like marbles cascading on a glass roof.
The breeding season commenced in April with courtship and nest-building, with egg-laying occurring from May to June. Nests were constructed in tussocks of native and introduced grasses. Clutches typically contained three eggs, which were incubated by both sexes, though females appeared to take on the majority of this duty.
There were no similar species in its immediate vicinity, as the Laysan rail was unique to its environment.
The Laysan rail's diet consisted mainly of invertebrates, such as moths, brine flies, blowflies, and their larvae. It also consumed plant leaves, seeds, and occasionally the eggs and carcasses of seabirds.
The Laysan rail is classified as Extinct. The introduction of domestic rabbits to Laysan Island led to habitat destruction, and the subsequent introduction of rats during World War II further sealed the fate of this species. The last sighting of the Laysan rail was on Eastern Island in Midway in June 1944.