The Aldabra rail is an unfussy eater, with a varied diet and a tendency to investigate any strange object as potential food (3). It searches among leaf litter, from where it plucks small beetles and other invertebrates, and will follow the tortoises of Aldabra to feed in the litter disturbed by their passing. Flies and mosquitoes are pecked from the shells of tortoises, and the carcass of a dead tortoise is a good source of small beetles and flies for the rail. The Aldabra rail does not eat the flesh of a dead tortoise, but it will consume the flesh of dead crabs. Small molluscs found just above the tide line are cracked open with the bill and consumed, and the rail forages among the roots of mangroves for snails and small crabs (3). When feeding in water, the Aldabra rail submerges its head and vigorously rakes the mud with its bill. These birds are able to drink both fresh and saltwater (2).
Aldabra rails are monogamous birds that form permanent pair-bonds and together defend a territory. Females without a male partner also hold territories. A clutch of three or four eggs are usually laid in December, into a flimsy nest constructed of twigs and leaves, situated in a depression among rocks (2), or into a more substantial nest shaped like a deep cup and well-concealed in foliage (3). The chicks are fed by the parents until they become independent at 12 to 15 weeks of age, after which the parents become aggressive toward their offspring (2). Often only one young in each clutch of eggs survives, possibly due to predation. Surviving chicks begin breeding at nine months, and Aldabra rails live for up to six years (2).
Land crabs (Cardisoma carnifex) and introduced rats (Rattus rattus) are thought to take eggs and possible kill some chicks, but there are no natural predators of adult Aldabra rails on Aldabra Atoll (3), the most likely reason why the rail has evolved to be flightless (6). The lack of predators means that the Aldabra rail shows no fear of humans, or the cats that occur on some of the Aldabra islands (5).