Nihoa Island itself had temperatures of eighty and fifty-four degrees farenhight from 1969 to 1974. These birds usually build their nests in holes or crevices in or under rocks. The average nest is small about fist size of a six-inch diameter. Incubation periods in the wild are unknown, but in captive finches incubation is fifteen to sixteen days. Parental care has not been studied in with populations.
Captive females incubate the eggs and the male feeds the female during the incubation period.
Both sexes feed the nestlings and fledglings. The Nihoa is a classic example of an omnivore. Their diet consists of plant seeds leaves, flowers, buds, fruit and eggs. These finches have been observed feeding on green flower heads and fruit of Chenopodium, partly green seeds of Portulacabillosa, and seeds and leaf buds of Sidafallax. However like the Laysan finch, this finch probably cannot crack the larger eggs, although it would probably eat any open egg.