Keeping apart in pairs or family groups, the Crimson Finch rarely forms flocks. The birds fight constantly, driving one another away from perches and fencing with their bills. Even pairs do not perch touching together or preen each other. Squabbling birds erect their face feathers and fan their tails; in a fight they raise one wing vertically. This aggressiveness does not extend to territory and several pairs may nest close to one another.
Crimson Finches range across northern Australia in pockets of tall wet grassland mixed with pandans and trees along streams. There they have also occupied patches around settlements with their own wells and troughs. The Crimson Finch is found across north, from Kimberleys to Mackay, QLD.
Crimson Finches eat seeds of a wide variety of grasses and herbs and, during the breeding season, many insects. They rarely feed on the ground, foraging mainly high of grass stems and gathering seeds by climbing nimbly among the stalks. Although living near open water they rarely drink from it, scooping drops of dew and rain from tips of grass blades instead.
The Crimson Finch mainly builds in pandanas palms but is also known to nest in cracks and crevices in buildings. Only the male brings material but both construct the bulky dome with an entrance tunnel of coarse grass, bark and leaves lined with feathers. Both sexes incubate 5-8 eggs for 12-14 days. Breeding occurs in September – May in Queensland and January - April in Western Australia and Northern Territory.