In the summer, Nelson’s sharp-tailed sparrow feeds mainly on insects and spiders, with some small crustaceans, snails and worms also eaten. At other times of the year, its diet consists almost entirely of vegetation and seeds. Usually, Nelson’s sharp-tail sparrow forages near the ground, probing in mud and picking up food items from the ground, foliage and water (3) (5) (7).
The breeding behaviour of Nelson’s sharp-tail sparrow has not yet been fully described, but it is thought that the male attracts a partner by singing in flight and from a perch. The male likely breeds with more than one female. The female constructs the nest alone, possibly with material collected by the male. In early June, 3 to 5 eggs are laid, which are then incubated by the female for around 11 days. The young fledge at around ten days, but are cared for by the female for two or three more weeks. The female may raise two broods in a single summer (3) (7).