In the winter, it mostly wanders nomadically or makes regular migrations. Like other sparrows, it feeds principally on the seeds of grains and other grasses, also eating leaves, fruits, and other plant materials. Young birds are fed mostly on insects, and adults also feed on insects and other animals during and before the breeding season. In preying on insects, the Spanish Sparrow is opportunistic, feeding on whichever insects are most common.
Colonies may hold from ten pairs to hundreds of thousands of pairs.
Males spend more time constructing nests than females.