Nest located over or near fresh water, especially in emergent wetland. Drinking water probably required, at least when seeds and grains are major foods. Frequents fresh emergent wetlands. Yearlong, diurnal activity. Not migratory over most of range, but leaves northeastern California in fall and winter, presumably migrating south.
Flocks become nomadic in fall seeking food.
In winter, flocks become more widespread from Marin to Santa Cruz cos. Usual breeding season mid-April into late July. Colonies were even larger in former decades. Young leave nest at about 13 days. Highly gregarious in all seasons.