The male, slightly larger than the female, has more iridescence on the head and throat. Grackles are common nesters throughout North America east of the Rockies, nesting in shelterbelts, farmyards, marshes, and towns. The male grackle usually mates with one female. Flocks feed in fields, lawns, woodlots, and bottomlands. Grackles have a diet somewhat similar to that of redwings, but grackles are more predatory, feeding occasionally on small fish, field mice, songbird nestlings, and eggs.
Grackles also feed on acorns and other tree fruits in winter.
Grackles often roost in cattail marshes with other blackbirds in late summer, but grackles prefer roosting sites in upland deciduous or pine trees in their wintering locations in the Southern United States. A robin-sized bird, the male yellowhead has a black body with a conspicuous yellow head and breast and a white wing patch seen only when the bird is in flight. The female is smaller and browner with yellow throat and breast and does not have a white wing patch. Yellowheads are locally abundant nesters in deep-water marshes of the northern Great Plains and western North America. Like redwings, male yellowheads often mate with more than one female.