The male blue grosbeak has brown wings, but your bird could be one in the process of moulting, or replacing old feathers with new ones, giving it an unusual appearance. If the bird is smaller, could be an indigo bunting, going through the same moulting process.
More than likely the bird you saw was the male of the brown-headed cowbird.
A mallard is a bird that has an iridescent green head and brown on the body. The ring necked pheasant is another bird with a brown body, and an iridescent green head.
Blue bird
Bald Eagle.
brown headed cow bird
vulture
vultures.
The Bald Eagle
Bald Eagle.
vulture
vulture
a bald eagle
It could be a bird in the pheasant family. Ring-neck pheasants have primarily brown bodies with some mottling of colors with a blue to blue/green head. One variation of the ring-neck is called an Afghan which looks like the ring-neck but has no white ring on the neck.