Bird Identification: What type of bird is this?, 2 by oschink

oschink wrote:
I believe this is a finch, but I do not know how to tell the difference between a purple finch and a house finch. According to the book I have, the house finch isn't supposed to be in Wisconsin, but this looks more like a house finch to me than a purple finch.

Does anyone know what this is? If so, what is the "defining feature" that allows you to know this?

Taken yesterday in Northeast Wisconsin.

Thank you!