Pine Siskins and Common Redpolls, down from Canada. Some years the winter population is bigger than others. Irruption of finches are driven by shortages in the crop of conifer seeds (such as spruces and pines) and catkins (such as birch and alder) in the North. In search of food, flocks of siskins and redpolls travel south to find a steady supply of food at backyard bird feeders.
Another winter bird that hangs out under the finch feeder is the Dark-eyed Junco. During winter, Dark-eyed Juncos form fairly large flocks, and you may see them forage with other sparrows and bluebirds. And I see the inquisitive Black-capped Chickadees and woodpeckers also sample the seeds out of the finch feeders.
Different Goldfinches in America http://goo.gl/aI9msF
A Closer look at Dandelions http://goo.gl/YfhxHY
Round fluffy white seeds floating in wind http://goo.gl/xmKiCN
Sunflowers Up-close: The Strange Journey of an American Plant http://goo.gl/eitZa1
Nyjer (thistle) isn't related to Canada Thistle http://goo.gl/ZZBcgM