In the winter, we get nice mixed flocks of finches. This year we have seen an unusually large
number of Cassin's Finches (CAFI), Haemorhous cassinii , but we almost always have plenty of
American Goldfinches (AMGO), Spinus tristis, Pine Siskins (PISI), Spinus pinus,
and Lesser Goldfinches (LEGO), Spinus psaltria. This image shows all four of these species together on a tray feeder.
There's 6 American Goldfinches, two Pine Siskins, a Cassin's Finch, and a male and female Lesser Goldfinch.

Note the largest is the Cassin's, then the Americans, while the Lessers and Pine Siskins are the smallest, about the same size.