We have had dozens of Pine Siskins coming to our feeders all winter. As much as we enjoying seeing them; we always look forward to the arrival of Goldfinches. Yesterday, Nancy saw the first Goldfinch on our spiral feeder. Later that day, I saw another. They were both males and were well on their way to having their full breeding colors. The males will be a brighter yellow and have a black forehead. The females are a duller yellow-olive and do not have the black forehead.
Nyjer/Thistle is often the seed that comes to mind when people think about feeding Goldfinches. Nyjer works well but does have some issues. It takes on moisture quickly and can leave a mess under the feeder. Goldfinches are also attracted to sunflower chips. The great thing about feeding sunflower chips is that they will attract a wide variety of birds, they are less messy, last a little longer in wet weather and cost about the same as Nyjer. You can mix the smaller chips (Fine) with Nyjer and feed in a typical Finch Feeder. Or, you can use a courser chip (Medium) in most any tube or hopper feeder. As I've mentioned before, we have a very busy Super Spiral Seed Feeder (Bird Quest) that hangs off of our deck. We fill it with a mix of Medium SF Chips and Nyjer. We'll pour in layers of each so that it looks like a parfait. That way we attract the finches along with any other sunflower loving bird.