The male American Goldfinch.
The female Goldfinch is rather drab in her yellow/green coloring. In the winter both sexes will look like this. The male molts into his breeding plumage in the spring and molts again in the fall back to the olive/green coloring.
Unlike many birds Goldfinches wait to nest later in the summer when they know their food source is good and plentiful enough to feed young nestlings. They like to wait until the thistle plants mature. Thistle down from the flowers is used to line their nests and the seeds are a preferred food. While most birds feed their young a diet of high-protein insects, Goldfinches prefer seeds at all times of the year. They feed their young a slurry of seeds and parental saliva.
The Pine Siskin, which is mostly only a winter visitor, has been around Crane Lake all summer. This little brown bird (LBB) is distinguished by the little bit of yellow that they sport on their wings. The Pine Siskin may look like a Sparrow, but they are not, they are in the finch family. They are seed eaters and they can clean out your thistle feeders in a hurry. Last night there was a flock of 50 birds visiting my feeders. Listen for their little trill calls when you are in the Crane Lake area.