Last week my brother brought home a goldfinch and turned it loose at his house. I don't know why he brought it home, but it was in the cage because it had been hurt. The person taking care of it might have had cats around. Just a guess.
It was jumping around wanting out. When he opened up the box, it flew off. It never got to high but at least it was flying. He has feeders out, so it should have plenty to eat. Hopefully it will be okay and be ready for its flight north soon.