I just finished reading "The Rise & Fall of the Dinosaurs" by Steve Brusatte. He goes over their entire history of their evolution up to the extinction event caused by the asteroid hitting the earth in the Yucatan. The only dinosaur survivors were birds and he goes on to explain why birds are in fact dinosaurs. Later I looked out the back window where I leave trays of food for the juncos (snowbirds) and there they were. Glad I wasn't looking at a 40 foot T Rex.
The only feeder I have out there now is a ground feeder since juncos will only feed on the ground and not a hanging feeder. I see a sparrow or two at times and they could be song sparrows...not sure. A squirrel comes by once in a while just for the sunflower seed only and leaves the rest alone. For some odd reason he buries them instead of eating them right away. Shopping for a hanging feeder now. Winter has barely started so I expect more customers.
Where are you located? That determines what varieties of birds you will have. I have noticed that about juncos; that they only feed on the ground. Doves are the same way. They will occasionally feed from the feeder but not often.