Identificaciones de jonelofson

Very tiny bird, extremely difficult to find and to photograph.

I'm really struggling to tell the difference between an American Tree Sparrow and a Chipping Sparrow. Any hints would be much appreciated

This very young fledgling appears off to a tough start in life. Its feathers are in quite a rough state. It was doing a good job getting food, that's a good sign.

Tons of these birds around!