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Poecile carolinensis
A rather small bird with distinctive markings on his head.
Found at backyard feeder in urban residential setting.
Not enough white on the tertials for a Black-capped. Plus, you're just a bit south of their regular range in Indiana.
You may also want to look up the Carolina chickadee...compare them both to the birds you are seeing. The Carolina is said to have less white streaking in the wings and the rust color on the sides is lighter. Your state is one like mine where the two types overlap. Honestly I can't see much of a difference between the two.
its like what James Funk said A Black-Capped Chickadee
they are one of the most common wintering song birds of the northern US