Are you referring to the owl's head at the upper left of the upper right "1" on the front of the bill? It's easier to see with a magnifying glass...
Q. Where is the second bird on the one dollar bill?
A. On the face of the bill, upper right side, (same side as the green Treasury Seal) in the upper left corner of the frame around the numeral "1."
Look in the exterior portion (upper left) of the indentation of the frame around the numeral "1" in the upper right corner of the bill. You will need a very strong magnifying glass, loupe or pocket microscope. There is a small owl sitting there.