After ***** ***** Audubon (American, 1785-1851), "Brown Pelican", No. 85, Plate CCCCXXI,
from Birds of America, hand-colored engraving, Havell edition,
the elephant folio paper should be watermarked J. Whatman/ 1838, sheet size should be 25 1/2 in. x 38 in.
This would have a value of $35,000 to $40,000, one having sold for $38,000 in 2011.
If this is a printed reproduction, which there are many, it would have a value of $250.00.
I have given you both possibilities for this piece. It is hard for me to tell from one photo under glass, so it might be worth it to take it to someone that can do a physical examination of the piece.
Do click the stars after you have read this answer.