When an item has "[YYYY printing]" in the volume information, this is meant to highlight that the items associated with this title are all different printings of the same edition. These books have the same content and pagination but the title page is different.
Another way to detect different printings of the same edition is to compare the copyright statements, for example:
In the case of Birdcraft, the 1899 printing has an original copyright date of 1895 and a later date of 1897: "Set up and electrotyped April 1895. Reprinted January 1896. Reprinted with additions, and new illustrations October 1897; June 1899.”
https://www.biodiversitylibrary.org/item/56637
1900 printing: same as 1899, except for addition of "December 1900"
https://www.biodiversitylibrary.org/item/115300
1903 printing adds: "April, 1903"
https://www.biodiversitylibrary.org/item/33139