An 1896 letter from the Mint correspondence in the National Archives, recently transcribed by Newman Portal, asks about Peter, the Mint eagle. The letter writer asks for more specifics regarding the oral tradition of this national bird, who was said to have inhabited the Mint, broke a wing on the machinery, died, and was thereafter stuffed for posterity. The missive is addressed to the Philadelphia Mint Superintendent and the response is recorded as follows.

Left unexplained is how the bird navigated to the new Mint building that was put into operation c. 1833. The earliest mention of Peter appears to be in Elizabeth Johnston's A Visit to the Cabinet of the United States Mint (1876), where "an old citizen of Philadelphia" is cited as the authority for the story. Peter is today comfortably ensconced in the visitor's area at the U.S. Mint in Philadelphia

Link to "Peter the Mint Bird" letter:
https://archive.org/details/peterthemintbirdstory18960507/page/n3/mode/2up

Link to U.S. Mint general correspondence on Newman Portal:
https://nnp.wustl.edu/library/archivedetail/515202

Link to Elizabeth Johnston's A Visit to the Cabinet of the United States Mint on Newman Portal:
https://nnp.wustl.edu/library/booksbyauthor/1079