The McIlhenny Natural History Collection was begun by Edward Avery McIlhenny (1872-1949), scion of the prominent Louisiana family which since 1868 has produced the world-famous Tabasco hot pepper sauce. President of the family enterprise, McIlhenny was also a well-known conservationist who established a bird sanctuary and botanical garden on the family properties at Avery Island, Louisiana, now known as the Jungle Gardens. In 1971, McIlhenny’s nephew, the late John Stauffer McIlhenny, donated the natural history portion of his library to LSU, where it was combined with existing holdings. Since then, it has been further developed and is now one of the most prestigious of its kind, with particular strengths in New World botanical and ornithological illustration.

Among the more notable works in the collection are the double elephant folio edition of John James Audubon's Birds of America, Mark Catesby's The Natural History of Carolina, John Gould's Hummingbirds, Edward Lear's Illustrations of the Family of Psittacidae, or Parrots, and Sir Joseph Banks' Florilegium. A complete run of Curtis's Botanical Magazine, published continuously since 1787, is held, along with herbals dating back to the Renaissance and beyond. More than 220 illustrations of native Louisiana plants commissioned by Louisiana State University and created by distinguished Australian botanical artist Margaret Stones are also a part of the McIlhenny Collection.

Recent acquisitions include an archive of 32 original pencil drawings—thirteen in Audubon's own hand—associated with the production of the Royal Octavo edition of Birds of America. We also collect  botanical and ornithological illustrated books by Japanese artists who made important contributions to the genre.

Although many items have been added since its publication, Nature Classics: A Catalogue of the E.A. McIlhenny Natural History Collection (1987) is a good introduction to LSU’s holdings as well as to the history of scientific illustration in general. A second catalog, Aves: A Survey of the Literature of Neotropical Ornithology (2011), describes the library’s collection of books related to the birds of the American tropics. The printed catalog is also available as an online exhibition.