The cross-billed deformity in birds was recognized by two reports issued in 1879.
Dr. T.M. Brewer noted the condition in a magpie, which was apparently the Black-billed Magpie. This report was published in the Familiar Science and Fancier's Journal (June 1879, p. 106), which was not found online, though other volumes are available.
A Horned Lark shot December 9, 1879 near Grinnell, Iowa, also with this condition, was well documented. Professor H.W. Parker, with the Agricultural College of Iowa, sent drawing and descriptions to J.A. Allen, for the article issued in the Bulletin of the Nuttall Ornithological Club.
"Both mandibles are of the same length, rather longer and slenderer than usual, the upper curving downward and the lower upward, passing by each other and crossing in the same manner as in the crossbills."
Allen also noted: "Deformities of the bills in birds is not a very rare occurrence, but examples are rare in which the mandibles are so fully and symmetrically crossed as in the present case." At the end of the article, author Allen, of Cambridge, Mass., noted "a few other cases are on records" but did not provide any notes regarding the instances to which he was referring.