Philadelphia architect and amateur ornithologist, Baily was the prime mover in founding the Delaware Valley Ornithological Club in 1890, and one of the three surviving members to disband the Pennsylvania Audubon Society in 1936. For long years acted as inspector of birds and mammals for the Port of Philadelphia, in which capacity he helped to curtail the sale of bird feathers to fashion experts of the day.

His correspondence with Witmer Stone, which makes up the main part of this collection, was concerned with field trips, bird collecting and recording lists for the Philadelphia area. Some letters were in connection with their mutual interests in the Delaware Valley Ornithological Club and in the Pennsylvania Audubon Society. Included is an acknowledgement of his election to the Academy, a manuscript copy of an article entitled “Vireos of the Eastern U.S.,” field notes and [UNK] slides.