The Delmarva Ornithological Society started at a meeting of 80 charter members on 18 February 1963 at the Wilmington Institute Free Library.  At this meeting by-laws were adopted and officers selected and sworn in. The mission statement adopted at the convention was “The object and purpose of this Society shall be the promotion of the study of birds and the advancement and diffusion of ornithological knowledge”.  Perhaps the most obvious change in the DOS during its first fifty years has been the greater emphasis on conservation. The promotion of conservation had always been a feature of the DOS and in the mid-1990s the following clause was added to the Society’s mission statement – “and the conservation of birds and their environment”.

In 2013 DOS celebrated 50 years of birding, bird conservation, and community.  From a charter membership of 80 the society has grown to over 500 members.  To learn more about the history of DOS please take a look at the article “The First 50 Years of the Delmarva Ornithological Society,” published in the Delmarva Ornithologist in 2013.