Donald Ogden Stewart was a fine writer (movie fans need only to remember his screenplay for "The Philadelphia Story" to be convinced of that), and he was understandably chosen to try to duplicate the success of Robert Benchley's short comedic movies. But Stewart's style of presentation doesn't usually work as well as Benchley's does. As a result, this short comedy is only fair, although it does have some good material.
Stewart appears as a lecturer presenting a talk on birds to a Women's Club (exactly the kind of format that Benchley used so effectively). The material seems well-written, but a different style - or perhaps a different, flatter voice - might have made it work better. It probably would also have worked rather well in print.
In any case, Stewart's vocal inflections and delivery style call too much attention to the offbeat nature of the material, and thus stop it from having the maximum effect. Benchley's readings, on the other hand, make odd material even funnier by making it seem reasonable to accept it at face value.