NOTE: The Two Birds Series of etchings (Mordock, Lethbridge et al) encompasses a set of twelve (12) etchings. Each etching, with one exception, features two adult birds sitting on a branch with various other birds, butterflies, dragonflies and even a frog featured. For the purposes of my research the firm that did this etching has been designated as U2 i.e. Unknown 2. They were very prolific and there are about 27 etchings that can be assigned to them.
Ref. Etched Pattern Glass, Acid Etched Goblets and Tableware of the 1880s, p 138-141