Dodoes existed in 1598 and became extinct in the 1600s. Because of their amusing appearance, particularly in the book "Alice in Wonderland," they have become a metaphor for extinction--particular for things that are recently extinct.
There is a saying, "dead as the dodo," for anything fashion or custom or technology that is recently extinct or on the way to extinction. "Black-and-white film is dead as the dodo." Or I might say "Oh, I love black-and-white photography but maybe I am just an old dodo," meaning I am part of a nearly "extinct" generation.
Dodoes lived for long enough for naturalists to collect them, stuff them, and put them into museums. In your passage, the metaphor is of someone studying a stuffed dodo in a museum and not realizing that the real dodo is extinct.