The goal of the pictures in a field handbook is to present the essential type, the Platonic ideal of the species in question. His son Lee Allen Peterson says that his father's rendering of a robin:
"was not just any old robin, but the perfect robin. Somehow, he was able to convey a bird not at a specific moment in time, awkwardly posed with feathers in disarray, but rather, as the mind saw it, the robin idealized, with feathers neatly patterned and plump."
|American Robin by Roger Tory Peterson from|
Peterson Field Guide to Birds of North America
|American Robin, photo courtesy Wikipedia|
"His results were all the more remarkable when one watched how they were achieved. He worked mostly from memory, using only a dry, beat-up specimen of the bird for details of anatomy and occasionally a photograph or two. And he was able to piece together an image of the bird as it should have been. Not just any robin, but all robins."Book: Peterson Field Guide to Birds of North America