Editor’s Note: After publishing his first field guide, Roger Tory Peterson signed on as 蜜柚APP’s education director and the magazine’s art director—and went on to illustrate 42 of its covers. In this feature from 蜜柚APP’s November-December 1942 issue, renowned naturalist, author, and photographer Edwin Way Teale combines a portrait of the artist with documentation—in words and photos—of his process for researching and illustrating the geese featured on that issue’s cover. Roger Tory Peterson—to borrow an expression from the sporting page—is a triple-threat ornithologist. He is an artist, a lecturer, a writer. By his paintings and photographs, by his illustrated lectures, by his pamphlets, articles and books, he broadcasts his enthusiasm for birds. That enthusiasm has been burning steadily for nearly a quarter of a century. During recent days, while I have been following him about like some photographic Boswell to record on film the successive steps in...