But for an errant pair of pochards, Europe might have made a fine physician out of Ernst Mayr. As it was, his sighting of the red-crested diving ducks in central Germany in 1923—the first in over seventy years—led to a career in ornithology and evolution that has seen him hailed as one of the world’s greatest biologists. Now in his ninety-eighth year, Mayr has published two major works that are the culmination of his lifelong scientific career. The Birds of Northern Melanesia (written with Jared Diamond) provides a detailed picture of one of Mayr’s principal fields of research—how birds develop into different species (“speciate”) on island archipelagos. The second, What Evolution Is, concerns the other grand theme of his researches—the elucidation of evolutionary theory—here presented in a form accessible to the general reader.
Ernst Mayr was born in 1904 in Kempten, Germany. From the earliest age he was a keen bird watcher, but for four generations the Mayrs had practiced as physicians, and family tradition was strong. Ernst was already enrolled in medical school when those distracting pochards appeared. He reported the sighting to the great Erwin Stresemann, then curator of birds at the Museum für Naturkunde in Berlin, who was so impressed with the enthusiastic youth that he encouraged Mayr to publish the observation in what was to become his first scientific paper.
By the time Mayr was twenty-one he had received both a degree in medicine and a Ph.D. for studies in avian biogeography. His medical diploma, however, would only gather dust, for by twenty-three he was already employed at the Museum für Naturkunde and about to embark on the greatest adventure of his life—a two-and-a-half-year-long expedition to Melanesia, initially as one of Lord Rothschild’s collectors.
Walter Rothschild is surely one of the most extraordinary figures of the early twentieth century. He is justly famous as the addressee of the Balfour Declaration, for he steadfastly believed in the “government dedicated to social and national justice” which that paragraph sought to establish in Palestine. His role in the family banking business, however, is less obvious. Between the ages of twenty-one and thirty-nine, at his father’s behest, Walter spent every working day at the bank’s headquarters in New Court, London. He arrived punctually at nine and departed on the stroke of five, yet there is not a scrap of evidence to indicate that he actually did anything there—no sign of a deal brokered or loan approved, nothing so much as a paper bearing his signature. The reason for this seems to be that all the time Walter was confined to that gilded cage, his mind and heart were soaring with the birds. Natural history, and ornithology in particular, was Rothschild’s lifelong passion and he devoted his entire income to it.
Between 1890 and 1931 Walter amassed, on the family estate at Tring in the Chiltern foothills, the greatest museum collection ever held in private hands. Among …