Joseph Grinnell, the Director of the Museum of Vertebrate Zoology, University of California, Berkeley, in the spring of 1908, and collected waterbirds for Grinnell's studies of California birds. Before long, Beck was offered even more money by Dr. Leonard C. Sanford, of New Haven, Connecticut, to collect birds in Alaska for the well-known ornithologist Arthur Cleveland Bent, who was collecting for his studies of “The Life Histories of North American Birds.” He did much of the field work with the young Alexander Wetmore, who had recently graduated from college. Brewster-Sanford Expedition to South America In 1912, Dr. Leonard Cutler Sanford proposed a larger two-year expedition (that ended up taking five years) to South America for Rollo and Ida, and financed by Mr. F. F. Brewster. They traveled up into lakes and highlands of the Andes, along the coast, and out at sea to the Falkland Islands and Juan Fernández Islands, sailed around Cape Horn in a 12-ton cutter, and up into the Caribbean. This work and these collections proved invaluable to Robert Cushman Murphy, who later published “The Oceanic Birds of South America” based in part on the Brewster-Sanford Expedition collection of Rollo Beck. Whitney South Seas Expedition In 1920 Beck was contacted by Dr. Sanford who proposed an extended South Pacific expedition. The fieldwork was funded by Harry Payne Whitney of New York, and the specimens were bound for the American Museum of Natural History. This became the longest and greatest of all Beck's expeditions and, as with the "Academy" expedition of 1905–06, he was joined by many other accomplished biologists and field collectors with complementary skills, including E. H. Quayle, J. G. Correia, Dr F. P. Drowne, Hannibal Hamlin, Guy Richards, Ernst Mayr, E. H. Bryan Jr., and others. Beck left the expedition in 1929, after sailing through the Pacific, from Tahiti to New Guinea to New Zealand and visiting hundreds of islands between. Rollo and Ida Beck returned to the California in 1929 with over 40,000 bird skins and a large anthropological collection. This expedition remains to this day the most comprehensive survey and study of birds in the south-west Pacific islands, and has been written up in dozens of important scientific monographs of birds. The specimens residing at the American Museum of Natural History in New York City form the most comprehensive collection of Pacific birds anywhere. Rollo and Ida Beck retired to the northern California