While Allen, Kellogg and Tanner were in the Denver area recording birds in 1935, they were hosted by Dr. Robert J. Niedrach.
Niedrach and Robert B. Rockwell coauthored Birds of Denver and Mountain Parks in 1939.
The Denver Museum of Natural History (later changed to the Denver Museum of Nature and Science) employed Niedrach from 1913 until his retirement in 1970. He was a field naturalist who became the museum’s curator of birds. Niedrach was also a collector, taxidermist and preparator. He worked closely with Alfred M. Bailey, the museum's director from 1936 to 1969.
Bailey was a pioneering bird photographer and cinematographer noted for his fieldwork. Bailey and Niedrach worked on several projects together. In 1951, they coauthored Stepping Stones across the Pacific, in 1953, The Red Crossbills of Colorado, in 1965, the two-volume Birds of Colorado and in 1967, they published Pictorial Checklist of Colorado Birds: with brief notes on the status of each species in neighboring states of Nebraska, Kansas, New Mexico, Utah and Wyoming.
The Denver Museum of Natural History (later changed to the Denver Museum of Nature and Science) employed Niedrach from 1913 until his retirement in 1970. He was a field naturalist who became the museum’s curator of birds. Niedrach was also a collector, taxidermist and preparator. He worked closely with Alfred M. Bailey, the museum's director from 1936 to 1969.
Bailey was a pioneering bird photographer and cinematographer noted for his fieldwork. Bailey and Niedrach worked on several projects together. In 1951, they coauthored Stepping Stones across the Pacific, in 1953, The Red Crossbills of Colorado, in 1965, the two-volume Birds of Colorado and in 1967, they published Pictorial Checklist of Colorado Birds: with brief notes on the status of each species in neighboring states of Nebraska, Kansas, New Mexico, Utah and Wyoming.