The Ferruginous Hawk, a breeding bird endemic to North America, was named Falco ferrugineus in 1838 by H. Lichtenstein, curator of the Berlin Zoological Museum. The type was collected by F. Deppe near present day Monterey, California. In 1844 G.R. Gray of the British Museum assigned the name Buteo regalis to a Ferruginous Hawk specimen of unknown origin, but perhaps donated to the museum by John Phillips, a renowned British geologist. The species was known as Falco (Buteo) ferrugineus until the 1920s when it was discovered that this epithet was occupied. The next name in priority was Gray's Buteo regalis, which then became valid. The species has been known by a number of common names. Even though any reference to the rusty brown markings on the otherwise white plumage is no longer part of the species specific name, the Ferruginous Hawk continues to be the most frequently used common name.
Woffinden, Neil D.
"History of the naming of the Ferruginous Hawk,"
Great Basin Naturalist: Vol. 59
, Article 3.
Available at: https://scholarsarchive.byu.edu/gbn/vol59/iss3/3