in 1933, then pursued doctoral work at the University of California, Berkeley, under Joseph Grinnell, earning a PhD in 1937.

Aside from four summers as a naturalist at Grand Canyon National Park, Behle spent the majority of his career as a professor at the University of Utah, where he worked from 1937 until his retirement in 1977, and continued to perform research as professor and curator emeritus.

[3][5] Behle's contributions to ornithology include some 140 papers on bird distribution and taxonomy, and the description of several subspecies (geographic races), including the western purple martin (subspecies Progne subis arboricola) and a race of slate-colored fox sparrow.

Behle's 1990 book Utah Birds: Historical Perspectives and Bibliography focused the history of ornithology in Utah from 1776 to modern times, with biographical accounts of collectors and researchers, amateur and professional alike.

[6] UC Berkeley professor Ned K. Johnson called it "the most detailed ornithological history of any extensive region of North America.