There is rufous spotting on the breast with black anchor marks. The juvenile of both colour phases is similar to the adults, but the indistinct stripes and bars are more patterned, with many feathers tipped with white. The Western Screech Owl is likely to be confused with the Eastern Screech Owl and Whiskered Screech Owl. Western and Eastern Screech Owls only occur together locally in eastern Colorado and southern Texas. Western and Whiskered Screech Owls only occur together in southern Arizona and Mexico.
Wings are broad and the head is held tucked in giving a flying bird a stubby appearance.
Weights of different subspecies vary widely. It is given by the male during the mating and nesting seasons, but also during the autumn and winter. This call is primarily territorial in nature. A secondary song is a double trill of rapid bursts. Western Screech Owls are nocturnal, hunting from dusk to dawn, before retiring to daytime roosts.