For most of the 20th century, this genus was merged with the Old World scops owls in Otus, but nowadays it is again considered separately based on a range of behavioral, biogeographical, morphological, and DNA sequence data.

They also possess well-developed raptorial claws and a curved bill, both of which are used for tearing their prey into pieces small enough to swallow easily.

The distinctness of many species of screech owls was first realized when vastly differing calls of externally similar birds from adjacent regions were noted.

Note, no reliable estimate of divergence time is known, as Otus and Megascops are osteologically very similar, as is to be expected from a group that has apparently conserved its ecomorphology since before its evolutionary radiation.

[9] While late-19th-century ornithologists knew little of the variation of these birds, which often live in far-off places, with every new taxon described a few differences between the Old and New World "scops" owls became more and more prominent.

Subsequently, the highly apomorphic white-throated screech owl of the Andes was placed in the monotypic genus Macabra in 1854.

The third edition of the American Ornithologists' Union (AOU) checklist in 1910, placed the screech owls back in Otus.

In 1988, attempts to resolve this were made by re-establishing all those genera split some 140 years earlier at subgenus rank inside Otus.

[10] Still, the diversity and distinctness of the group failed to come together in a good evolutionary and phylogenetic picture, and until the availability of DNA sequence data, this could not be resolved.

In the mid- to late 1990s, preliminary studies of mtDNA cytochrome b across a wide range of owls found that even the treatment as subgenera was probably unsustainable and suggested that most of the genera proposed around 1850 should be accepted.

Its distinct coloration, approximated in the southern whiskered screech owl (Megascops trichopsis mesamericanus), is thus likely the result of strong genetic drift.