Evolution, Taxonomy and Systematics
The evolutionary relationships of the scops and screech owls are not entirely clear. What is certain is that they are very closely related; they may be considered sister lineages which fill essentially the same ecological niche in their allopatric ranges. A screech owl fossil from the Late Pliocene of Kansas (which is almost identical to Eastern and Western Screech Owls) indicates a longstanding presence of these birds in the Americas, while coeval scops owl fossils very similar to the Eurasian Scops Owl have been found at S'Onix on Majorca. The scops and screech owl lineage probably evolved at some time during the Miocene (like most other genera of typical owls), and the three (see below) modern lineages separated perhaps roughly 5 million years ago. Note that there is no reliable estimate of divergence time, 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. Like almost all scops and screech owls today, their common ancestor was in all probability already a small owl, with ear tufts and at least the upper tarsus ("leg") feathered.
However that may be, the hypothesis that the group evolved from Old World stock is tentatively supported by cytochrome b sequence data. The screech-owls also have a different placement of the procoracoid (less of an anterior incline) and coracoid bones compared to other New World owls.
Read more about this topic: Screech-owl