This, in itself, is also advantageous, because the vast majority of mutations that manifest themselves as changes in appearance, functionality or behavior, are disadvantageous.
All other common owls in this species range also live off of similar rodent prey but direct competition is obviously disadvantageous to the screech owl.
Conversely, multiple mating can be disadvantageous for females because it reduces foraging efficiency and increases the chances of predation and parasitic infection.