The ID of Athene noctua sspp identity in field guides has relied on morphological and plumage descriptions in many earlier sources. However, Pellegrino et al 2020 found an absence of clear-cut differences between sspp and a huge variation of morphological and colour patterns between individuals collected within any geographical area; no ssp could safely be identified on morphological data. As a consequence, the geographic distributions allotted to most subspecies are now suspect, as are sspp IDs.
Sorting out these uncertainties will require a host of genetic techniques. In the meantime, statements based on current understanding should carry a caveat! Perhaps Irene Pellegrino has further genetic research of this species on her 'to do' list?
MJB
Pellegrino, I, M Cucco, E Calà, G Boano and M Pavia. 2020. Plumage coloration and morphometrics of the Little Owl Athene noctua in the Western Palearctic. J. Orn. pp11 doi.org/10.1007/s10336-020-01792-7 (attached)