"Previously we recognized two subspecies of Barn Owl from Sub-Saharan Africa, and recognized each of these as a monotypic group: Barn Owl (African) Tyto alba affinis, and Barn Owl (Bioko) Tyto alba poensis. The population of Bioko, while still very poorly known, apparently is not diagnosably different from populations on mainland Africa, and so only a single subspecies should be recognized in Sub-Saharan Africa (Bruce and Dowsett 2004). As poensis Fraser 1843 is an older name than affinis Blyth 1862, however, poensis now applies to all Barn Owls in the region. The group Barn Owl (Bioko) is deleted; the scientific name of the group Barn Owl (African) changes to Tyto alba poensis; and the range of poensis is revised from "Bioko (Gulf of Guinea)" to "Sub-Saharan Africa (including Bioko, Zanzibar, and Pemba), the Comoro Islands, and Madagascar"."

https://www.birds.cornell.edu/clementschecklist/updateindex/october-2022/updates-corrections-october-2022/