In the earlier days, popular bird publications such as field guidebooks treat the Buteo buzzards occurring in Singapore simply as Common Buzzard Buteo buteo.
Three publications do not list any subspecies:
- Birds of Singapore (Lim & Gardner, 1997)
- Birds of West Malaysia & Singapore (Jeyarajasingam, 1999)
- Annotated Checklist of the Birds of Singapore (Wang & Hails, 2007)
Birds of Thai-Malay Peninsula vol 1 (Wells, 1999) and Birds of Southeast Asia (Robson, 2000) also treated these buzzards as Common Buzzard Buteo buteo, listing vulpinus and japonicus as the subspecies. The Avifauna of Singapore (Lim, 2009) treated these buzzards as Common Buzzard Buteo buteo, listing japonicus as the subspecies for Singapore.
Now, for the splits.
Birds of Southeast Asia, 2nd edition (Robson, 2008) split the buzzards into two species:
- The Common Buzzard Buteo buteo, with vulpinus as the subspecies occurring in Southeast Asia.
- The east Asian population as Himalayan Buzzard Buteo burmanicus, as the other species occurring in Southeast Asia.
Birds of Singapore (Yong, et al, 2013) also split the buzzards into two species, but in a different manner:
- The Common Buzzard Buteo buteo, with vulpinus as the subspecies occurring in Singapore.
- The east Asian population is given a different treatment, as Eastern Buzzard Buteo japonicus, as the other species occurring in Singapore.
No worries, Birds of the Indonesian Archipelago (Eaton, et al, 2016) lumped the buzzards back into Buteo buteo, using the name Eurasian Buzzard. They listed vulpinus, refectus & burmanicus as the subspecies occurring in Southeast Asia, commenting that “Species taxonomy confused, but substantial overlap in morphological characters and extremely limited mtDNA divergence advocate subspecific status of these allopatric breeding forms.”