Ten years ago in 2014, I wrote about the possibility of the resident scops owl in Singapore being a distinct species on its own. The conclusion by our local ornithologist was that it’s probably not, and more work needs to be done to further understand the relationship and territorial delineation between all the closely related (Sunda/Collared/Indian) Scops owls.

While updating my own Singapore bird checklist recently, I noticed that there was an update that I initially missed out. In turns out that cnephaeus subspecies from Malaysia and Singapore has been reassigned from Sunda Scops Owl to Collared Scops Owl. A closer scrutiny showed that the paper that prompted this revision was published in the Avian Research journal titled  “Continent-wide vocal leapfrog pattern in Collared Scops Owls obfuscates species boundaries“, co-authored by Meng Yue Wu and Assoc Prof. Frank E. Rheindt. The latter being the same person I quoted in the original article that many years ago!

You can find versions of that paper here and here.

They did the work using publicly available song recordings from xeno-canto. The research paper is interesting and some of the conclusions drawn are also noteworthy. Please go and read. I’ll copy a long paragraph here for the most pertinent one to our local scops owl’s species assignment:

Many tropical Asian bird species complexes are divided into an equatorial rainforest species centred around the western Indonesian Archipelago and a closely related monsoon-forest inhabiting species from the Asian mainland (Eaton et al., 2021). Whenever birds display such a biogeographic constellation, the Sundaic species virtually always extends north to the Thai-Malay Peninsula and reaches its northern limit at the Isthmus of Kra, where the range of the continental monsoon species takes over. Owls of the Collared Scops Owl complex were long thought to follow this geographic pattern, with cnephaeus from the Thai-Malay Peninsula invariably assigned to O. lempiji from Indonesia. However, our bioacoustics-based reassignment of cnephaeus to O. lettia suggests that these scops owls defy this biogeographic pattern, as the continental O. lettia extends south all the way to Singapore.

I’m not interested in editorialising too much, but I think the best lessons I have learned from this:

1. Crowd-sourced birding information (photos, videos, audio recordings, GPS coordinates) continue to be useful tools in doing real and interesting science.
2. Unlike what most may imagine, scientific advancement need not always be about expensive tools and techniques; ideas are equally important.
3. Empirical data lead us to sometimes unexpected conclusions, but that’s rather characteristic of scientific progress.