Historical samples inform conservation efforts to prevent extinction.
The “Javan Pied Starling” is extinct in the wild. This particular population, formerly located on the island Java, is part of the Asian Pied Starling (Gracupica contra) species complex and has been considered a distinct species by some ornithologists. Currently, it is treated as a subspecies (jalla), alongside four other subspecies (contra, sordida, superciliaris, and floweri). Regardless of its taxonomic status, the IUCN Specialist Group for Asian Songbird Trade considered it one of the top 10 taxa warranting immediate conservation action to prevent its extinction. Captive populations of the Javan Pied Starling could be the starting point for a breeding program. There is, however, an issue with these captive birds: jalla individuals are often crossed with other subspecies (especially floweri from Thailand). This raises the question whether there are still “pure” Javan Pied Starlings around. A recent study in the journal Evolutionary Applications tried to solve this mystery by returning to the situation before hybridization in captivity.
Before we can assess the degree of hybridization in captivity, we need to know whether the Javan Pied Starling is a separate taxon. It might look different from the other taxa – with its extensive deep-orange skin around the eye – but is it also genetically distinct? Pratibha Baveja and her colleagues sequenced the DNA of several historical samples (ranging from 1878 to 1983) and compared the genetic make-up of the different subspecies. Their analyses revealed three distinct genetic groups: the taxa contra and superciliaris clustered together whereas jalla and floweri formed their own clusters (samples for sordida were not included). This arrangement was further supported by mitochondrial DNA, showing each subspecies as a separate evolutionary line. The most relevant finding for this blog post is that the Javan Pied Starling is indeed a distinct taxon. The authors even propose to treat it as a separate species.
But what about the captive birds? To figure out whether there are still “pure” Javan Pied Starlings in captivity, the researchers compared the DNA of several individuals from the Bali Bird Park (Indonesia) and the Jurong Bird Park (Singapore) with the historical samples. The captive individuals showed the same genomic profile as the historical samples, suggesting a lack of admixture from other other subspecies. These birds can thus be used to start a breeding program to save this species from extinction. There is still hope for the Javan Pied Starling.
Baveja, P., Garg, K. M., Chattopadhyay, B., Sadanandan, K. R., Prawiradilaga, D. M., Yuda, P., Lee, J. G. H. & Rheindt, F. E. (2021). Using historical genome‐wide DNA to unravel the confused taxonomy in a songbird lineage that is extinct in the wild. Evolutionary applications, 14(3), 698-709.
Featured image: Asian Pied Starling (Gracupica contra) © Sai Adikarla | Wikimedia Commons