There are several birds in the field which some birders might just brushed off as another common bird. Yet these so called common birds do provide some intriguing features and good debate topics among some senior/season birders until today. One of these common birds which has until now posed some un-answered questions are the "Acridotheres fuscus"(Jungle Myna) and "Acridotheres javanicus"(Javan Myna). It was said that the latter (A.javanicus) have migrated from south of Peninsular Malaysia and displaced or genetically swamped the native populations of (A.fuscus) further north (Allen J, 2010). This post was specially written in relation and with reference to an article titled "A Freak of Nature: Aberrant Myna" by Allen J which appeared in "Suara Enggang", Vol.18, No.1 (Jan - Feb) 2010.
The above are a flock of "A.fuscus" grazing one of the fields at Kampung Siam in Kedah.
Here is a closer look at the Jungle Myna (A. fuscus). According to Allen J & Pearson (2012), the iris of a Jungle Myna is conspicuously yellowish while those of A. javanicus in its genetically pure form is white. From the pictures above you could see that all the A. fuscus' irises were indeed yellowish in color.
Javan Mynah
The above photos of A. javanicus clearly depict its genetically pure state of iris which is white. These photos were taken in Cheras, KL.
However according to Allen J (2010), it has been noted that some A. javanicus in KL/PJ which was once a stronghold of A. fuscus, are without dark bases to the bill but with yellow irises and brown tinged plumages, especially on the mantle.
The above is a photo of A.javanicus which was taken in KL. Note its yellow iris but lack of dark bases to its bill as well as its brown tinged plumage.
Here is another A.javanicus taken at FRIM, Kepong.
This Javan was spotted recently at Raptor Watch 2012 - Tanjung Tuan near the light house area.
Allen J (2010) further revealed that in terms of morphology (i.e. the shapes of the body, head, bill and crest length and shape) as well as their calls, there are close similarities between A.fuscus and A.javanicus. The only noticeable difference observed between them is in their behavior whereby A javanicus are said to be more opportunistic and aggressive. From my own field observations i do concur with this statement. Jungle mynas on the other hand were a bit more skittish.
As there are already some genetically identical birds which carry the genes of both species as shown in the photos above, one may now need to go further than to look at just its irises or the base color of its bill. Based on my own experience, one other features which one could look at is perhaps the color of its head whereby A. fuscus seem to have a more blackish head with a contrasting greyer brown body as well as a smaller looking iris.
HAPPY BIRDING !!
