Every now and then I stumbled upon an eggshell in my garden (above). The shell is light blue on the outside and white on the inside. Obviously it is from the egg of the Javan Myna (Acridotheres javanicus).
It is common knowledge that incubating birds remove eggshells immediately after hatching and dispose them some distance away. Fresh eggshells lying below nests will attract predators, especially when the white inner surface reflects light.
I have personally observed such behaviour in the Zebra Dove (Geopelia striata) that nested in a tree along the road outside my house LINK. I have also recently witnessed the removal of the eggshell in the nesting of a pair of Spotted Doves (Streptopelia chinensis) in a tree inside my garden LINK.
In both cases I only managed to see the bird flying off with one half of the eggshell. The other half must have been removed earlier or later. In the case of the eggshell of the Javan Myna, I have yet of encounter both halves of the shell in the garden at around the same time. It is most probable that the different halves were disposed in separate locations.
Although I have encountered the shells in my garden a number of times, I have yet to locate the nesting of Javan Mynas in and around the garden. These birds nest in holes found in trees, under roofs and even on the top of palms. Unfortunately there is limited information on the nesting behaviour in the literature although this is a very common species – another example of a common species being ignored by wirdwatchers LINK.