“I am posting an adult [Common Myna (Acridotheres tristis tristis)] who had juveniles in attendance. The adult was well groomed (above left) and one juvenile’s plumage seemed appropriate (below), but the other juvenile seemed to have an early onset of the adult head moult (above right and bottom). I have yet to see a juvenile with loss of head feather so early as in above right that the back of the head is also affected.
“There have been different opinions as to the cause of this loss of head feather in adults. The majority opinion is that it is a form of moulting. I hold the opinion that it is some form of disease (my medical background and it is quite grotesque).
“Now seeing a juvenile with it so early I wonder if there is a genetic component to this problem (despite the visible adult parent being OK at this point in time).”
Dato’ Dr Amar-Singh HSS
Ipoh City, Perak, Malaysia
12th May 2013