Not a question about a ring but I think one for a ringer!
I originally thought that this bird would have to be an adult due to the active moult in the primaries, but have since read that juvenile Sand Martin has a complete post-juvenile moult. The unmoulted remiges and rectrices seem to have that kind of 'juvenile brown' look to them to my eye, but at that point the limits of my expertise have already been reached!
So: Can this bird be correctly aged? And at what point post-fledging does a juvenile Sand Martin begin its post-juvenile moult (of its primaries)? Should this occur at a later date than this?
I should also add that, in Taiwan, I'm probably more in the range of Pale Martin here, and am not at all sure which one of the two this bird actually is. Photo taken last week (23/9), Tainan County, SW Taiwan.
I originally thought that this bird would have to be an adult due to the active moult in the primaries, but have since read that juvenile Sand Martin has a complete post-juvenile moult. The unmoulted remiges and rectrices seem to have that kind of 'juvenile brown' look to them to my eye, but at that point the limits of my expertise have already been reached!
So: Can this bird be correctly aged? And at what point post-fledging does a juvenile Sand Martin begin its post-juvenile moult (of its primaries)? Should this occur at a later date than this?
I should also add that, in Taiwan, I'm probably more in the range of Pale Martin here, and am not at all sure which one of the two this bird actually is. Photo taken last week (23/9), Tainan County, SW Taiwan.