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Sand Martin ageing tutorial request! (1 Viewer)

SteveMM

Well-known member
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.
 

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Steve,

I don't know about moult in eastern populations but riparia has a post juvenile moult mid July-end Sep which typically includes lesser, median and innermost greater coverts and, exceptionally the innermost primary is moulted. The complete moult starts later in (late Oct) Nov and is completed mid Mar (early Apr).

In adults the moult is occasionally started in summer and suspended (Jun-Sep) and then completed Oct-early Dec.

The moult of your birds looks better for adult, that is assuming the moult timing is the same as western populations which may not be the case.

Grahame
 
Steve,

I don't know about moult in eastern populations but riparia has a post juvenile moult mid July-end Sep which typically includes lesser, median and innermost greater coverts and, exceptionally the innermost primary is moulted. The complete moult starts later in (late Oct) Nov and is completed mid Mar (early Apr).

In adults the moult is occasionally started in summer and suspended (Jun-Sep) and then completed Oct-early Dec.

The moult of your birds looks better for adult, that is assuming the moult timing is the same as western populations which may not be the case.

Grahame

Thanks a lot for the quick and detailed response, Grahame; it is much appreciated.

Without knowing at all for sure, I would be surprised if moult in ijimae were not skewed towards the end of these periods given that it generally stays colder in East Asia for longer in spring. I think I can safely eliminate juvenile ijimae from my reckonings for this individual anyway.

Steve
 
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