Ringed Plovers - hiaticula and psammodrama

Good numbers of Ringed Plovers are passing through at the moment with I've seen sizable flocks seen at Horton's Nose, Rhyl (30+) and Ynys las, Ceredigion (60+). I've been interested in the subtle differences in plumages between the birds, with some being big, pale and in full breeding attire, while others are smaller, slimmer, darker and rather grubby looking (winter plumage / moulting). According to the date (April / May), Ringed Plovers passing through Wales at this time could be (or even should be) on their way to northern Europe i.e. feno-scandanavia, making them of the race 'psammadrama'. They use to be known as 'tundrae' Ringed Plover, but birds now known by this name are thought be belong to the 'eastern' races of Ringed Plover.

A nominate British breeding 'hiaticula' Ringed Plover in front of a presumed 1st w Scandanavian 'psammodrama' Ringed Plover

Our nominate race 'hiaticula' should be on their breeding grounds by now and a number of examples were seen on the beaches of mid wales and along the eastern Conwy coast. They are fairly bulky, pale looking birds and will have moulted into their present plumage last August / September.

A fairly standard nominate bird - bulky, pale and in full breeding atire.

The race 'psammadrama' on the other hand will either still be in winter plumage or moulting into summer as they go through a complete body moult in spring (unlike our nominate race). These birds tend to be slightly smaller, slimmer and darker.

A presumed 'northern' Ringed Plover - smaller, sleeker and darker than our nominate. Also signs of spring moult - forehead and breast band.

A nominate (hiaticula) Ringed Plover in the forground (out of focus but still enough to see features), with two presumed northern 'psammadrama' Ringed Plover in the background - the left hand bird is still in winter plumage (brown where we would expect black and bill is just starting to change to orange).

I watched the birds very early in the mornings so the pictures are not good at all, but hopefully you will see what I'm trying to get at.

I might be wrong, but by looking carefully at these flocks over the last week, it seems to me that a good proportion of birds seen along our coast at this time of year are indeed 'psammadrama'. I would also think that the reverse happens in autumn when our Ringed Plover flocks build up again. Any one else got any thoughts, experience or opinions?......feel free to tell me I'm talking rubbish :-)