Mandarin at Rowsley but no sign of the Dusky Thrush

I'm not clear on the movement of Mandarin in the Darley Dale area. Numbers peak during the breeding season and late summer then rapidly decline in the autumn but then start to increase again in the late winter. There is a significant increase in birds at Linacre Reservoir in the early winter so perhaps our birds go there for a few months?
I check the Mallards at Peak Village for Mandarin but haven't seen any for at least a month but today there were at least 6 males and 3 females. All looking very smart.

Mandarin -male

I spent a couple of hours at Beeley this morning but no sign of the Dusky Thrush. My last sighting was on Wednesday  morning (14th at 9:20) and it looks like this may be my final photo our our rare Siberian visitor.

Dusky Thrush