Where have all the Greenfinch gone?

Sightings of Greenfinch at our garden sunflower seed feeders in Blakeney have been very few this year although I have heard several flying over  towards the south on occasions.  Good numbers (of any species which flock to roost) can reveal their destination if one is lucky enough to see their regular flight lines.

Sad, but not surprising to note that Greenfinch numbers have collapsed since 1971 at Walsey considering all the dire warnings about their wider  decline. I did my ringing training in the early 60s at a big Greenfinch roost in a woodland Rhododendron patch near Oxford, which was faithfully populated with over 100 birds for a number of years at that time.
Probably not enough numbers these days, but I wonder if it would be possible  to triangulate any late afternoon flights lines to see where the Cley Square birds roost. I suggest somewhere like Bayfield or Holt Hall which has extensive Rhodo patches might fit the bill or indeed further afield such as Stody. Do stick a reply on the Forum if you have seen late afternoon Greenfinch fly overs ! Location, direction and number is all that would be needed, apart from the slim chance of seeing Greenfinches this winter?

PS – What a joy to be hearing a bit of birdsong again 0- Happy New Year.