I did a search of Berksbirds on February and last dates in the database and found the results rather interesting;
26th 2001 - Theale male
22nd 2002 - Burghfield GP's male
24th 2008 - Dorney Wetlands male
15th 2009 - Dorney Wetlands male
26th 2011 - Dorney Wetlands male22nd 2012 - Bray male
12th 2012 - Rowneys/Woolhampton male
25th 2016 - Dinton Pastures male
26th 2017 - Dinton Pastures male
My point here is this, what is it about the DP bird that makes this more escapee? It leaves the same time as more or less all other males and arrived in 2016 at the same time as a female at Theale.
I trust the rarities committees will be looking at all the evidence when the sum up their conclusions about DP Ferruginous Ducks. Assumptions about having a ring on it's leg alone will not cut it as the only deciding factor, as far as I am concerned.