Pale-bellied Brent Goose ageing

Pale-bellied Brents seem to be easier to age at a later date in the winter than Dark-bellied birds with the pale tipped coverts retaining their white tips -- the local flock has 8 juveniles and 6 adults but both Dark-bellied birds are juveniles -- two wildfowlers were setting up in the field next to where these were today -- lets hope they know what they are shooting at!