Quite a few Siskins knocking about at the moment. Last time this happened I had birds to/from Norway, Highland, Merseyside and Herefordshire in the garden; bugger all so far this winter. This lot are showing the usual variability in post-juvenile moult though, anything from 1-8 old greater coverts on the first winters.
A couple of pics from this morning, top adult, bottom 2nd cal year. Note the differences in the tertials, greater coverts (GCs 1-5 and 10 retained juv feathers in the bottom pic), alula, median coverts (outermost is a retained juv feather in the bottom pic), primary coverts, primaries and secondaries.