The bird had undergone a pre-breeding moult (but, apart from a single flank feather, there didn't seem to be any active moult); all three tertials were new as were the inner two greater coverts. GC9 had an almost ash-grey border to it; the border of GC10 was tinged slightly more olive. The bird's primary coverts seemed to be juvenile feathers (loose and 'frayed' at the tip), as did the outer eight greater coverts. The large alula was rather faded and brown; the flight feathers showed a rather obvious growth bar, equal distance from the feather tip all along the primaries and secondaries.
Overall, the bird should have been a 2cy. Indeed, iris colour agreed with that assesment... but the plumage was so fresh! Fresh-looking even for a 3+cy, actually. Whilst it seems nice and neat to age the bird a 2cy, it's far better to be imprecise and correct than precise and wrong, hence we left it unaged.
In terms of where the bird came from; the first thing I did when I took it out of the net was check for wingbars, then check the wing formula — it was that sort of an interesting-looking bird. The wing formula and, back at the ringing lab, measurements both fitted Common Chiffchaff but didn't seem to help in determining a subspecies (though a winglength of 58 mm would be at the bottom end for abietinus and the top end for tristis). The bird was cold on the head and back but only really grey on the nape/neck, tertials and upper tail coverts. The back and rump were tinged green and there were lines of green running through the mantle. The flight feathers showed greenish fringes.
The underside was streaked yellow.
The same yellow tones were also present in the supercillium.
The legs were dark but not black and the long-looking bill was pale at the base.
This photo, which I've left unsharpened, shows the colour tones quite well:
For comparison, here's a "normal" Chiffchaff; photo taken 20 minutes later.
A splash of colour was added by two male Yellowhammers ringed and a ringed adult male Common Rosefinch. Sadly, the rosefinch managed to avoid the nets and was only seen briefly so I guess we'll never know where it came from.
Three Hawfinches were briefly in the lighthouse garden.
After ringing we headed up to the harbour road where we found a pair of agitated Avocets on the cycle path next to the road. Closer inspection revealed peeping coming from the long grass: chicks!
We moved back, donned our fluorescent jackets, grabbed our lollipops, then waited for the chicks to cross; a bit of traffic control as they appeared ensured all four chicks got safely to the other side.
We finished the day with a chill 'n' grill at Knösen— several Icterine Warblers were singing and at least one Cuckoo was about.