On 14 July I stumbled upon a calling Iberian Chiffchaff (ca 45th record) in my hometown The Hague. Since calling birds are probably overlooked in The Netherlands, I wrote a short note on their calls.
Upper and lower pic by Gerjon Gelling
Quite amazing that I was lucky enough to find two of these birds within 3 months! Ageing this bird turned out to be straightforward. In July juveniles are very fresh, while adults are completely worn and usually in their post-breeding moult - like this bird. So as expected (since a juvenile in July would be sensational), this was an adult bird.
On the 15th, I managed to get some shots, and my friend Gerjon got much better ones. This allowed us to have a better look at its plumage. Well, this bird wasn't very pretty! It was worn and moulting body (there was even bare skin visible on the throat) and wing feathers which, in passerines, are moulted symmetrically in both wings. See pic:
I count 5 visible primaries. The very short P1 cannot be seen in this shot. The shot is just not good enough te be entirely sure, but it seems to be missing 4 primaries. P? is a growing feather and I don't know which one it is (since the inner one is moulted first, this could be P10). There's also a growing inner secondary. So it's hard to judge what's precisely going on, and it's impossible to see if this bird is perhaps in its 2nd cy (see this article), but it's moulting remiges, allright. Hence, this can never be a juvenile!
Btw, here's a typical call of the bird (14 July 2017):