An Interesting Chiffchaff

This Chiffy was ringed today on the Teifi Marshes Reserve.  It is very different to/from the usual ones we get here.

* On the face, back and upper wings the overall colour is markedly paler and greyer than the usual olive-brown.

* On the belly, flanks, and under-wing there is no sign of the usual yellow or green tones, the only suggestion being a few yellowish-buff feathers in the inner axilliaries.

* The complete white eye-ring stands out particularly prominently.

This is a bird fledged this year - it has four unmoulted juvenile greater coverts on each wing. Biometrically it is indistinguishable from a 'normal' Chiffchaff, and it didn't call.  Did it come over with the Yellow-brows?  We'll probably never know.