The Iberian Chiffchaff has only recently been split and is nearly impossible to tell apart from a "normal" Chiffchaff in the field if one doesn't have the luck to hear their call or song. The supercilium is bright yellow in front of the eye and there is a slightly longer primary projection, but the former can be affected by the light and the latter is to all intents and purposes only measurable in the hand. The call is similar to that of a Common Chiffchaff, but is slightly higher pitched and faster, and often with a small trill at the end. Normally sings from high in the canopy and thus can be difficult to find.
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