“There is always some madness in love. But there is also always some reason in madness.” ― Friedrich Nietzsche
Everybody knows the chiffchaff world is a complete mess. Among all the fucked up chiffchaffs we’ve caught this autumn (including tristis, tristis-like, abietinus, abietinus-like, collybita and collybita-like), my favorites are still a couple of “green chiffchaff” we caught two weeks ago. Both of them showed what in my opinion are Iberian chiffchaff characters, although the only call I heard from one of them was perfectly normal for a Common. Of course I am not that mad to claim 2 Iberian chiffchaffs ringed the same day in autumn in southern Sweden, but, from an Iberian point of view, it’s interesting to know that these birds do exist and therefore we should be cautious when it comes to identify an Iberian chiffchaff in the field without vocalizations.
The birds showed pale upperparts, very clean, without any hint of grey nor brown and with some lemon-green tinges instead. The underparts were also very clean, with blurred yellow in the undertail coverts and yellow stripes in the breast. There was not a frontier between the cheeks and the throat, giving an open-face impression, what is meant to be a reliable key feature for Iberian. Furthermore, the eyebrow was greener above and in front of the eye, what creates a patchy impression, just as in an Iberian.
Structurally, they looked long, I wouldn’t say abietinus-shaped, but there was something on them that reminded me as such. However, the wing-lengths were 58 and 59 respectively, within collybita range and far from the >61 usual in the abietinuswe are catching. Moreover, P2 equalled P7 in on of them, whereas the other showed the usual P2=7/8 for Common Chiffchaff. In the photo below it’s possible to compare the structure and coloration of a typical abietinus (left), a typical collybita (centre) and one of the two tricky birds caught (right).
Since a picture paints a thousand words, the photo below was taken in Spain in April 2009. It shows an Iberian chiffchaff (in the left) together with a collybita Common chiffchaff. If you compare this photo with the one taken in Sweden, you’d probably find some similarities.
However, there are some differences. The Iberian is brighter and more saturated green-yellow, especially in the scapulars and flight and tail feather edges. Also, the bill is longer and thinner, with a characteristic shape ended in a subtle hook, whereas the Swedish bird’s got a bolder bill that gives a more powerful impression. It’s worth to keep in mind that the Iberian chiffchaff of the photo above was caught after the pre-breeding moult. It’s worth or maybe it’s not, because, to be honest, I don’t know the effects of the pre-breeding in these bloody weird chiffchaffs. My hope is that they become greyer, but my feeling (based on photos of spring birds from Israel) is that they become greener. If so, field identification of Iberian chiffchaff based on plumage characters is sadly still in standby.