Age determination in Penduline Tits Rerniz pendulinus has largely been based on the colour contrast that young birds show between moulted and unmoulted greater coverts. However, in Southern Europe some young birds are likely to moult all the greater coverts. The usefulness of the alula and tertials as on additional ageing criterion was tested in a sample of 156 wintering Penduline Tits trapped in north-east Spain. Young birds showed an unmoulted alula, as opposed to the moulted one of adult birds. No occurrence of tertial moult was deteded. A smoll proportion of young birds (5%) moulted all of their greater coverts, but not the central feather of the alula. Therefore, partial moult of the greater coverts cannot be used as the only ageing criterion in Southern Europe, and should be supplemented by examination of the alula.
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