Phylloscopus trochilus - spring

Willow Warbler


Due to complete pre-breeding moult in both age classes, ages are not separable. Rare occasions of single ’forgotten’ feathers are known, and the status of such (worn juvenile contra worn post-breeding) may serve as a help. Colour of iris is of little use owing to individual variation.

2cy+ May. Whole wing pre-breeding, giving no clue to age. [CV03459]

2cy+ May. Whole tail pre-breeding, giving no clue to age. [CV04131]

2cy+ May. A bird showing a 'forgotten' P2. Theoretically, such a feather will give the age if it can be assinged to juvenile (very worn) or post-juvenile (worn) generation. In this case it may seem likely that P2 is juvenile (which means the bird is 2cy), but due to individual variation great care must be taken in the assessment. [CV04131]

2cy+ May. Same individual. [CV04131]

More Phylloscopus trochilus:
Ageing autumn

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