Sunday 12 June was the observatory’s fifth CES ringing session. Now we are approaching mid-June we are starting to catch fledglings like these cute lesser whitethroats (sylvia curruca), mother was caught too!

Two lesser whitethroat fledglings

Ageing this common whitethroat (sylvia communis) proved tricky. Whilst its primaries, secondaries and tail feathers looked adult, and no clear moult break in its greater coverts could be detected the small and medium alula feathers look juvenile. On the face of it one might lean towards an age code of 6 (adult) but the two alula feathers caution against this. Regardless, it does raise the question of aberrant moult strategies since juveniles in their African wintering grounds are only thought to undertake a partial moult of body feathers and wing coverts.

Common whitethroat wing