Locustella naevia - autumn

Common Grasshopper Warbler

AGE – BEST CRITERIA:


In 1cy, whole plumage is fresh and uniform, including wing and tail. Adult shows worn wing and tail (but note that some may include single or several RR in the post-breeding moult), and some adults shows moult contrasts in GC, TT or RR. Tongue spots are said to be inreliable as they may quickly disappear during first autumn, and some adult may retain them. 

1cy: 
  • Whole wing is fresh and uniform. Signs of wear starts to show in tips of PP during mid or late autumn.
  • Tail is fresh and uniform.
2cy+:
  • Whole wing is worn, often notably so in tips of PP and PC.
  • Whole tail is worn.
  • Many birds have included some (or all) GC, TT and RR in the post-breeding moult, which then contrast clearly to worn pre-breeding feathers.

1cy October. Whole wing uniform and fresh. [CS00088]

2cy+ September. Wing is typically worn (note esp. the freyed and bleached tips to PP). This individual has conducted a rather extensive partial post-breeding moult, including GC1-9 and some TT. [CP47768]

1cy September. Fresh and uniform juvenile GC. [CP39925]

2cy+ September. Adults often show a uniformly worn pre-breeding wing, but birds with a more extensive post-breeding moult (like this one, with 4 central GC freshly moulted) are not uncommon. [CP40283]

1cy October. Juvenile PC are fresh with dark centres and olive edges. [CS00088]

2cy+ September. Adult PC are worn with faded brown centres and freyed olive-buffish edges. Note also the worn AL. [CP40283]

1cy October. Juvenile TT are fresh with dark centres and olive edges. [CS00088]

2cy+ September. The two longest TT are post-breeding, contrasting to the shortest T, the SS and innermost GC which are all from the pre-breeding moult. Adult birds may include 0-3 TT in the post-breeding moult. [CP47768]

1cy September. Whole tail is uniform and fresh. [CP47831]

1cy October, showing variation in tail pattern. [CS00088]

2cy+ September. Adult showing typical wear in the pre-breeding tail. Note that the right R6 (partly covered by the broken R5) is fresh post-breeding. [CP47768]

2cy+ September, showing completly moulted post-breeding tail, apart from R4-5 i left half, which were recently shed. Single moulted RR are often seen in adult (like in the bird to the left), but a more advanced post-breeding moult, like in this bird, is not common. [CP40283]

1cy September. Typically juvenile iris being cold olive-grey. [CS04376]

2cy+ September. Adult iris is slightly warmer greyish-brown (although there is usually no need to examine iris during autumn in this easily aged species). [CP40283]

More Locustella naevia:

Ageing spring
Moult

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