It was our second Belvide visit of the season on Saturday, and because of the small number of juvenile warblers we caught on the previous Wednesday, I almost called the visit off.
I'm really glad I didn't because although the catch was a relatively modest one of 48 birds, the balance towards juvenile warblers has shifted markedly, with 8 Chiffchaff, 7 Sedge warbler, 6 Reed warbler, 2 each of Blackcap and Whitethroat--and a single (adult) Willow warbler.
Perhaps the stand-out bird of the trip however, was an adult Tree Sparrow. Their numbers have fluctuated markedly over recent years --before this period they were rather common at the feeding stations with 50+ at a time not uncommon.
The head of this bird shows the key pointers of this being an adult. First the depth of colour of the head ( difficult to assess without a comparator) -- and the ear spot is black ( in juveniles it's grey)
The next pics show ageing criteria for two of our very common warblers.....
This is an adult Sedge Warbler as can be seen by the generally worn plumage and the thin almost white edges to some of the wing feathers--as opposed to:-
The wing of this juvenile Sedge is in immaculate condition with broad buff fringes to many of the feathers. Most juvenile Sedge warblers also have a 'necklace' of spots:-
Finally, one common feature of juveniles is that the feathers-especially under the tail and belly are lacking in strength and often look 'fluffy' for want of a better word
You can see how fluffy the feathers are on the underside of the juvenile Chiffchaff
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