Saturday 24th September – Lytchett Bay   Leave a comment

After yesterdays large fall it was nice to ring a smaller number of birds at a more relaxing pace. The arable fields at Lytchett Bay delivered again with 57 birds, a mixture of Goldfinches, Chaffinches, Chiffchaffs plus a few Robins, Dunnocks, assorted tits etc.

Just Bob and I attended and with no trainees present we had the  time to examine the finches in detail. In particular ageing several of the Goldfinchs was problematic, with partially moulted tails, suspended moults and so on provoking discussion.

If you wonder why ageing of birds is so important to ringers, it is because much of the current BTO investigations are into population dynamics and for this can be undertaken accurate ageing of the bird population is essential.

 

Clearly a male Chaffinch, but ageing depends on assessing the shape of the outer tail feathers and the darkness of the tip of the central tail.

 

Juvenile (L) and adult (R) Goldfinch. As well as the obvious differences in head pattern the yellow in the wing is more saturated in the adult.

 

The same birds, the adult (above) seems to have suspended its moult as the outer four primaries are un-moulted. However there were some features of the tail that didn't fit in with this scenario!

 
Janis was returning from visiting the yacht in Gran Canaria at 1730 so I picked her up from Hurn Airport. A report of a remarkable 49 Black Terns at Ibsley Water, Blashford caused a detour on route, but by the time I arrived, all terns had gone and there were just thousands of roosting gulls.
 

Ibsley Water, Blashford

 
 

Posted September 25, 2011 by gryllosblog in Uncategorized

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