Thursday, 22 March 2012

Greater Black-backed Gull ages

The three colour-ringed Greater Black Backed Gulls below were digiscoped on the River Adur opposite Shoreham Airport in the last couple of weeks - I find looking for and digiscoping local "CR" gulls strangely addictive, but I'm sure there are worse vices!  All were colour-ringed as chicks so their ages are known.  They make an interesting comparison.
49G  on the River Adur on 11 March 2012
48G on the River Adur on 17 March 2012
JH350 on the River Adur on 18 March 2012

JH350 is a second-winter (3CY), having been ringed as a chick on 09/07/10 at Grodholmen Lillehavn, Lindesnes, Vest-Agder, Norway.  It was seen on 01/07/11 at Heemskerk Strand, pole 47, Noord-Holland, The Netherlands and on 03/03/12 at Chouet Landfill Beach and landfill, Guernsey, Channel Islands.

As 48G and 49G are consecutively numbered it is no suprise to discover that they were ringed together from the same nest (on a building in Fécamp, Seine-Maritime, Normandie).  Looking at their bulk it is also no surprise that they are sister and brother.  They were hatched on 19/05/10 making them in their second-winter (3CY) too, so despite appearances all three birds are the same age.   JH350 is more faded than the French birds but might have been further south to winter under a brighter sun?

It is usually first and second-winter Greater Black-backed Gulls that I find can look similar.  49G particularly makes me realise that some second and third-winters are not straight-forward to age either. 

49G was hatched at Fécamp, Seine-Maritime, Normandie on 19/05/10, ringed there on 17/06/10 and seen on 22/09/10 at Le Havre, on 05/05/11 back at Fecamp and on  21/06/11 at Saint Aubin-sur-Mer (48G was also seen here on this date).

48G was hatched at Fécamp, Seine-Maritime, Normandie on 19/05/10, ringed there on 17/06/10 and seen on 23/05/11 at Veules-les-Roses, on 26/05/11 and 21/06/11 at Saint Aubin-sur-Mer, on 27/06/11 back at Veules-les-Roses and on 06/07/11 at Saint Aubin-sur-Mer again.  All French locations are in Seine-Maritime.

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