Reed Warblers Prepare to Leave

Highlight of a catch of 64 Reed Warblers today was Y332103. Originally ringed as a juvenile on 25/08/2011. It was caught on  18th of June this year when it weighed 11.8 grams. Today it weighed 14.5 grams and had a fat score of 5 and was obviously preparing to  leave. The average weight of 5 other adults caught today was 11.1 grams.

Numbers of adults caught start to drop in late July and early August and most have left before the end of August.  We have 6 controls of adult Reed warblers on the south coast in the second half of July, 11 in August and 3 in the first few days of September. By contrast juveniles don't occur there until the middle of August and reach a peak in the last days of August and early September and continue into September. Almost  all the juvs caught today were in post juvenile body moult and had normal weights.

The other amazing thing about todays catch was the complete  absence of Sedge warblers on the same date last year at this site we  caught 8.
John