Reed Warbler End of Term Report

Have at last got round to working out the results of  our Reed Warbler Study for this year at Leighton Moss RSPB Reserve. This is run as a spin off to our main study of Bearded Tits. During the four months June to September we made 59 visits to our five sites spread  throughout the reed bed, around our normal number of visits over the past five years.

The adults were late in arriving this year and the population certainly appears to have been down on recent years. This year we caught 146 adults (88 new birds and 58 retraps from previous years). This compares to an average of 192 for the previous five years. The late arrival and an early departure may well have reduced the catch but even so the breeding  population does appear to have been lower.

However the excellent late spring and summer weather appears to have been good  for productivity for despite the apparent drop in the breeding population we ringed 743 young birds, well up on the 504 in the poor weather of 2012 and also up  on the five year average of 598.

Departure of adults was certainly earlier than usual, many apparently leaving in late July/ early  August. We only caught 15 adults in August compared to  an average of 70 over the past few years. I wonder if the late spring arrival  meant that  very few birds attempted a second brood. Also the good productivity suggested fewer re-lays after a failed attempt.

Sedge Warblers also appear to have  had excellent productivity with a catch of 326 compared with an average of 270 over the past five years.

John