A busy weekend with conditions good for mist netting at Leighton Moss RSPB Reserve. One highlight was the catching of two Reed Warblers. Numbers drop off steeply by October but these late birds are obviously getting ready to migrate. One weighed 15.2 grams almost half as much again as they weigh in summer and it's breast was completely covered in fat. The second bird weighed in at 13.8. I thought the first bird was the heaviest Reed Warbler we have ever caught but a quick search with the aid of IPMR brouught up one at 17.2 grams on October 6th 2005. The majority of the 105 birds ringed in previous Octobers were putting on weight but a few were as low as 9.9 grams.
Our main study species is Bearded Tit and with a catch of 17 birds and grit tray sightings of colour ringed birds we logged up a total of 33 different birds. Most satisfying was the catching of three previously un-ringed birds, from the pale iris colour we could age them as birds of the year- this brings our total of young birds for this year to 42, well up on last years poor show of just 17. Of the 33, 19 were this years birds and 14 were adults. This reflects the finding that adult birds start to visit the grit trays a week to 10 days before the bulk of the juveniles.
Earlier in the autumn I reported on the low numbers of Blue Tits we were catching and surmised that they were still in the woodlands where there was plenty of natural food. Numbers have really started in pick up now in the scrub and reed bed and this was reflected in our catch this weekend.