Bearded Tits and Grit-The Season to Date

Its been a rather frustrating season to date compared with the previous nine years of our study of gritting behavior. This weekend was typical, 15 birds (all colour ringed) on the trays on Saturday,  so full of hope I canceled plans to ring and spent Sunday morning watching empty grit trays on what appeared to be a really suitable morning-calm and cold. Frustrating to say the least.

However a  quick look at the sightings to date produced some interesting findings. In total to date we have recorded 176 sightings of colour ringed birds. This compares with 290 for the same period last year. But there are more young birds this year (45 compared with 17 in 2012). However we have recorded 25 different adults and 28 birds of the year visiting the trays this year, compared with 29 adults and 11 young birds in 2012. Effort have been very similar,  so we have recorded more individual birds this year but they are obviously visiting the trays less often. In 2012 one bird visited on 22 days. This year  the largest numbers of days by an individual  was just 10. I suggested in a recent posting that the mild weather and low water levels may be the reason for the  lower use of the trays

Overall though survival this year to date has been good. We ringed  21 nestlings and 16 of these survived to at least 2 months. Of the 45 juveniles ringed, 38  at least survived to early August and 32 of these have been recorded post moult.

Survival over last winter has also been good for  of the 17 birds ringed as juveniles in 2012 no fewer that 13 have been recorded  this year, a crude survival rate of 78%.

John