17 Nov 2014

Odd moults and poor quality feathers.

Ringing at Barry's always throws up something interesting due to the sheer number of birds we catch in his garden. Our most  recent session was Friday afternoon after a hastily rearranged meeting time due to torrential rain forecast first thing in the morning. It was a good session with 122 birds processed of which 90 were new and the rest re-traps. As usual the majority of birds were Blue & Great Tits but we had a good smattering of other species. Ringers in other parts of the country have been commenting on unusual moult in Blue Tits with birds having poor quality feathers and being infested with feather mites and lice. Whether this is as a result of poor weather during their moult  period or some other factor remains to be seen. I'm seeing this locally and sure enough we caught an adult Blue Tit at Barry's that had failed to moult its 4th & 9th primary even though it had replaced all the rest.

Some birds are moulting pretty late in the year and we caught this gorgeous adult male Bullfinch that was still growing its 6th secondary on each wing.

Bullfinches generally moult all their greater coverts during their post juvenile moult but retain the carpal covert. In juvenile birds this is edged  buff / brown whereas in adults it's white with possibly a hint of pink! This male was aged as an adult from the carpal covert which has a nice white fringe.
From memory I think this is the 8-9th Bullfinch we've trapped at this site in the last year and previously we hadn't caught any!

With autumn comes the annual raking of the leaves and with our lawn smothered I took the opportunity to spend some time tidying up whilst the weather was dry over the weekend. Of course it also gave me the opportunity to put some mist nets up in the garden.............

One of the 'highlights' was this unfortunate Great Tit that was 1st ringed as a juvenile in May this year. The feather quality is appalling and you can see the wear on the primaries already. How this bird will be able to fly if the wear gets worth I don't know. This bird is also very unusual in that it has retained the outermost juvenile greater covert. Great Tits very rarely do this although its quite often seen in Blue Tits.
This suggests the bird was under environmental 'stress' during both its fledging period and its post juvenile moult. Assuming the bird was hatched during April we had some pretty torrential rain that would have made the adults job of feeding the youngsters very hard. It looks as if there were fault bars in all the primaries and the feathers have broken / warn at this week point. The bird was otherwise healthy with a good fat score and weight. It'll be interesting to retrap it again over the winter to see how its fairing.

On a brighter note I retrapped a Goldfinch 1st ringed back in July as a recent fledgling. It has undergone a post juvenile moult and was sexed as a male. It's retained a fairly obvious juvenile greater covert. Its also obvious from this photo how the white bit of the feathers wear faster than the darker bits! This is a feature of white feathers  and can also be seen on the tail of Goldfinches.

Goldcrests have been a feature in my garden this year. Although not huge numbers there has been a significant increase in birds compared to previous years and I ringed another new bird this weekend as well as retrapping two individuals from previous weeks.

2011 - none, 2012 - 1, 20013 - none, 2014 - 4!

The nearest they breed to me is Stanney Woods about 3 km away as the bird flies so whether these are local birds or some of the huge number of Scandinavian migrants filtering across from the east coast remains to be seen.

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