When I got out of the car at the monument today I was immediately aware of some very vocal Coal Tits in the nearby trees.
There were at least three but there may have been a couple more, judging by the amount of noise they were making.
It may have been my imagination, but they sounded slightly different to the birds that I normally hear.
I concentrated on trying to get some pictures of the two nearest birds. What struck me was how blue-grey the upper-parts were and possibly the bib seemed slightly more extensive than on birds I regularly see locally.
I'm certainly not an expert on sub-species of Coal Tits and it seems a strange time of year for continental birds to turn up here. However looking at The Helm Identification Guide to Tits, Treecreepers and Nuthatches the birds seem to match both David Quinn's plate and Simon Harrop's description of Parus ater ater, the sub-species of Continental Europe and Asia, rather than our native Parus ater britannicus.