Chaffinch

I've had a gentle day starting with breakfast and a good book in bed, then a bit of cleaning in preparation for Becky's arrival on Thursday, very much looking forward to that.  I haven't been far from the house till Hobbler time so I turned to the elder tree for a blip.  It wasn't till I looked at this chaffinch in large on the computer that I spotted what looks like a fungal infection on its leg?

Postscript:  The BTO website says this is caused by mites and they 'are dry encrustations made up of material produced by the bird in response to the irritation caused by the mites.'