This little bird has been around for a few days. I can't identify birds without a photo - once I look at pictures in a bird book, I can't remember what colour head/body/whatever the one I'm trying to identify had. 

Now that I have photos, I'm fairly sure that this is either a female or juvenile male blackcap.  The sparrows try to chase it away from the food, but it's quite persistent.  It's bitterly cold at the moment, so I've been giving them extra rations.