Blue tits

Hi there,

I’m quite new to the birdy world, and new to this group. I came across it when I was trying to find out why the blue tit that visits to feed from my flats window bird box has scruffy, scarce feathers. I’ve noticed especially on its head, could this be a disease or a time of year thing? It doesn’t look good at all, any help would be appreciated. I’ll try and get a pic next time he visits!

TIA,

Emma