Do they use nest boxes or trees meant to ask lol
Hi Debs. It's great that you get Coal Tits outside your window, they're such beautiful little birds. Coal Tits will use nest boxes but if the entry hole is too large they can often be chased off by larger birds such as Great Tits. I think around 25mm is a good size for the entry hole and this may also attract Blue Tits as well. There is some information from the RSPB about nestboxes if you look HERE. There is also some other good information about Coal Tit nesting habits in more natural surroundings if you click on the part that says 'Behaviour and Ecology' on the page that you'll find HERE. Hope this helps you Debs.