Today I witnessed the reason for all of that hard work closing the hole.
I have to say, this is the first time the jackdaws have visited our back garden. They are quite frequently out on the big front lawn (which actually belongs to the 'big house'; we are a gate lodge) but I've certainly never seen them venture into the back. I guess they've found something interesting enough to tempt them in!
I'm in a bit of a dilemma over this. As far as I know, the nuthatches haven't yet laid their eggs; they were still bringing in leaves and mud yesterday so I'm only assuming this is the case. Once they do, however, I'm sure the jackdaws will be back to stick their beaks in and cause trouble and I really hate the thought that they might actually cause harm to the birds or their eggs. I know it's nature and you shouldn't interfere but it's pretty damn hard when you've watched these birds work hard to build a safe place to nest. I'll be keeping a very sharp eye on the situation.
Photos snapped this morning after refilling the tray with black sunflowers.
In other news, I have seen the blue tits go into the nestbox several times carrying bits of twig and straw in their beaks, so I think I can venture to say that they have started nesting in there-hooray! It's still no guarantee they will actually lay eggs but the signs are all positive so watch this space!