Scary Bird Boxes.

Following on from my recent Blip colour is a recurring theme.
Are birds colour blind?
Would they choose a particular colour, given the choice?
Is it just us humans that have gone crackers?
Would any self respecting Blue Tit enter a pink bird box, there must be a university student out there itching to write a thesis on this very subject.

Any way I got an unexpected blip whilst Mrs. john39 dragged me kicking and screaming round a Department Store searching for two cushions of a certain pattern, hue, size and fluffiness. We didn't find any that were suitable.
I have just done a quick count, we already have ten, two which are likely candidates for re-covering. If the right material can be found.
Another blip perhaps?
Foot note, I just hope this is all kept secret!