Rooster box next to nesting box?

Hi everyone! 

Im looking for some advice please. I put up a rooster box on the wall in my garden last Autumn. I already have a nesting box on the same wall which every year I am lucky to have blue tits nesting in. 2 blue tits have recently been visiting the garden but seem to spend most of their visits going in & out the rooster box, not the nesting box? Im anxious that the rooster box may avoid them nesting in the normal bird box this year? Or that the blue tits may be viewing the rooster box with the intention of nesting in it? Even though hole is at bottom of rooster box? 

Any advice much appreciated!

Thank you

• Wendy