Nest box

I have a large blue tit nest box in my garden that is used annually two or three broods per year, this box as a divider in the centre and I have noticed on cleaning and painting in the winter that they only ever use one side of the box and never two families in the box ?  Kind regards Rob 

  • Probably a territorial thing Rob, too close to one another to have more than one family. As to only using one side, could be something environmental, is one side in more sunlight therefore warmer through the day? Is it easier access from any perch they may use before entering? Perhaps they don't like the colour lol. Pure speculation on my part though