Bluebird House

I cleaned out the bird box this week to make room for this year’s broods of house sparrows.  They are prolific little buggers and they took over the bluebird house as soon as we put it up five years ago.  I would prefer actual bluebirds but there aren’t that many in this area so we make do with watching the sparrows.  However it looks like someone else is trying to make a move on the house.  The opening is being widened daily by someone with a very sharp beak.  Based on the birds in the area I’m guessing it will be the starlings but I haven’t seen them near it.