birdbox problem

[hawthorns]

i made a bird box last autumn and this spring we had a pair of blue tits build a nest in it. recently we have seen no sign of the birds. ive looked in the box and found only half a nest and no eggs.i can only think they were spooked by our dog or something has happened to one of them and persume that they are not coming back and have abandoned the box . should i now remove whats left in the box or will other birds use the nest next time

[peanut]

Once you're sure that the nest has been abandoned you can remove the old nest as other birds will pull it out anyway.