Aww so sweet. The moms look quite similar. I wonder if they're sisters?
You could try moving your nesting box so the entrance is right next to the cardboard house. Is the nesting box covered? They probably feel the smaller house is safe.
I wouldn't worry too much though. They'll move if and when they feel it's necessary.
You could try moving your nesting box so the entrance is right next to the cardboard house. Is the nesting box covered? They probably feel the smaller house is safe.
I wouldn't worry too much though. They'll move if and when they feel it's necessary.