text:  I haven't looked at it in two weeks, and I don't really want to. How big could that have grown? Should I just leave it alone and wait until wintertime, or are they going to bother my birds when they get bigger? What's going to happen? It's possible they could bother the birds. It could bother you, too, if you're going to refill the bird feeder. This time of year, they can double in size within a week, the nest. So in two weeks, I mean, you're talking golf balls, so we're probably about the size of a softball by now, if not bigger.