I think her? his? partner has taken a powder & the one that's left is falling down on the job. My neighbor said there were 2 eggs previously. WHAT HAPPENED TO THE OTHER EGG? This one has been taking off more, or possibly my schedule has been such that I've seen him? her? absence. I can tell the 2 apart (but not which is which by gender) & I'm (pretty) only one has been around. I thought they incubated by instinct. Oh gosh, I hope nothing has Happened & she? he? is about to be a single parent. You can't really tell what's going on inside the egg, but I think there's another week before it hatches. How long can a bird leave the nest & still be incubating successfully? Up to 10 hours! OK, one worry allayed.