So when I was leaving to go mountaineering on Friday, the three new finches were standing up and flexing their wings but still staying in the nest. By Saturday night they were gone. I went out to clean the nest off the ledge today and noticed that there was now a new nest nearly complete at the other end of the carport. They're efficient, those finches. Anyway, I've repositioned the NestCam to look at the new nest. Nothing in it yet. :)
When I pulled down the old nest, I fould the first egg--the one that seemed to disappear in two consecutive inspection images (1) (2). Apparently they just buried it and went about their business. It's sorta greyish now and much smaller. Should I crack it open?
I especially like the fact that in the photographs after the eggs hatch, you can see the rim of crusty birdshit growing thicker and thicker. Can you make a time-lapse video -- say, 1 hour per second? -- of the nest over that time period? Watching the cruft build up would be kinda cool, albeit gross.
EAT BIRD!
I don't think it's normal for an old (but neglected or infertile) egg to shrink. I wonder if the mother is being limited by her calcium supplies.
Some birders put out baked egg shells and claim to attract a lot of birds to feed on them in spring.
Chickens love to devour their own (empty) egg shells, and their production benefits from it.