We watched a male and female finch build this nest atop a pillar under our front porch a week or so ago. Once it was built, they disappeared. I thought they'd abandoned it. But SWMBO consulted her bird books and the Almighty Google and then said that they were "on their honeymoon." Apparently they leave for a couple of days to feed and mate.
And she was right. After about 48 hours the the female returned to the nest several times for a period of time, apparently laying her eggs. Now she's been perched on the nest continuously for most of a week.
I keep watching.