Looked it up on "NestWatch" site, it said under brooding "Songbirds and most seabirds have altricial young, meaning that the newly hatched birds are blind, featherless, and helpless. Immediately after hatching, altricial birds can do little more than open their mouths to beg for food. They remain in the nest where the parents can feed and protect them while they continue to develop. For the first week of life, most altricial birds cannot control their own body temperature and must be constantly brooded (kept warm) by their parents."
There was big drama around the nest today. Another house finch couple nested in the same spot about 6 weeks ago, and lost their hatchlings when a bluejay (scrubjay) ate them. The first pair spotted the new nest today, and tried to build their own nest next to this nest--BADLY disrupting the feeding by these parents--it was a constant chasing off by both pairs. I have had house finches nest in this spot for decades, and have never seen the nest unattended when they are nestlings of this age.
NestWatch shows the incubation period as 13-14 days, and an additional 12-19 days brooding time. They've been brooded only 3-4 days, far short of the 12-19 days--so I am worried. I'm cold in the house now, and they are a few ounces of featherless skin, outside. I didn't find that NestWatch site until you said "brooding" so I googled that word. I spent 2 hours googling before finding this site, and got no info about brooding times in all my searches.
I hope you're right fugl--thanks for the post. BNA says 3-8 days, other site says 12-19 days, I wonder why such a big discrepancy? I want to go place some fluffy something on the nestlings to keep them warm--but I'll try to let nature take its course.