PC, is it typical for the parents to go save themselves during a storm and not try to protect their chicks? These chicks were pretty big already so hovering over them likely wasn't possible.
Oldest chick was 18 days old which means these two were about the body size of their male parent sans the feathers - we band them just at 21 days old because their feet have finished growing, so these two were teenagers. Don't know how much protection the parents might have been able to provide - and any storm that is strong enough to get 2 almost banding age chicks out of the nestbox that is pretty sheltered and secure is a heck of a storm - and it was (
Storms cause damage throughout Nebraska (photos & video)) including at least one tornado (
Storms batter state with hail, high winds and heavy rain .
As for "saving themselves", yes that is normal evolutionary behaviour - if offspring dies but the adult survives there can be more offspring, if the offspring survives but the adult dies, the offspring usually dies too. But to be fair to Alley & 19K it likely had nothing to do with saving themselves, they could very well have been in the box with the kids and the only thing that saved them was their ability to fly though flying in that kind of weather likely not a evolutionarily smart thing to do. We may never know, it may have been a fluke gust of wind, chicks crowding into the wrong corner of the nestbox, chicks trying to find a more sheltered spot and remember, this is the boot-scoot period of development, they can't walk, they are just starting the waddle-stomp phase. Unless someone was able to watch on-camera and reports, it's possible we will never know what happened, just that the two chicks were lost.