Sparrow Nest Crash UPDATE - What's A Bird To Do?

Amazing birds. Other than a very poor choice of nest location despite many options (or maybe they just want the highest penthouse?), this pair of sparrows diligently added to the last year's build only to have the whole double-decker come crashing down on the eve of egg-laying season.
Shrug. I saw no whining, no hand (er, wing-) wringing nor hesitation in taking care of business. If only we (I) had the same work ethic.