Crows are cool, but the fight against entropy could be made more omnipresent. Perhaps a street gets hit with a tree blight, and triggers a project to catch all the beetles, or make an ointment, to prevent large scale tree death and the spread to new streets. Maybe vandals deface the buildings, and we need to restore them.
I say this only because I have yet to run into a crow, and the only changes I see happen are when I forget to water my trees :)