thanks Bernd Heinrich

Fifteen feet over the porch a plucky sparrow VERY handily seeing off a raven--who had probably tried to snack on a nestling--harassing its tail so thoroughly it couldn't get a good take off motion going, hence a series of short stalls which then caused it to drop for split seconds onto the sparrow's relentless ass-poking beak. But the sparrow grasped an important truth about ravens--they're not so tough, their aggression and rapaciousness held in check by enormous caution, especially about the unfamilar. They can be surprised--the sparrow must have rushed the raven in a split second--and lulled into a false sense of security, which must be when the eagles get them.