Birds

I work on the 16th floor of the Phillip Burton Federal Building, just north of Civic Center. As I've sat here diligently working away, I've noticed more than a score of seagulls fly, one at a time and at irregular intervals, northwest, thereby gaining a lot of altitude in exchange for little actual work.

I've also noticed a pair of hawks or eagles that seem to enjoy resting on top of City Hall.

That there is not constant carnage resulting from this ecological combination demonstrates to me that seagulls are nasty critters.

Your conclusions may vary.