"At breeding colonies, herring gulls will sometimes peck to death another gull's chick should it blunder into their territory. And then they, or another gull, may eat is. I read all about this in 'Cannibalism in Herring Gulls,' an article by Jasper Parsons, who watched a lot of it go down on Scotland's Isle of May. I showed off my new vocabulary word: kronism, the eating of one's offspring. They also do that.... "While 20 to 30 percent of herring gull chicks that wander away from their nest are attacked, a similar number, one study showed, are adopted by a neighbor who feeds and protects them. As with humans, as with bears, a few individuals are responsible for the bulk of the species' churlish (to us) behavior. Of the 329 herring gull chicks cannibalized during the 1968 Isle of May breeding season, 167 were eaten by just four cannibals. According to Parsons, one out of 250 herring gull pairs practices cannibalism. It has nothing to do with food shortages, he found. It just seemed to be what they liked to eat best."

-- Fuzz: When Nature Breaks the Law, Mary Roach