It takes one to know one, in this Moment of Science.   Yael: Don, what are you doing with all that candy?

Don: Oh great--now I'm going to have to find someplace else to hide my stash of goodies. You just can't trust anyone these days.

Y: Now if that isn't the pot calling the kettle black!

D: What are you implying?

Y: Well, did you know that in several laboratory experiments scrub jays, relatives of the blue jay, hid their extra food more cautiously when other jays were around? In fact, if another scrub jay was visible when the first jay buried its food, the first jay was more likely to dig up the food later and rebury it in another location.

D: So what does that have to do with my candy?

Y: Well, it shows that some birds are capable of more complicated behavior than we previously thought. Scrub jays are notorious for stealing food from each other so the fact that they behave more cautiously when other scrub jays are present might mean that they're able to speculate about the future behavior of their observers. Birds from species not known for thievery don't show the same reburying behavior.

D: Oh, so you're arguing something like, "It takes one to know one."Y: Exactly. In fact, when scientists allowed some scrub jays to dig up another jay's food after seeing where it was buried, the birds allowed to steal were more likely to rebury their own food later, when given the chance.

D: Hey, are you implying that the reason I hide my candy stash is because I steal other people's candy?

Y: Well, I am missing some peanut butter cups. And if the beak fits...