Only when trained to do so. Which is conditioning. They aren't passing because of an innate 'intelligence'. Any pigeon that isn't trained to do it can't do it.
This is a form of intelligence. An animals ability to associate, or be able to deduce a particular action (which it normally wouldn't associate with food from an evolutionary standpoint) with a food reward is without doubt a sign of intelligence.
In rats. Not pigeons.
In the late 1940's, a famous biologist called Skinner conducted an experiment with pigeons which highlighted how hungry pigeons could develop a superstitious behaviour if it associated the behaviour in question with a food reward. The superstitious behaviour varied from pigeon to pigeon, and included head tossing and turning in a counter clock-wise manner which resulted in a food reward. Such behaviours require a basic thought process; the reward of food is each time associated with the original behaviour. The fact these superstitious behaviours can develop in pigeons within a laboratory setting highlights how they must possess an above normal level of intelligence (Edit: obviously in relation to similar species with similar brain anatomy). Which species is the most superstitious on the planet...? Coincidence? I think not.
Yeah, that's the Skinner Box. It was used to show how animals responded to operant
conditioning. It was always rewarded with food. Again, the animal doesn't have to know
why it's doing it (intelligence), just that doing it rewards it with food
after it's been done a number of times (conditioning).