As I returned a purchase in a shopping center on a particularly cold Sunday, an extraordinary thing occurred: A flock of pigeons came running up to me in the parking lot as if it were 1964, I were the Beatles and they were a gaggle of teenage girls. One “fan” even aggressively perched on my car roof.

For a moment I was reminded of Tippi Hedren in Alfred Hitchcock’s “The Birds,” but only for a moment. Extricating myself and securing the car, I returned the merchandise, wandering around the store a bit. Poor things, I thought of the birds. They were probably only looking for some crumbs. But with several eateries in the center, I was sure they wouldn’t go hungry.

When I returned to the parking lot, the birds were gathered around another car and driver, with a lot more of them perched on his roof. (Adulation is so fickle.) That’s when I realized in Sherlock Holmesian fashion that they were not looking just for food. They had figured out that each new car that arrived offered momentary warmth against a cold, mostly open space.

Nature is so smart. Human nature, not so much. Witness, ladies and gentlemen of the jury, Exhibit A — the Republican caucuses and primaries.