One thing intelligence seems to require is a lot of energy to drive it. You have to get that energy from somewhere. Humans probably get it by cooking food. N

One thing intelligence seems to require is a lot of energy to drive it. You have to get that energy from somewhere. Humans probably get it by cooking food. Normally animals have to use a lot of energy to break down the food, humans solved that by using an external energy source to break it down before eating it. Birds need a lot of energy for flying. They don't cook. They solved the energy problem by developing the most efficient mitochondria on the planet. They pay a fairly high price for that in terms of infant mortality, but I guess the ability to fly is worth it. It means when they aren't flying, they have a lot of excess energy to power an highly intelligent brain. They could then use that brain to detect when their mate was screwing around, and decide if it was worth ditching them. That's all guess work of course. I'm no expert, just belly button gazing really.