>>13269304It's not just incubation, it's feeding and protecting from predators too. You ever seen a mother bird? Literally ALL they do is fly back and forth, back and forth, from foraging, to the nest, dozens, hundreds, THOUSANDS of times in the span of weeks. Not to mention it's dangerous. Snakes, rodents, cats, and raptors are all looking to make a meal out of weary birds.
Why go through all that trouble when you can have someone else do it for you?
