While digesting one of the many rounds of holiday feasts and leftovers, with plates of cookies in between, a headline caught my eye: "Big brains or big guts: Choose one." As much as the post-holiday-dinner-brain-fog is real, I don't love the implications of those options. Luckily, the article wasn't about humans. It was examining birds in cold, highly variable habitats, and their struggle to survive. Essentially, birds have two options: spend energy maintaining a big brain that allows them to find high-quality food, or spend energy maintaining a large stomach that can make low-quality food sufficient in high quantities. According to the research, if you are a bird who needs to survive cold winters, you must choose one. There's no middle ground.