Brainier Birds Live On Islands

The study suggests the birds’ larger brains are the result of evolutionary processes that took place on islands rather than before colonization took place

Kea parrots, Nestor notabilis, endemic to the oceanic island of New Zealand, have a well-deserved reputation for being wickedly intelligent and, well, extremely mischievous. (Credit: Phillip Capper / CC BY 2.0)

If you’re an evolutionary biologist, there’s nothing on Earth that’s quite as special as an island. This is because islands are natural laboratories for studying evolution. Yet, at the same time, evolution on islands is, well ... peculiar -- predictably peculiar. For example, species that colonize islands show some very predictable evolutionary trends: vertebrates tend towards “medium body sizes” (this is the so-called “island rule”; ref), lizards converge towards equivalent eco-morphs (eco-morphs are species that occupy the same niche, have similar morphology and behavior, but are not necessarily close relatives; ref), and birds undergo a reduction or complete loss of flight capacity (ref).