Cold Winters Theory applies to birds:
Last week during skiing holidays I saw a popular scientific program on animal intelligence in the evening, and they presented something like the Lynn-Miller-Rushton cold winter theory! Birds (chickadees) living in Alaska have bigger brains and are more intelligent than birds living in Kansas! This is an independent very valuable support for the cold winter theory on intelligence.
Links to the relevant papers in Emil Kirkegaard’s post.
In general, therefore, it seems best to focus on animals that tackle the cold winter problem head-on instead of avoiding it somehow (migrate, hibernate, or single-year lifespans). Among birds, the smartest birds are of the Corvidae family — in particular crows, ravens and magpies — and they generally don’t migrate in the winter. Of the non-Corvidae, I think the smartest birds are some of the parrot species. These also often don’t migrate.
As Lazy Glossophiliac points out, yet another bullseye for folk stereotypes: “Fascinating that Corvidae would be the smartest birds because stereotypically it’s ravens. Well, and owls.”
Someone should do a meta-study of IQ or r/K-selection differences across the animal kingdom for suitable species – span many latitudes; don’t sidestep the cold winters problem; haven’t been artificially selected by humans – to ascertain whether CWT really is universal.
Step one: “Does someone know a good way to get habitat location information for a large number of species automatically? Preferably numeric information.“