How Can Small Birds be so Smart?

Interesting finding that explains how small-brained birds like crows and parrots can be so intelligent:

The study, published online today in the Proceedings of the National Academy of Sciences, found that 28 bird species have more neurons in their pallial telencephalons, the brain region responsible for higher level learning, than mammals with similar-sized brains. Parrots and songbirds in particular packed in the neurons, with parrots ranging from 227 million to 3.14 billion, and songbirds—including the notoriously intelligent crow—from 136 million to 2.17 billion. That’s about twice as many neurons as primates with brains of the same mass and four times as many as rodent brains of the same mass. . . . One surprising finding was that the neurons were much smaller than expected, with shorter and more compact connections between cells.

Instead of getting bigger, their brains got more densely packed, which saves weight and allows their neurons to be shorter, which saves more weight. Fascinating, what evolution can do.