Pound for pound, bird brains are better! Their brains are packed more densely with neurons than others and more neurons equals more thinking power. They have more neurons than larger mammals such as apes and chimps.
I’m astonished that scientists actually counted the number of neurons. Neurons are tiny, they are 100 microns (1 tenth of a millimeter) long and there are millions of them in the smallest bird’s brain. Not only did scientists count them, the counted the number specifically in the parts of the brain responsible for intelligent behavior.
There are a few stand outs in their brains. The Goldcrest is, by far, the smartest bird per gram. Several of the smaller birds have higher ratios of neurons per gram. So they’re very smart for their size. But it’s the larger birds who win the show for potential genius since their brains are so much bigger. The blue and gold macaw shines above the rest in total neuron power. Budgies like Disco are in the top five for the number of neurons per gram.
You can read more in this article by The Guardian, Bird Brained and Proud: densely packed neurons give birds intellectual edge.