Bird brains have higher neuron density esp in the forebrain, but I’m unsure if this also translates into higher synaptic density or just less synapses per neuron. Regardless it does look like bird brains are optimized more heavily for compactness, but its not clear what tradeoffs may being made there. But heat transport cooling scales with the surface area whereas compute and thus heat production scales with volume, so brains tend to become less dense as they grow larger absent more heroic cooling efforts.
Bird brains have higher neuron density esp in the forebrain, but I’m unsure if this also translates into higher synaptic density or just less synapses per neuron. Regardless it does look like bird brains are optimized more heavily for compactness, but its not clear what tradeoffs may being made there. But heat transport cooling scales with the surface area whereas compute and thus heat production scales with volume, so brains tend to become less dense as they grow larger absent more heroic cooling efforts.