From my link
The idea that birds are unintelligent was initially proposed by looking at the brains of birds. Birds lack a cerebral cortex, which allowed scientists for decades to assume they were incapable of any higher thinking. However, researchers now know that a different part of the bird brain – the pallium – has evolved to do many of the same tasks as the cerebral cortex.
“Avian and mammalian brains seem to be functioning the same way, but interestingly their hardware is completely different,” said Emery, who noted that bird brains generally have shorter connections between specific parts of their brains than mammals.
“This structure means that birds might make decisions more rapidly then mammals, but we don’t know what implications this might have for their intelligence.”
But what is intelligence? It’s a question, really, for philosophy. Researchers rarely agree on an exact definition. But for his purposes, Emery described intelligence as “the ability to flexibly solve novel problems using cognition rather than merely instinct or learning.”
If I told you that day old chicks can count...would you think twice about eating chicken?
In other words, to Emery intelligence goes beyond rote learning to the ability to tackle a problem never before seen by an individual. This strict definition includes attributes usually connected to humans like plasticity and creativity. Still, Emery said that we need to start thinking of intelligence as species-specific and not compare apples to oranges or humans to crows.