Thank you for posting this. It is a bit mistaken to say "neuroscientists haven't scrutinized their brains" when people like Harvey Karten (one of the authors on the paper at that link) have dedicated their lives to studying the avian brain. Not only do birds have something that looks analogous to neocortex, they also have a bit of actual cortex, and the rest of their brain (below the cortex) is very similar to ours as well. (Here's a review: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2507884/ )We study mainly mouse brains because that's where the genetics worked first, but hopefully new tools like Crispr will change that. By way of analogy, imagine you were an alien race trying to figure out how computers work: would you rather have infinite Windows boxes, or would you rather have some Windows, some Macs, and maybe a TRS-80 and a Commodore?
Birds have an analogous structure to the mammalian neocortex [1].
[1] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906560/