Noam Chomsky has endured many attempts to disprove his widely respected theories of language, but never have any of them come from a 3-ounce bird. The European starling, a tiny virtuoso, has the ability to learn and recognize a feature of grammar that has long been thought to be unique to human languages, researchers report in a new study.
Chomsky isn’t buying it, however.
A common characteristic of human grammar is inserting words and clauses within a sentence, without limit. For example, “Oedipus ruled Thebes” can become “Oedipus, who killed his father, ruled Thebes” or “Oedipus, who killed his father, whom he met on the road from Delphi, ruled Thebes,” ad infinitum. More simply stated, you can insert as many brackets as you want within a sentence as long as there are as many brackets on the right as there are on the left.
More here.