birds and grammar

Birds can grasp a grammar known as "recursive center-embedding," which means the ability for speakers to make new sentences by inserting words and clauses within other sentences.

If that wasn't interesting enough, there's a reference to Oedipus:

Thus, 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." This can theoretically go on without limit.