Groundbreaking studies show starlings can learn complex grammatical rules and sheep can choose the correct medicated food for what ails them. While linguists argue over the uniqueness of human language, European starlings at the University of California, San Diego, have demonstrated their ability to process complex grammatical forms by learning recursion, a pattern thought to be exclusive to humans. Take the simple sentence: "My dog is black." In recursion, humans are able to recognize that same sentence in more complex forms, such as, "My dog, who ran into the house, is black." A parallel situation was set up using songs composed of "warbles" and "rattles." The study, published in the April 27 issue of Nature, shows the birds were not simply memorizing complex sequences, but could distinguish between different patterns. Essentially, they were applying rules to solve the task. "The more closely we understand what non-human animals are capable of," said psychologist and starling study researcher Timothy Gentner, "the richer our world becomes."