This is from Lab Animal 44(7) 2015
Yawning is an involuntary reflex characterized by a gaping jaw, protracted inhalation and facial muscle contraction followed by a brief exhalation and jaw closure. Often considered an indicator of tiredness, stress, boredom or hunger, it occurs in most vertebrates. In humans and a few other mammalian species, yawning can also be elicited by observing the action in others. This “contagious yawning” might have a role in communication or behavioral coordination and is thought to represent a basic form of empathy.
In 2012, a team led by Andrew C Gallup (now at State University of New York at Oneonta) described observational evidence of contagious yawning in flocks of Melopsittacus undulates (budgerigars, or budgies). It was the first report of contagious yawning in a non-primate species in a natural context. Gallup’s laboratory has now followed up with an experimental study showing that a budgie will yawn in response to seeing another budgie yawn, whether the bird is in the next cage or on a video screen (Animal Cognition, doi:10.1007/s10071-015-0873-1; published online 27 May 2015). “Given the association between contagious yawning an empathy”, Gallup et al. wrote, “we propose that budgerigars represent a good model for exploring primitive forms of empathic processing.”