When you hear people laugh, you are more likely to laugh. This kind of thing has never been shown for a bird before, so let’s do some playback experiments with keas!
Schwing, R., X. J. Nelson, A. Wein, and S. Parsons. 2017. Positive emotional contagion in a New Zealand parrot Current Biology. DOI: 10.1016/j.cub.2017.02.020