Experimental evidence of contagious stretching and ingroup bias in budgerigars (Melopsittacus undulatus).

Previous observational research suggests that stretching is contagious in budgerigars (Melopsittacus undulatus). Here we report the first experimental evidence of this response through a reanalysis of a previous experiment testing for contagious yawning in this species. Using a repeated measures design, 16 birds were tested as pairs alongside familiar and unfamiliar conspecifics with and without visual barriers. Our results show that stretching behavior was temporally clustered only when the birds could see one another, corroborating previous observational findings supporting contagion. Additionally, for the first time, we show an ingroup bias in this response. That is, while the overall frequency of stretching did not significantly differ as a function of conspecific familiarity, contagious stretching was only present when cage mates were paired together. These findings are discussed in relation to recent research studying social cognition in this species. (PsycINFO Database Record

Experimental evidence of contagious yawning in budgerigars (Melopsittacus undulatus).

Experimental evidence of contagious yawning has only been documented in four mammalian species. Here, we report the results from two separate experimental studies designed to investigate the presence of contagious yawning in a social parrot, the budgerigar (Melopsittacus undulatus). In Study 1, birds were paired in adjacent cages with and without visual barriers, and the temporal association of yawning was assessed between visual conditions. In Study 2, the same birds were exposed to video stimuli of both conspecific yawns and control behavior, and yawning frequency was compared between conditions. Results from both studies demonstrate that yawning is contagious. To date, this is the first experimental evidence of contagious yawning in a non-mammalian species. We propose that future research could use budgerigars to explore questions related to basic forms of empathic processing.