Less activity means improved welfare? How pair housing influences pinyon jay (Gymnorhinus cyanocephalus) behavior

The activity level and specific behaviors exhibited by captive animals are crucial indicators of their health and welfare. Stereotypies, or repetitive behaviors that have no apparent function or goal, are performed by animals experiencing poor conditions in their environment and indicate welfare concerns. Changes in the housing environment in particular may have critical influences on behavior and welfare. Here, we measured behavioral changes in a captive pinyon jay (Gymnorhinus cyanocephalus) population (n = 12) associated with a shift from single to pair housing. Using automated video processing, we show that pair housing greatly reduced overall activity levels in these birds. The stark reduction in activity was surprising, as we expected that social housing would increase interactions between birds, thus increasing activity levels. Upon further analysis, however, we found that stereotypic behaviors like beak scraping, jumping, pecking, and route tracing decreased after pair housing, whereas a calming behavior--preening-- increased. Our results indicate that pair housing may reduce overall activity in pinyon jays; however, this reduction is primarily in stereotypic behaviors.