The development of stereotypic behavior in caged European starlings, Sturnus vulgaris.

Stereotypic behavior in captive animals has been hypothesized to emerge from thwarted natural behavior patterns and is thought to be more common in captive-reared animals. However, data on the early stages of developing stereotypies are currently scarce. We compared the development of stereotypic route-tracing and somersaulting in hand-reared and wild-caught starlings placed in individual cages for the first time. We found that wild-caught birds were less active but showed more escape motivation and more evidence of route-tracing behavior. Furthermore, somersaulting was only observed in wild-caught birds. Development of somersaulting was predicted by subtle differences in behavior during the first few days in cages and developed in individuals with low levels of route-tracing behavior. Our data suggest a role for escape motivation in the development of starling stereotypies and additionally that route-tracing and somersaulting may represent alternative outlets for thwarted escape. In contrast to observations from mammals, our results show that stereotypies are more common in wild-caught starlings.