The startle responses of blue jays to Catocala (Lepidoptera: Noctuidae) prey models

Abstract Artificial moth models were presented to caged blue jays, Cyanocitta cristata , in order to investigate the effectiveness of deimatic displays in underwing ( Catocala : Noctuidae) moths. The models had flexible, patterned ‘hindwings’ which were concealed behind cardboard ‘forewings’ until the birds removed them from a presentation board. Jays which had been trained on models with grey hindwings exhibited a startle response when they were exposed to Catocala -patterned hindwings. In contrast to this, subjects trained on Catocala models did not startle to a novel grey hindwing. The startle response to Catocala patterns lasted over several days until birds habituated to the models. When the jays had habituated to one Catocala hindwing pattern, a novel Catocala pattern always elicited a startle response. Familiar Catocala hindwing patterns which appeared in an anomalous context (i.e., associated with a different forewing pattern) also evoked a startle response from these birds. Novelty, oddity, conspicuousness, and anomaly are considered as possible stimulus characteristics which trigger the startle response.