Temperament traits and glucocorticoid metabolites in tropical screech owl (Megascops choliba)

Abstract

Animals constantly respond to stimuli from their surroundings, showing individual behavioral and endocrine differences upon perceived challenging and/or threatening stimuli. The temperament of 13 captive tropical screech owls (Megascops choliba) was defined by performing three challenge tests (novel space, taxidermist predator and trapping) to identify inter-individual differences and their possible relationship with the production of glucocorticoid metabolites (GCM). Feces samples of each bird were taken pre-and-post predator challenge to quantify GCM concentration by means of enzymatic immunoassay (EIA). The intensity of 13 adjectives selected to describe the owls' temperament was determined by three judges during behavioral testing. Only 3 adjectives (passive, vulnerable, and attentive) that showed strong inter-test and intra-individual correlation coefficients were considered. These adjectives were later grouped in a single dimension named “shyness”, enabling establishment of individual scores. The temperament of the owls showed correlation to post-predator challenge GCM levels (ρ = 0.79; p < 0.001). However, no significant differences were found in GCM levels before and after predator challenge. Our results both confirm that nocturnal behavior raptorial birds show positive relation between shy temper and adrenal response, and offer the non-invasive herein implemented methods for establishment of new hypotheses that will assess welfare of species kept under human care.