Figure 1. Plasma corticosterone (CORT) titers of house sparrows in response to a standardized stressor (30 min of restraint in a cloth bag) both before (Week 0) and after (Week 5) five weeks of exposure to four different diets: no oil, a low oil dose (0.01% oil weight:food weight), a medium oil dose (0.1% weight:weight) and a high oil dose (1% weight:weight) (n = 6 birds in each group).

The star represents a significant decrease in stress-induced CORT titers in the 1% oil dose birds at week 5 compared to controls. Values are presented as mean ± SEM.