Heart rate (HR) reactivity to, and recovery from, 3 different types of human stressors (sound, 10-m approach, and capture-immobilization) for king penguins brooding in areas of high (HD) or low (LD) human disturbance. (A) HR reactivity (in bpm/sec) is the speed of HR increase to its maximum during the stress. (B) HR recovery (in bmp/sec) is the speed of HR decrease back to resting levels following reaching of HRmax. Results are given as means ± SE. Statistics are figured for *p < 0.05, n.sNon-significant.