Exposure to park visitors can disrupt animal behavior. Management strategies often aim to eliminate direct human disturbance; however, elevated visitor noise levels may remain. Coastal seabird colonies frequently overlap with scenic locations, resulting in high visitor noise and potentially altered behavior, habitat use, and fitness. We examine the impact of visitor noise on Brandt's cormorants Phalacrocorax penicillatus at Alcatraz Island, an important nesting site and one of California's most visited attractions. We used paired acoustic and video recorders to investigate the relationship between visitor noise levels and the behavior and relative abundance of cormorants in colonies adjacent to and far from a heavily visited building. Visitors were not visible from the cormorant colonies. At cormorant colonies adjacent to the visited building, disturbance-related behaviors increased with visitor noise. Conversely, there was no relationship between behavior and visitor noise in colonies far from the visited building. Cormorant disturbance behavior increased and abundance decreased when gulls were present at colonies adjacent to the visited building, whereas there was no relationship between gulls and behavior or abundance at colonies far from the visited building. Our results suggest that visitor noise alters cormorant behavior and decreases colony attendance, particularly in the presence of nest predating gulls. Visitor noise can be mitigated by implementing quiet zones, offering a cost-effective method of reducing disturbance to nesting cormorants. Understanding the relationship between altered behavior and demographic parameters is vital to conserving these coastal species and mitigating the effects from continued increases in recreation activity.