Human presence is positively related to the number of bird calls and songs: Assessment in a national park

Human disturbance has been shown to provoke physiological and behavioral responses in birds, so nature-based tourism might reduce bird abundance and diversity. The negative consequences of human disturbance might be expected to be maximized during eventual massive events in highly protected areas such as national parks. In this study, the consequences for soundscapes of human presence and disturbance of thousands of visitors during an ornithological fair (massive event) on the bird community of the Monfragüe National Park (Spain) were analyzed. We found that the number and diversity of bird vocalizations did not decrease during the massive event. In contrast, the presence of people in the Monfragüe National Park was associated with an increase in the number and diversity of vocalizations. The effect of human presence on the number of calls and songs differed: the number of calls mainly increased during the massive event when people were present, while the number of songs increased when people were present, particularly during the measurement campaign without the massive event. The human shield hypothesis, along with other behavioral and environmental factors, might potentially explain the results obtained.