The effects of human approach on sanderling foraging behavior

• Main Authors: Hobdy, Anne, Rosch, Eric
• Format: Thesis
• Language: unknown
• Published: CCU Digital Commons 2019
• Subjects: sanderling; Calidris alba; foraging behavior; human impacts; shorebirds; animal behavior; Waties Island; Huntington Beach State Park; South Carolina beaches; Marine Biology; Huntington; The Beaches; Sanderling
• Online Access: https://digitalcommons.coastal.edu/honors-theses/338; https://digitalcommons.coastal.edu/cgi/viewcontent.cgi?article=1334&context=honors-theses

During low tide, sanderlings (Calidris alba) forage on small invertebrates in the sand of the intertidal zone. As a result, these common shorebirds frequently come into contact with humans who visit the beaches for a variety of activities, such as fishing or jogging. Here, the effects of three different approach types (undisturbed, passive, and aggressive) on sanderling foraging behavior were examined to help understand how human activities may be affecting their ability to search for food. At two local beaches, locomotory rate was recorded in addition to obvious changes in initial behavior. Treatments were defined as follows: 1) Undisturbed – sanderlings observed from a distance that does not influence their behavior 2) Passive - a human approached by walking at a steady walking pace from a predetermined distance 3) Aggressive - a more assertive approach at a noticeably faster speed from a closer distance. In general, sanderlings exposed to an aggressive approach moved at the highest rate, while the rates of birds approached passively or not at all did not differ significantly from each other. This was true for birds found at both locations. These results show a correlation between intensity of human approach and sanderling response, potentially impeding their ability to forage. The similarities between sites suggest that sanderling populations move frequently between local beaches and are therefore likely to show similar responses to the presence of humans regardless of beach location.