The effects of human activity on the foraging behavior of sanderlings (Calidris alba)

• Main Author: Thomas, Kate
• Format: Text
• Language: unknown
• Published: Digital Commons @ CSUMB 2000
• Subjects: Swash; The Beaches; Calidris alba; Sanderling
• Online Access: https://digitalcommons.csumb.edu/caps_thes_restricted/144; https://digitalcommons.csumb.edu/cgi/viewcontent.cgi?article=1143&context=caps_thes_restricted

Urbanization and coastal development has dramatically reduced the beach habitat available for foraging shorebirds worldwide. Additionally, human recreational use of beaches has increased with the rise in coastal population density, which may pose a further threat to migratory and resident shorebird foraging. Here I tested the general hypothesis that recreational uses of shorebird foraging areas by people adversely effect the foraging behavior of Sanderlings (Calidris alba). Observations were conducted during January through May and September through December of 1999 on Moss Landing State Beach and Monterey State Beach (Seaside Unit) in Central California. Each focal Sanderling was observed for one minute while foraging within the swash zone. Observation data recorded included number, activity, and distance of people, day of the week, presence of dogs, and site. Observations showed the number, activity, and the proximity of people significantly reduced the amount of time Sanderlings spent foraging. Although the sample size was low, the most significant negative factor was the presence of free running dogs on the beach. Despite these differences, the experimentally determined minimal approach distance (14 m) did not vary significantly with the type of human activities tested (e.g. running versus walking, singly and in groups). Based on these results, policy recommendations for minimizing the impact of human beach activities on foraging shorebirds are: 1) for people to maintain a minimum distance of 15 meters from all birds, 2) to strictly enforce leash laws for dogs on beaches and 3) to restrict the area available for use of wind powered vehicles on the beaches.