Responses of Imperiled Snowy Plovers (Charadrius nivosus) to Anthropogenic and Natural Disturbance in the Florida Panhandle

Abstract. The habitat of beach-nesting birds often overlaps with areas heavily used for human recreation. Human activity has been linked to negative behavioral and reproductive consequences for shorebirds; therefore, it is important for managers to understand how to best mitigate disturbance. In Florida, there is concern that human disturbance negatively affects the state-threatened population of Snowy Plovers (Charadrius nivosus). We measured response probabilities and flight initiation distances (FIDs) of Snowy Plovers at sites experiencing a range of human use. Snowy Plovers responded at longer distances to pedestrians and dogs than to competitor and predator species, except for incubating birds which responded at longer distances to predators. At all distances below 50 m, plovers had a response probability of > 0.2 for pedestrians. Dogs induced such strong reactions at close distances that plovers always displaced before they came within 20 m. Brood-rearing plovers were more sensitive to anthropogenic disturbance than plovers engaged in other behaviors. Plovers at sites with high disturbance generally had lower FIDs than birds at sites with less disturbance. Our findings illustrate the importance of accounting for differences in disturbance regimes among sites when setting buffer distances, and for protecting brood-rearing areas in addition to nesting habitat. Due to the severity of responses prompted by dogs, managers should strongly consider dog prohibitions at sites with breeding Snowy Plovers, as reasonable buffers may not be adequate.