HUMAN DISTURBANCE OF SNOWY PLOVERS (Charadrius nivosus) IN NORTHWEST FLORIDA DURING THE BREEDING SEASON

Snowy Plovers (Charadrius nivosus), a state-threatened shorebird in Florida, are subject to human-caused disturbance due to the proximity of their habitat to development and recreation. The degree to which human disturbance is a limiting factor for reproduction is unknown, and even basic data on disturbance rates and be- havioral responses are lacking. Fencing often protects nesting areas from disturbance, but foraging and brood-rearing areas are typically unprotected. We measured rates of disturbance in plover habitat and response distances in Northwest Florida in 2010, us- ing focal observations and track counts for unprotected foraging sites and brood-rearing sites as well as protected nest sites. Our results suggested that a 40-m buffer could pre- vent flushing of foraging adults by pedestrians, while a 50-m buffer could prevent alert- ness responses by incubating adults to pedestrians and vehicles. Foraging adults were more sensitive to humans than to potential competitors and predators, and chicks did not respond to potential disturbances except for in one observation where a pedestrian approached within 10 m. Current 50-m buffers appear adequate to prevent incubating birds from being flushed by humans in our study area. Consequences of disturbance to foraging adults require further evaluation. Chicks may be susceptible to mortality due to vehicles because they did not exhibit disturbance responses to vehicles as close as 10 m.