Responses of incubating hooded plovers (Thinornis rubricollis) to disturbance

Hooded Plovers (Thinornis rubricollis) and recreationists co-occur on the ocean beaches of southern Australia, and it has been suggested that disturbance of the breeding birds by humans constitutes a conservation problem. This study examines whether humans disturb incubating Hooded Plovers and places that disturbance in context with naturally occurring disturbances. Incubating Hooded Plovers encountered and responded to a variety of human and natural stimuli. The most common response involved leaving the nest for a period of time (an "absence"), and humans were responsible for 33.1% of time spent off nests. The response rates of incubating birds varied with the type of stimulus, with higher than expected response rates to two species of potentially predatory birds. About 17% of encounters with potential causes of disturbance occurred while birds were already responding to other disturbance, and this prolonged the return to the nest. Absences from the nest that were not apparently caused by disturbance were shorter and less frequent than those caused by external disturbance stimuli. Nest habitat influenced the response to encounters with humans, and on average foredune nests suffered the greatest decrease in attendance per encounter. This study has confirmed that human disturbance is more frequent than natural disturbances, and that humans decrease nest attendance substantially and more than any other source of disturbance.