Effects of aircraft and recreation on colonial waterbird nesting behavior

Abstract

ABSTRACTBecause of the variability in the types of human activities to which animals are exposed and the associated responses by different species, there is a lack of consensus on the effects of humans on wildlife behavior. We studied the effects of military air traffic, all‐terrain vehicles, off‐road vehicles, and pedestrians on the nesting behaviors of least terns (Sternula antillarum), common terns (Sterna hirundo), gull‐billed terns (Gelochelidon nilotica), and black skimmers (Rynchops niger) at North Core Banks, Cape Lookout National Seashore (CALO), North Carolina. We deployed digital audio recorders and time‐lapse cameras within 9 colonies from May to August 2010–2011 and sampled nesting behaviors before, during, and after human activities. There was no evidence that military or civilian aircraft adversely affected incubation behavior for any of the focal species. The mean incubation rate by least terns was less during pedestrian events than control periods (91% vs. 79%, S = −2.2, P = 0.04). The current patterns of aircraft operations are unlikely to affect colonial waterbird demographics. Current beach management policies restricting human activity to >50 m from colony boundaries mitigated adverse impacts to nesting colonial waterbirds. © 2015 The Wildlife Society.