Due to variability in aircraft overflight type and associated animal responses, there is a lack of consensus on the effects of overflights on wildlife populations. My objectives were to 1) evaluate the potential impacts that reduced-altitude tactical speed military aircraft might generate on nesting colonial waterbirds, and to place any impacts in the context of other human events, 2) a) identify key least tern (Sternula antillarum) demographic drivers, b) evaluate the accuracy of assigning nest fates without using remote cameras, and c) assess the effects of camera-monitoring on nest survival, and 3) evaluate the agreement between two techniques used to estimate peak least tern breeding abundance. I conducted my study at Cape Lookout National Seashore, North Carolina from May-August 2010-2012. I surveyed colonies once every 3-5 days and deployed audio recorders and time-lapse cameras at individual nests in 9 colonies. Birds did not incubate less or engage in alert behaviors during overflights compared with control periods. Least terns reduced incubation by a mean of 12% when pedestrians were observed near nests (S = -2.2, p = 0.04). Demographic effects from overflights or recreation are unlikely given the patterns of use in this study. Least tern demographic rates were driven by raccoon depredation. Cameras reduced daily nest survival (SE) from 0.85 (0.06) to 0.79 (0.08). However, cameras also decreased the frequency of unknown or misclassified nest fates by > 30%. Incubating adult counts were effective in assessing peak nest abundance at colonies where topography did not impede scanning from the perimeter. / Master of Science

There is little information on demographic trends of, or threats to the Wilson's Plover (Charadrius wilsonia), despite concerns that habitat degradation may be causing the species to decline. I studied Wilson's Plover demography, nest site selection, and physiological and behavioral responses to overflights at Cape Lookout National Seashore, North Carolina, where the National Park Service and U.S. Marine Corps recently lowered the altitude for overflights at tactical speeds. I monitored the responses of incubating Wilson's Plovers to overflights and other human activities and compared heart rate, incubation rate, and vigilance behaviors during time periods with and without these stimuli. I compared habitat use vs. availability at the island-scale, and nest placement relative to geomorphic features and vegetative cover, both on a local and island-wide scale. Wilson's Plovers increased vigilance during military rotary-wing and civilian fixed-wing overflights, but not during military fixed-wing overflights. Plovers were vigilant more and incubated less when researchers were present. Wilson's Plovers selected for interdune areas, flats and isolated dunelets on flats, and against beach and dunes. At the local scale, nests were more likely to be near dense vegetation than random points. Mayfield nest survival was 25%, and predation caused most of the nest failure. Daily nest survival was negatively correlated with nest age and initiation date. Nests with cameras and heart rate monitors had lower survival, and nests with predator exclosures had higher survival. The mean number of chicks fledged per pair was 0.78. / Master of Science