Dabbling duck behavior and aircraft activity in coastal North Carolina

Requests to increase military aircraft activity in some training facilities in the United States have prompted the need to determine if waterfowl and other wildlife are adversely affected by aircraft disturbance. We quantified behavioral responses of wintering American black ducks (Anas rubripes), American wigeon (A. americana), gadwall (A, streptera), and American green-winged teal (A. crecca carolinensis) exposed to low-level flying military aircrafts; at Piney and Cedar islands, North Carolina, in 1991 and 1992. Waterfowl spent less than or equal to 1.4% of their time responding to aircraft, which included flying, swimming, and alert behaviors. Mean duration of responses by species ranged from 10 to 40 sec. Costs to each species were deemed low because disruptions represented a low percentage of their time-activity budgets, only a small proportion of birds reacted to disturbance (13/672; 2%), and the likelihood of resuming the activity disrupted by an aircraft disturbance event was high (64%). Recorded levels of aircraft disturbance (i.e., (x) over bar = 85.1 dBA) were not adversely affecting the time-activity budgets of selected waterfowl species wintering at Piney and Cedar islands.