Responses of wintering bald eagles to boating activity

Wintering populations of bald eagles show a close association with open water (Spencer 1976, Steenhof 1978). With the dramatic increase in the use of waterways for recreational activity in recent decades (Brockman and Merriam 1973, Jensen 1973), concern has arisen regarding the effects of boating activity on wintering eagles (Stalmaster 1980). Boating activity can be detrimental because it disrupts feeding activity and affects large areas in short periods of time (Skagen 1980, Stalmaster 1980). Disturbance may result in increased energy expenditures due to avoidance flights and decreased energy intake due to interference with feeding activity (Stalmaster 1980). In this paper we examine flushing responses and flight distances of wintering bald eagles to a canoe of two adjacent rivers with widely disparate levels of boating activity. We examine individual and interactive effects of eagle age, behavior, and social grouping.