Fig. 4. Mean ± s.d. swimming speeds of the great cormorant (N=8) inside the obstacle course. Data are plotted as a function of the mean turning radius in each difficulty level (see Fig. 3). Squares denote the present study on vertical maneuvers. The triangle denotes data from Ribak et al. (Ribak et al., 2005) for the same birds during unobstructed swimming in a straight line (turning radius=).