Fig. 1. A diagram of the different levels of the obstacle course used to establish the maneuvering capabilities of cormorants. The numbers on the right are the horizontal distances between adjacent barriers (thick vertical lines). The vertical barrier in the center of all levels is B_0.5 (see text), which was kept at a fixed position inside the channel. The two neighboring barriers that were moved closer between trials are B₀ and B₁, respectively. The red line represents the trajectory of the birds through the course.