Mergansers are among the few duck species that engage in cooperative hunting to herd and corral fish. This pack-hunting behavior allows large flocks to overwhelm schools of fish much more effectively than an individual bird could alone. Three dozen mergansers appeared in the water in front of the cabin. Working together, they would charge into shore to capture fish by pinning them to the shore. Once a charge was complete, those birds who had captured a fish would then have to defend their prize from their fellows.