These cormorants are waiting for whatever cormorants wait for. Food? More than food? These rocks were under many more feet of water for decades in a huge mill pond.
Downstream of the cormorants, some of the later mill buildings survive, most repurposed as river-front apartments now that the dams are gone and the water is white, as it was through the early 1800s. This is the Chattahoochee at the Fall Line in Columbus.
Now, venturesome people in funky short kayaks dare the once-again fast-flowing river to overpower them. [This guy was just fine; this moment looks scary, however.]