As noted, here, here, here and here, Tanner Springs Park has turned into quite the hot spot for urban wildlife—and a little survival of the fittest. First came the fish, then the osprey and now the ducks. The fish have dwindled in number, the osprey are looking well-fed and we've lost a duckling—wildlife 101 is playing out in the city!
The Portland Tribune has a great article on the history of the fish, their introduction to Tanner Springs, and Nature's remedy for a situation that our Parks Department couldn't control.
That looks like one of the falcons that live in on the bridges. I was fortunate to come upon one hanging out on the fountain in front of my building downtown - The Standard Center. What a sight. So beautiful.
Save the fishies
It is not a falcon it is a Osprey