Could it be that cam was set up to catch the collapse of the bridge?
For those of you not living in the area, the Sellwood Bridge (in the cam site) recently rated a 2 out of 100 for bridge safety (national scoring). Replacement design/funding has been held hostage by local politico's wanting light rail/trolley crossingsto connect the trolleys on both sides of the river, bicycle and pedestrian accommodations (a combination wider than the proposed traffic lanes total) etc. Buses and truck are not allowed on the bridge at all for the past few years. Thus my tongue in cheek comment.
And yes this is a great area for springers.