Plummage definitely was too clean to be a year old. It's lack of coordination was another good sign of being a relatively new flier. It was also looked like a male and males fledge first usually.
Other Bald Eagles have been reported in the Oshawa-whitby area over the last 10 days. and an accompaning adult could easily been near by hunting geese, swans, dumpsters and anything dead.
Durham region is a heavily birded area. Between that and the MNR monitoring of southern Ontario eagle nests the probability of one nesting in the immediate area without detection is very low. i.e. nil.
The nearest nest in the Peterbourgh area is probably and hr or so flight for a eagle. Hell I can drive to it in an hour from Oshawa. Most southern/Central Ontario eaglet should be fledged by now and in the process of separation from their parents if not separated. 3 weeks ago in northern Georgian Bay we saw eaglets over 1km from their nest trees already.
I heard a rumour of a nest in Burlington but been to busy with gulls and terns this summer to bother looking into it. I will be banding caspian terns in Hamilton on friday so I may find out more then.