There is a pretty good population of Bald Eagles in Montmorency County in Michigan. Back in the 1960's there were only two nesting sites as far as I am aware of. The locals tried to be as secretive as possible about their location to keep them safe and unmolested. Now there are plenty of them and they fly over the lakes looking for fish and eat road kill and have a quite visible presence. No doubt the Philly conservationists hope for the same outcome and will try to keep the nesting sites secret.