Bald eagle recovery, most likely reasons:

1. Bald and Golden Eagle Protection Act of 1969 banned their slaughter, made prison a consequence of harming them.

2. DDT ban in USA reduced the egg shell thinning issues that made for more successful clutches.

3. Increased domestication over time encouraged more urbanized breeding opportunities that opened up further prey bases / habitats. (e.g. Chicago River Basin, Adjacent to freeways throughout the nation, etc.)

4. Lead ban of 1991 for waterfowl? I don't know about that one way or the other. I'd need data on the number of lead toxicity cases in relation to the population at large from pre-1991 reconciled against data from today. Brent may be correct that the ban reduced mortality but I don't have the data.