In the Delaware Valley, signs of that recovery are everywhere.
In southern New Jersey around Salem County, several dozen eagles now make their nests.
Eagles also nest in Montgomery County and near Phoenixville, within six miles of the King of Prussia Mall.
Last winter, birders discovered a nest at the Philadelphia Navy Yard. It was the first nest within city limits in two centuries. The birds later abandoned it, but wildlife officials expect them to try again next year.
Many heralded the eagle's delisting as a sign that the Endangered Species Act works and as proof of what a healthier environment can revive.
"Simply put, it says if we provide birds with clean air, clean water, clean food, and a place to nest, they will do well," said Keith Bildstein, director of conservation science at Hawk Mountain, north of Reading.
The mountainous area has a natural gap that funnels migrating eagles and other raptors. Photos from long ago show hunters gunning them down as they winged by.
Starting in midcentury, eagle numbers declined further because the pesticide DDT accumulated in their tissues and caused the birds' eggshells to thin and break.
But now, so many eagles fly past Hawk Mountain that birders with binoculars line the ridgetops every fall.
In the 1970s, they might have seen only 18 bald eagles in a fall migration. The annual average over the last decade is 162 of the majestic birds.
Pennsylvania now has at least 120 nesting pairs, up from a low of only three in 1983. That year, the state Game Commission began capturing eaglets from wilderness nests in Canada and releasing them in the state.
New Jersey has 59 nesting pairs, up from a low of one throughout the 1970s.
Despite the national gains, eagles remain listed as "threatened" in Pennsylvania and "endangered" in New Jersey. Officials in both states said they might reconsider.
