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December 06, 2016
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Twenty years of bald eagles breeding along the Upper Delaware River

This young fledgling, about 15 weeks old, has unwanted attention from a male red-winged blackbird, which is harassing or "mobbing" the young eagle in order to drive it out of its territory. Parent eagles will assist their young for several weeks after they fledge, as they learn how to fend for themselves.

The Upper Delaware Scenic and Recreational River (UDS&RR), with its 73 miles of river from Hancock to just below Sparrowbush, NY, offers prime habitat, with much undisturbed area, many potential nesting locations and a plentiful uncontaminated source of food for the fish-eating bald eagle. It took close to a decade from the time the first hacked eagles reached breeding age until the first pair of bald eagles established a territory within the Upper Delaware River Area.

Eagles typically establish a nest and take a mate within 50 to 100 miles of their natal nest (where they themselves were raised). The spread of eagles was slow at first, and perhaps some of the area’s earlier territorial eagles may have originated from the Pennsylvania Game Commission’s hacking facility at nearby Shohola Lake in Pike County, PA. The first occupying pair appeared in 1993 along the river, but they did not produce young for the first two years, typical with some newly mated pairs.

The number of bald eagle pairs increased slowly but steadily over the next 20 years to the point that 19 breeding pairs were tallied during the past season in 2013. Nest surveys show that in some cases, the distance between the natal nest and that young's new territory was five miles or less.

Eagles reach breeding age at four to five years, and newly established territories by banded eagles has shown that they tend to get started young; five- to seven-year-old eagles was the norm for banded eagles and a four-year-old female was observed establishing a new territory with an older male (unbanded, but showing four-year sub-adult plumage).

It is impossible to determine the age of eagles by sight once they molt to full adult plumage at five years or so, so banded resightings by birders or photographers are very valuable.

The UDS&RR has proven its worth for bald eagle habitat; even before eagles started to breed here, winter visitors from Canada were utilizing the river for a winter food source while their own breeding habitat was frozen over. For our resident eagles now, the immediate threat is habitat loss. We as a people can work as partners and stewards to minimize this threat.

As I watch an eagle in flight, I stand in awe of nature's perfect airframe. Watching an eagle soar in a thermal, we can see a circle of motion. We are fortunate to live in an area where we are able to observe this winged one's circle of life.