There is nothing more majestic to see in the Upstate New York sky than a bald eagle soaring or circling overhead. Their mere presence in a tree top can stop traffic, cause people to pull out their cameras, or just gawk at the massive and unique-looking bird. I can remember when it was extremely rare to spot an eagle in this area. Now, thanks to a combination of conservation efforts, bald eagles are much more common around here. In fact, more than once a week, I spot at least two bald eagles in the vicinity of my home (on Swiss Hill Road and Hessinger and Lare Road). Each time, seeing them makes me stop whatever I am doing to just watch them fly by.
This time of year, from December to February, bald eagles migrate their northern nests to 
this area mostly because of the large sections of undisturbed wooded land and the abundance of ponds, lakes and rivers that do not completely freeze over. Open water found near power plants, where they discharge water during energy production, is another populate place to locate wintering eagles. Railroad tracks and highways provide an ample supply of dead animals (carrion) for scavenging eagles as well.
I guess you could say that bald eagles, like many city residents, have discovered the Catskills and Hudson River area a great place for a second home!
Bald eagle viewing during the winter months, from a safe distance and at planned observation sites, can offer an exhilarating and memorable experience. Intensive monitoring and well-documented sightings have helped determine New York’s most popular eagle wintering habitats.
According to the Department of Environmental Conservation (DEC), in 1997 a nesting pair
produced the first eagle born along the Hudson River in more than 100 years! In 2005, 12 pairs nested and 18 eaglets were fledged along the river. In recent winters, more than 100 wintering eagles have been counted along the lower Hudson.
The Hudson River, the Upper Delaware River watershed, and sections of the St. Lawrence River provide winter eagle viewing opportunities. Winter eagle-watching has become a popular off-season activity in the Upper Delaware Valley, where DEC works cooperatively with the Delaware Highlands Conservancy and the National Park Service to help visitors find and properly observe wintering eagles.
DEC maintains two well-marked viewing areas in the Mongaup Valley on the Rio and Mongaup Falls reservoirs (off NY Route 42). There is an information/observation booth at Mongaup Falls. There are several pull off areas along Route 97, which winds along the shore of the Delaware River, to spot eagles hunting for a meal.
The above picture is of Bill Streeter demonstrating the massive wing span of a juvenile bald eagle that was rescued in the Basha Kill area, in the Town of Mamakating.
Here is a link to a fact sheet from the DEC on Bald Eagles in the Hudson River area: http://www.dec.ny.gov/animals/74052.html
Reference:
Department of Environmental Conservation. Bald Eagles of the Hudson. Web Jan, 5, 2017. http://www.dec.ny.gov/animals/9382.html