At the Jo Hays lookout along Route 26, looking to the Northeast over Happy Valley, you can see hawks and other raptors that are using this ridgeline as a "highway" to the south. Migrations are particularly good to see on days with winds from the Northwest.
In Central PA hawk migration really gets under way in mid-September. The first species that tends to move through is the smallest of the Buteo family of hawks, the Broad-Winged Hawk. This species likes to travel in groups called "kettles". One kettle of Broad-Wingeds can have hundreds of birds in it, all moving south together. Like other birds that flock, migrating in groups can provide safety, especially to smaller species that may fall prey to larger raptors.
Other species that follow include Sharp-shinned hawks, Cooper's Hawks, Red-shouldered Hawks, and Red-tailed Hawks.
Hawkwatch sites are also a great vantage point to spot migrating Bald Eagles and Golden Eagles. These larger birds typically move through in the highest numbers near the end of the migration season in November.
If you're going to go looking for hawks and eagles, it's important to bring a spotting scope or a pair of binoculars to get the best looks. However, if you don't own any of these, but are going to a popular hawkwatch site during peak migration, you will likely find a friendly birder who will let you look through their scope.
You can search for hawkwatch sites around the country at the Hawk Migration Association of North America's website: http://hmana.org/
If you go, be sure to report what you see to your local birding club or http://ebird.org/content/ebird/
It's an important exercise in Citizen Science. Comparing hawkwatch data from year to year can give us a critical look at the health of our raptor populations.
One of the most famous and historic hawk watch sites in Pennsylvania is the Hawk Mountain Sanctuary in Kempton, PA. Shaver's Creek will be bringing to of our Eagles to Hawk Mountain's Golden Eagle Saturday on November 12th. You can visit their website for more information: http://www.hawkmountain.org/
If you aren't able to make it up to Jo Hays Vista this fall, try going back in the spring when birders will be here almost every day in April and May counting Golden Eagles as they return north.