Northern Goshawks typically hunt birds and small mammals, including crows, squirrels, and rabbits, both within the forest and along the forest edge. They often perch in trees while watching for prey; this Goshawk appears to be using the fence for that purpose! The Audubon Guide to North American Birds (the source for the information provided above) has more photos and information regarding this fascinating predator.
If you have photos or information regarding birds of interest in the Laramie area, please feel free to share them with us!