When this bird flew by silently and fairly low to the ground over the lake, near the edge of the lake, I thought it looked like a mid-sized raptor or owl. Smaller than an eagle, but larger than a Cooper's hawk. Never saw its head/beak, but it appeared stubby and the body/wings seemed wide compared to the length of the bird. Sorry the photos are so poor....
Using White Hot thermal palette
Male. My private collection from undergrad