We spotted this bird along the Keanakolu Road on the west slope of Mauna Kea, Hawaii yesterday. It was eating some small bird, possibly a chick of a Ring-necked Pheasant or a Erckel's Francolin. We watched from the bus window as it finished its meal then repositioned itself to digest while perched on this rock.
The most recent DNA evidence shows that the Hawaiian Hawk's closest relative is the Short-tailed Hawk. You can read more about it and all other Hawaiian birds in the online monograph,