Northern Goshawk is the largest and scarcest of the North American accipiters, making it sought after by birders. They nest in coniferous forest across northern North America. Although they are typically not seen south of Pennsylvania during summer, they nest throughout the mountainous areas of the western states and into Mexico. Even though widespread they are never dense. Goshawk is notoriously aggressive toward intruders near their nest, and defend them relentlessly and loudly! Biologists conducting nest research are wary and wear protective gear or face bloody consequences.
Unlike the other accipiters, Goshawk eats mammals (including squirrels and hares) equally as much as birds (i.e. flickers, jays, Grouse, Ptarmigan). They are seldom encountered except at a few hawk migration sites. Goshawk moves south into the Lower 48 and US-Canada border region in numbers roughly every ten years in response to prey population cycles. They can be seen in semi-open areas in winter but are still secretive. They are vocal, emitting a loud, screaming "Kak-Kak-Kak...", slower, louder, and deeper than Cooper's Hawk. Females approach the size and bulk of Red-tailed Hawk, but males not much larger than female Cooper's Hawk.
(Map from Cornell Lab of Ornithology's All About Birds. For dynamic distribution maps, visit the eBird website.)