The largest North American owl (though the Great Horned Owl is more massive) is a resident of the remote boreal forests of Canada and of some remote areas of the western U.S. On occasion in winter, numbers of Great Grays and other northern owls wander south in search of better hunting. While nocturnal and crepuscular (active at twilight), the Great Gray is often active by day. It is rather fearless and oblivious to human approach: the birds shown here continued to hunt, unconcerned with our presence. Their huge facial disks complement their incredible hearing, allowing them to hunt small mammals even hidden below inches of snow. Its call is a very deep and booming hoo, hoo, hoo. This was a memorable trip with my birding mentor Stan Arnold and included a chance encounter with Jim Brighton and Hans Holbrook, destined to become good friends.