From Rhody Peach
The Northern Hawk Owl is a striking bird that looks like a mash-up of an owl and a hawk. Unlike most owls, it has a long tail and a slim, streamlined body that gives it a very hawk-like silhouette in flight. Its bold black-and -white facial markings and piercing yellow eyes make it instantly recognizable, even from a distance.
One of the most unusual things about the Northern Hawk Owl is that it is active during the day. While many owls hunt at night, this species prefers daylight, especially in the long summer days of the far north. Its excellent eyesight allows it to spot prey from treetops or utility poles, where it sits perfectly still before swooping down with incredible speed and accuracy.
Northern Hawk Owls are powerful hunters despite their moderate size. They mainly feed on small mammals such as voles and mice, but they will also catch birds when the opportunity arises. In years when rodent populations boom, these owls may raise more young and even expand their range farther south than usual, surprising birdwatchers in places where they are rarely seen.
These owls are native to the boreal forests of North America, Europe, and Asia, thriving in cold climates with open woodland and clearings. Instead of nesting in tree cavities like many owls, Northern Hawk Owls often use broken treetops or abandoned nests left behind by other large birds. This preference for exposed nesting sites gives them excellent visibility but also makes them more vulnerable to predators.
Another fascinating trait is their fearless personality. Northern Hawk Owls are known to aggressively defend their territory and young, sometimes diving at animals-and even humans-that come too close. This bold behavior, combined with their sharp hunting skills and daytime activity, makes the Northern Hawk Owl one of the most distinctive and captivating owls in the world.

Was gonna say “Boreal owl” but then saw Northern Hawk Owl and thought, oh well guess they just look alike, but - are they the same owl?
A very commendable guess! They share a lot of features, but they are not the same owl. Let us examine!
Left is the NHO, right is the Boreal.
Both have similar colors and patterns and are found throughout the boreal (sub-arctic forest) regions of North America and Eurasia.
NHO is the only member of genus Surnia (called monotypic because there's just one type!) and is most closely related to the pygmy owls. NHO is about 15 inches / 40 cm long and 300ish grams, while the largest pygmy owl is, I think, the Ferruginous Pygmy Owl, at 7 inches / 18 cm and 70 grams.
Boreal is of genus Aegolius, making it cousins to the Saw Whet type owls. They're about 10 inches / 25 cm and 140 grams.
NHO is primarily a daylight hunter, while Boreal is more nocturnal, but because of long hours of sunlight in the summers, it can hunt when it's light.
NHO is sleeker in appearance, with a smaller head and long tail, while BO is stout and round with a short tail. BO has white "eyebrows", while NHO has none, NHO has horizontal bands on the tummy, while BO has vertical streaks.
Boreals are cavity nesters, living in holes in trees, while the larger Hawk Owl will nest in snags (tress where the top has fallen off and a depression eroded in the top.
Birds at a snag: