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Image of hawk owl.

Home for Hawk Owls

Long considered winter migrants in Minnesota, northern hawk owls sometimes
nest here. Should they also be counted as summer residents of our north woods?

by Michael Furtman

I was lost but the owl wasn't. It knew exactly where it was and what it wanted to do.

I was on a quest to find and photograph my first northern hawk owl. And by good fortune, I'd just found one here—though after having taken so many turns along back roads in a bog northwest of Duluth, I wasn't sure where here was.

Video of Hawk Owls in Minnesota

This video, courtesy of Sparky Stensaas, shows a hawk owl hunting in Minnesota.

Perched atop a spindly spruce, the owl turned its yellow eyes on me, assessed me as no threat, and resumed its hunt, calmly staring at the snow below. The day was as clear and bright as it was cold—nearly 20 below zero—and my eyes ached from the sun reflecting off the snow. I wondered how this owl could hunt not only by day but also in such bright light.

As I watched, its entire body grew excited, intent. Its spotted head cocked side to side. Suddenly the bird hunched forward and dropped from the spruce with its long tail cocked jauntily and wings tucked. Halfway to the ground, this feathered bullet unfolded its wings and, seconds later, extended its heavily feathered legs, revealing fierce talons. With a swoop, it scooped up an unfortunate vole, returned to its perch, and downed the rodent in nearly a single gulp.

I lowered the camera through which I had viewed this impressive display, gasping in awe.

My first encounter with a hawk owl occurred five years ago during a winter of a remarkable owl invasion. I thought, as many did, that these owls only visited Minnesota during winters of scant food to the north. But since that time I've seen them in summer, as have others. Could they possibly be breeding here? I was not alone in pondering that question.

A Bird of Swift, Strong Flight.

In the 1916 report The Winter Bird-Life of Minnesota, Dr. Thomas S. Roberts of the University of Minnesota described this bird for a Minnesota audience:

A medium-sized diurnal owl that occurs sparingly throughout the woodlands of the state, though apparently more numerous in the northern forests. It is a bird of swift, strong flight, and for its size, of much prowess. … When sitting quietly in the woods it is a tame and indifferent bird. … The Hawk Owl is 15 inches long; ashy brown and white, barred below and on back, and spotted on top of head and hindneck; breast white with middle dark patch on throat; no ear tufts; tail long and rounded.

The northern forests Roberts wrote of were those in Minnesota. In fact, the northern hawk owl breeds in the circumpolar boreal forest zone from Alaska east through Canada, and from Scandinavia through Siberia. Minnesota is on the southern margins of the species range. Nesting in hollows in the tops of broken trees or in woodpecker holes, it prefers open coniferous or mixed coniferous-deciduous forests. It particularly likes burned-over or blow-down openings in the forest and naturally occurring openings such as muskeg.

Because it tends to haunt remote areas and is normally found in very low numbers, you could say that the northern hawk is uncommon in Minnesota. I have lived in this state all my 56 years, yet wasn't even aware of them until the winter of 2004–05, when hundreds of northern owls—great gray and hawk owls—descended upon Minnesota. Both species feed primarily on mice, voles, and other small rodents; and a rodent shortage in Canada that winter drove the owls south. During that winter, a record 475 hawk owls were counted in Minnesota. While hawk owls are regularly seen nearly every winter in much lower numbers, this huge influx made it possible for many to view this remarkable bird, including myself.

And remarkable it is. Few other owls are diurnal—that is, hunt by day. As I traveled through remote areas of the state, time of day or brightness of sun seemed to have little effect on the number of hawk owls I found. They are seemingly immune to our presence as long as we don't get too near or infringe upon their hunt.

Hawk owls are unlike other owls in other ways too. They lack soft edges on their flight feathers, the singular trait that makes other owls' flight so silent for unsuspecting prey. Instead, the hawk owl relies on swift, steep, hawklike swoops, rather than the long, silent glide of other owls. They can also hover like a northern harrier, an uncommon ability for an owl. One morning in the Sax-Zim Bog, I watched as a hawk owl plummeted from its aspen perch, only to pull up six or eight feet above the ground and hover with beating wings for a few seconds before dropping on a deer mouse.

A hawk owl's anatomy also differs from that of other owls because it relies on vision for finding prey. Whereas most owls have a shallow facial disk to funnel sound to the ears, the hawk owl's face projects forward to improve the lines of sight. Hawk owls also have excellent hearing. But unlike owls with asymmetrical ears to triangulate the sounds of prey, hawk owls have symmetrical ears. In my experience, a hawk owl often hears its prey first, then turns to face that direction, yellow eyes searching the site of the last sound. But it waits until the rodent shows itself (or perhaps it can see the furrow forming beneath the snow) before leaping from its perch.

 

Minnesota Breeder?

It's long been documented, since the late 1800s, that northern hawk owls are a nomadic species that follows prey abundance, sometimes moving from Canada into Minnesota. It's also been documented that following these irruptions, a few hawk owls sometimes stay and nest here for a few years. But now there's a mild debate about whether or not hawk owls are here all the time and should be considered a resident breeding species.

No one has studied Minnesota hawk owl nesting more than Dave Grosshuesch, currently a biologist for Superior National Forest. And he believes hawk owls nest in Minnesota regularly. Prior to 2001, only eight records existed for hawk owls nesting in Minnesota, five of which occurred following an invasion. Since that time, Grosshuesch has compiled more reports from others or observed nesting himself in years that don't follow irruptions, including nine in one year. All nests have been located in the far north, from Roseau east to the tip of the Arrowhead.

"Great gray owls breed every year in Minnesota," said Grosshuesch. "Given the nature of the hawk owl, which is not much different than the great gray, I think hawk owls are a regular breeder. They travel all winter, following prey, and these exploratory flights can lead to nesting. Nomadic species like hawk owls may not breed here every year. But since 2006, I know that they have nested every year except one, and it is likely that they nested that year but just weren't documented. Minnesota is an important part of their range."

Carrol Henderson, DNR Nongame Wildlife Program supervisor, has come to agree.

"We used to think of them as an incidental species," Henderson said. "They nest in such inaccessible areas, though, that they could have been here every year without us knowing about them. But now with better understanding of where to look and more people looking, we're getting sightings of breeding pairs most years. I would now say they are a regular breeding species in Minnesota."

Vast areas of inaccessible bog, swaths of forest blow-down, and large burned-over areas all provide the snags and openings hawk owls prefer. All are habitats seldom visited by people. Quiet, small, solitary, and attracted to remote places, hawk owls likely have been breeding in Minnesota for decades beyond the notice of humans.

Grosshuesch's data reflects the reports of many dedicated birders and paid researchers who have been scouring these remote sites with increased intensity since the owl invasion. For example, Minnesota Ornithological Union member Jim Lind found three nesting pairs in Lake County. The Minnesota County Biological Survey, a DNR project to catalog species and habitats across the state, has also documented hawk owl sightings and has now added this species to the 235 other birds it considers breeding birds in our state.

One such nesting hawk owl sighting occurred just this past summer, when MCBS bird specialist Karl Bardon found an adult with four fledglings in a burned-over area in the Boundary Waters. Another hawk owl pair nested in the Sax-Zim Bog on a wildlife management area, where open spaces created for sharp-tailed grouse habitat provide a perfect hunting ground.

"The Minnesota Breeding Bird Atlas has 10 hawk owl breeding records so far," said Mark Martell, director of bird conservation for Audubon Minnesota, which has also added this species to its list of Minnesota breeding birds. "This is pretty definitive evidence that the species is breeding in the state," said Martell.

The early evidence seems to indicate that hawk owls find enough habitat in Minnesota to do well.

"Typically they've been found nesting in disturbed areas," said Grosshuesch, "which runs the gamut of forest blow-down, salvage logging, forest fires, and even in logging clear-cuts— as long as there remain some suitable perch trees and large, dead trees to nest. They also have been found nesting in places with mixed bog and agriculture, where they nest in the bogs but hunt rodents in the farm fields."

Like the lynx, which was also recently confirmed as breeding in our state, the hawk owls in Minnesota represent a breeding population at the southern edge of its range. The rash of nesting confirmations doesn't necessarily mean that they are new to Minnesota, but it likely reflects increased effort to seek them out.

Now that they've been confirmed as nesting here, birders and researchers will continue to monitor them. And while Audubon's Martell said it's "a bit premature to speculate on management implications until we know more about their habitat use and other factors," we now know they need suitable breeding habitat.


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