February 2, 2023
New snow fell two days ago, and it still covers the dense Russian-olive limbs on this sunny morning. We’re standing just inside a dense thicket in western Montana’s Mission Valley. Originally planted for pheasant habitat, this thicket is dominated by non-native plants. Russian-olives (Elaeagnus angustifolia) form a thick canopy overhead. Dense clumps of Siberian peashrub (Caragana arborescens) make up a shrubby understory. The dormant stalks of common burdock (Arctium minus) and poison-hemlock (Conium maculatum) emerge from the snow around us.
“They make it their profession to blend in,” says Beth Mendelsohn.
She’s talking about long-eared owls – and specifically, the male long-eared owl who is peering down from the Russian-olive behind us. His posture is upright, his earlike feather tufts partially raised. Beth is a research biologist with the Owl Research Institute (ORI), a nonprofit based in Charlo, Montana. This morning we’re out with her and Denver Holt, ORI’s founder. And as you might suspect, given the name of this nonprofit, we’re researching owls.
Long-eared owl habitat
Two volunteers, John Zardis and Jeremiah Thompson, have joined us here today in this Russian-olive thicket. This spot provides promising habitat for long-eared owls, in summer as well as winter. The dense shrubs give roosting cover and nest sites, while the snow-covered fields nearby offer hunting opportunities. Like many of our winter raptors, long-eared owls feed heavily on voles – and in the Mission Valley, the voles are abundant this year.
“There’s a ton of voles,” Beth tells me.
Like many small mammals, vole populations fluctuate from year to year. This winter’s high vole numbers seem to bode well for our day in the field – and so does this male long-eared owl, watching us from his camouflaged perch in the Russian-olive.
Just a few yards from him, a platform nest of sticks rests high among the branches of the thicket. Long-eared owls don’t build their own nests – this one was originally built by black-billed magpies. But for the last two years, a pair of long-eared owls has nested here.
It’s rather unusual for these birds to reuse a nest, let alone reuse it twice. But once again, there’s an owl here, perching close to the nest as another spring approaches. Is it just a coincidence?
“Maybe he’s setting up territory,” says Denver.
Roosting, nesting, wandering
Long-eared owls roost communally in the winter, using thickets like this one. Denver tells us that he often finds them perching three to six feet off the ground, where overhanging branches provide extra cover. Where the habitat is good, with plenty of shelter and plenty of voles, these winter roosts can be impressively large. One year, the Owl Research Institute documented an astounding 88 long-eared owls in a single western Montana roost.
Eventually, sometime around March, the roosting congregations will break up and the owls will begin to set up breeding territories. First, a male will appear near a nest. A bit later in the season, both the male and female will be visible nearby. Then she’ll begin incubating, crouched low and well-hidden on her platform of sticks, while the male continues to perch close to hand.
Denver Holt founded the Owl Research Institute in 1988. Since then, the organization has banded over 2000 long-eared owls in the valleys of western Montana. The leg bands allow for the identification of individual birds. And through the decades, work by ORI has painted a detailed picture of our local long-eared owl populations.
Long-eared owls are wanderers. Although some individuals from the winter roosts will stay to nest nearby, others basically vanish. There’s little continuity from one year to the next in the specific individuals that make up a winter roost. To draw a human analogy, the roosts are like college dorms rather than local coffee groups: every year, it’s a different community. And it’s a similar story during the breeding season. Although some of these birds do nest in the same area from one year the next, the majority don’t come back.
From Montana to Guanajuato
How far do long-eared owls wander? One bird banded by ORI in June turned up in Guanajuato, Mexico the next May. Unfortunately, it was dead. Another bird showed up in Arizona. But to find a banded owl so far away is rare. Of the 2000-plus long-eared owls that ORI has banded, they’ve re-encountered about 500 of them locally. The rest have just disappeared.
This field day is one small part of this decades-long research project. We want to find out how many owls are using these thickets now. Can we find a winter roost? We’ll search the habitat thoroughly and count the owls here. If we find a large roost, we’ll set up mist nests and try to catch the owls and band them.
The research we’re doing involves a certain amount of disturbance to the owls – and as such, it’s highly regulated. ORI has all of the necessary permits to handle the owls on their study sites. They carefully safeguard the locations of the winter roosts to protect the birds from harassment.
The male long-eared owl tolerates our presence for perhaps 30 seconds, then takes off, flying over our heads. He disappears silently into the thicket ahead of us.
Are there more owls in this thicket? It’s time to find out. We position ourselves in a spaced-out line, far enough apart that each of us can just barely see the person next to them through the thick branches. Denver is at one end of the line, just outside of the thicket. Having one person out in the open will give us a better chance of spotting any owls we may flush.
Crawling through the thicket
Ready, go! We start walking slowly through the Siberian peashrub, trying to keep our line even. We’re ducking under branches and crawling through narrow openings. From time to time, a branch tries to snatch my hat or dumps its load of snow down my neck. As we move forward, we’re checking the tangles thoroughly for perching owls and watching for birds that may flush ahead of us. We’re also peering at the ground, looking for clues. Roosting long-eared owls regurgitate thumb-sized pellets of fur and bones, which accumulate under their roosts. And when they defecate, they leave behind chalky deposits of whitewash.
The recent snowfall makes it less likely that we’ll find whitewash or pellets. And although we’re checking these thickets rather thoroughly, the owl roost we were hoping to find isn’t materializing. A few times, a silent, winged shadow appears from the bushes in front of us and flies farther ahead. But this is very likely just the same male who was watching us from the Russian-olive earlier. We think it’s possible we could be flushing a second bird, as well, but we’re never able to confirm that more than one owl is present.
Although the thicket is so extensive that it takes us several hours to complete our search, we don’t manage to find a communal owl roost. Nevertheless, the scramble through the bushes is far from boring. This thicket may not be supporting many long-eared owls this winter, but a variety of other creatures are calling it home.
Porcupines, pheasants, and bobcats
The branches of one Siberian peashrub bush gleam white, the bark stripped off by the incisors of a hungry porcupine. Occasionally a ring-necked pheasant flies away from us with a sudden whir of wings. Small groups of black-capped chickadees, American tree sparrows, and black-billed magpies chirp and squawk as we struggle through the dense branches.
Sets of ring-necked pheasant tracks crisscross the interior of the thicket. The trail of a coyote or a fox angles through the bushes. And even more exciting, a set of bobcat tracks meanders past, weaving among the dense Siberian peashrub and elderberry.
In the sparse snow at the base of a bush, I find the wing feathers of a ring-necked pheasant. It’s another scene where a predator has caught dinner. Nearby are some smaller down feathers that have partially frozen into the ice. The pheasant kill isn’t very recent – clearly, it’s older than the bobcat tracks. But as that sharp-nosed feline passed, it too noticed the feathers. The tracks show us that the bobcat walked right up to the dead pheasant. Finding nothing left to eat, it didn’t linger. I imagine the bobcat sniffing the feathers momentarily, then continuing onwards.
Where are the owls?
But where are the owls this winter? According to Beth and Denver, a large roost has occupied this thicket in past years. I wonder if the snow might be too deep right now, making it difficult to hunt the voles underneath.
It’s important to remember, though, that looking for a long-eared owl roost in these thickets is like searching for the proverbial needle in a haystack. Although we’ve covered a lot of ground today, this general area of the Mission Valley is dotted with many more thickets of Russian-olive, Siberian peashrub, and willow. And any of them might hold a long-eared owl roost.
“Studying owls is super fun because it’s really hard. Not many people do it, and there’s a lot to learn,” Beth tells me.
She indicates some of the other thickets in this area, which we haven’t had time to check today. “There’s probably like 40 of them roosting over there.”
This isn’t the case everywhere, though. In parts of the Missoula Valley, sprawling development has replaced the thickets and grassland where long-eared owls used to reside. And although with a nomadic species like the long-eared owl, it can be difficult to separate habitat loss from other factors, the decades of study by ORI do make it clear that our local long-eared owl populations are declining.
Life in the thicket
Where we are today, though, in the Mission Valley, the habitat still looks good for long-eared owls. We haven’t found a major winter roost yet this year – but we’re pretty sure there’s one out here, somewhere. And in the meanwhile, this thicket of Russian-olive and Siberian peashrub is supporting ring-necked pheasants, American tree sparrows, a roaming bobcat, and a porcupine. And out of sight, camouflaged among the branches, we know there’s a male long-eared owl. If we’re lucky, maybe he’ll stay and nest here.
Important note: Owl research involves a certain amount of necessary disturbance to the birds. ORI holds all of the necessary permits to do these important studies, which allow us to better understand and conserve these cryptic, fascinating animals. If you are interested in finding out about volunteer opportunities, contact ORI. And if you’re just out birding for fun and you happen to encounter a long-eared owl, please, please be respectful. Follow the American Birding Assocation’s code of birding ethics. Keep your distance, minimize disturbance, and please don’t publicize sensitive information such as the locations of winter roosts. Thank you.
Celis-Murillo, A., Malorodova, M., & Nakash, E. (2022). North American Bird Banding Program Dataset 1960-2022 retrieved 2022-07-14. U.S. Geological Survey data release. Retrieved from https://www.sciencebase.gov/catalog/item/632b2d7bd34e71c6d67bc161
Marks, J.S., Evans, D.L., & Holt, D.W. (2020). Long-eared Owl (Asio otus). In Birds of the World (S.M. Billerman, ed.). Ithaca, NY: Cornell Lab of Ornithology. Retrieved from https://birdsoftheworld.org/bow/species/loeowl
Marks, J.S., Hendricks, P. & Casey, D. (2016). Birds of Montana. Arrington, VA: Buteo Books.
Owl Research Institute. (n.d.) Research focus: long-eared owls. Retrieved from https://www.owlresearchinstitute.org/long-eared-owl-research